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Accumulating evidence suggests that in utero exposures can influence the development of the immune system. Few studies have investigated whether prenatal exposure to persistent organic pollutants (POPs) is associated with allergy-related phenotypes in childhood, nor explored sex differences. We examined the association between prenatal exposure to POPs and offspring allergic outcomes in early and mid-childhood. We included 682 mother–child pairs from the prospective birth cohort Rhea. We measured dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB) and 6 polychlorinated biphenyl (PCB) congeners in maternal first trimester serum. Parents completed the questionnaires adapted from the International Study on Asthma and Allergy in Childhood (ISAAC) for allergy-related phenotypes when their children were 4 and 6 years old. We used Poisson regression models to estimate Risk Ratios. Prenatal HCB was associated with increased risk for rhinoconjunctivitis at 6 years (RR (95% CI): 2.5; (1.3, 4.8) for a doubling in the exposure). Among girls, prenatal DDE was associated with increased risk for current wheeze, current asthma and current rhinoconjunctivitis at 4 years (RR (95%CI): 1.4 (0.8, 2.6), 1.6 (1.1, 2.4) and 1.8 (1.0, 3.3) and p-interaction = 0.035, 0.027 and 0.059, respectively), with increased risk for current rhinoconjunctivitis at 6 years (RR (95%CI): 1.7 (0.7, 3.8) and p-interaction = 0.028) and total PCBs were associated with increased risk for current eczema at 4 years (RR (95%CI): 2.1 (1.1, 4.2) and p-interaction = 0.028). In boys, prenatal DDE was associated with decreased risk for current wheeze and current asthma at 4 years. Our findings suggest that even low levels of exposure to POPs prenatally may affect the development of childhood allergy-related outcomes in a sex and age-specific manner.

Urinary metabolic profiling is a promising powerful tool to reflect dietary intake and can help understand metabolic alterations in response to diet quality. Here, we used 1H-NMR spectroscopy in a multi-country study in European children (1147 children from 6 different cohorts) and identified a common panel of 4 urinary metabolites (hippurate, N-methylnicotinic acid, urea and sucrose) that was predictive of Mediterranean diet adherence (KIDMED) and ultra-processed food (UPF) consumption and also had higher capacity in discriminating children’s diet quality than that of established sociodemographic determinants. Further, we showed that the identified metabolite panel also reflected the associations of these diet quality indicators with C-peptide, a stable and accurate marker of insulin resistance and future risk of metabolic disease. This methodology enables objective assessment of dietary patterns in European child populations, complementary to traditional questionary methods, and can be used in future studies to evaluate diet quality. Moreover, this knowledge can provide mechanistic evidence of common biological pathways that characterize healthy and unhealthy dietary patterns, and diet-related molecular alterations that could associate to metabolic disease.

Epidemiological studies mostly focus on single environmental exposures. This study aims to systematically assess associations between a wide range of prenatal and childhood environmental exposures and cognition. The study sample included data of 1298 mother-child pairs, children were 6–11 years-old, from six European birth cohorts. We measured 87 exposures during pregnancy and 122 cross-sectionally during childhood, including air pollution, built environment, meteorology, natural spaces, traffic, noise, chemicals and life styles. The measured cognitive domains were fluid intelligence (Raven's Coloured Progressive Matrices test, CPM), attention (Attention Network Test, ANT) and working memory (N-Back task). We used two statistical approaches to assess associations between exposure and child cognition: the exposome-wide association study (ExWAS) considering each exposure independently, and the deletion-substitution-addition algorithm (DSA) considering all exposures simultaneously to build a final multiexposure model. Based on this multiexposure model that included the exposure variables selected by ExWAS and DSA models, child organic food intake was associated with higher fluid intelligence (CPM) scores (beta = 1.18; 95% CI = 0.50, 1.87) and higher working memory (N-Back) scores (0.23; 0.05, 0.41), and child fast food intake (−1.25; −2.10, −0.40), house crowding (−0.39; −0.62, −0.16), and child environmental tobacco smoke (ETS) (−0.89; −1.42, −0.35), were all associated with lower CPM scores. Indoor PM2.5 exposure was associated with lower N-Back scores (−0.09; −0.16, −0.02). Additional associations in the unexpected direction were found: Higher prenatal mercury levels, maternal alcohol consumption and child higher perfluorooctane sulfonic acid (PFOS) levels were associated with better cognitive performance; and higher green exposure during pregnancy with lower cognitive performance. This first comprehensive and systematic study of many prenatal and childhood environmental risk factors suggests that unfavourable child nutrition, family crowdedness and child indoor air pollution and ETS exposures adversely and cross-sectionally associate with cognitive function. Unexpected associations were also observed and maybe due to confounding and reverse causality., Graphical abstract Prenatal and childhood exposome-wide associations with child fluid intelligence (CPM). The exposures selected by Deletion-substitution-addition algorithm are represented by a triangle. Child fluid intelligence is mainly associated with childhood exposome, fast-food (negative association, left sided) and organic food consumption (positive, right sided), house crowding (negative, left sided), and child environmental tobacco smoke (ETS, negative, left sided). Image 1, Highlights • Previous evidence for environmental risk factor associations with neurodevelopment is based on analyses of single exposures. • We systematically analysed multiple environmental exposures in relation to child neurodevelopment. • The findings describe a list of outcome-related exposures: Diet, house crowding, indoor air pollution and tobacco smoke. • The findings show methodological complexities of analysing multiple exposures and their associations with neurodevelopment.

Background: Exposure to per- and polyfluoroalkyl substances (PFAS), a prevalent class of persistent pollutants, may increase the risk of type 2 diabetes. Objective: We examined associations between PFAS exposure and glucose metabolism in youth. Methods: Overweight/obese adolescents from the Study of Latino Adolescents at Risk of Type 2 Diabetes (SOLAR; n=310) participated in annual visits for an average of 3.3±2.9y. Generalizability of findings were tested in young adults from the Southern California Children’s Health Study (CHS; n=135) who participated in a clinical visit with a similar protocol. At each visit, oral glucose tolerance tests were performed to estimate glucose metabolism and β-cell function via the insulinogenic index. Four PFAS were measured at baseline using liquid chromatography–high-resolution mass spectrometry; high levels were defined as concentrations >66th percentile. Results: In females from the SOLAR, high perfluorohexane sulfonate (PFHxS) levels (≥2.0 ng/mL) were associated with the development of dysregulated glucose metabolism beginning in late puberty. The magnitude of these associations increased postpuberty and persisted through 18 years of age. For example, postpuberty, females with high PFHxS levels had 25-mg/dL higher 60-min glucose (95% CI: 12, 39mg/dL; p

The human exposome affects child development and health later in life, but its personal external levels, variability, and correlations are largely unknown. We characterized the personal external exposome of pregnant women and children in eight European cities. Panel studies included 167 pregnant women and 183 children (aged 6-11 years). A personal exposure monitoring kit composed of smartphone, accelerometer, ultraviolet (UV) dosimeter, and two air pollution monitors were used to monitor physical activity (PA), fine particulate matter (PM2.5), black carbon, traffic-related noise, UV-B radiation, and natural outdoor environments (NOE). 77% of women performed the adult recommendation of >= 150 min/week of moderate to vigorous PA (MVPA), while only 3% of children achieved the childhood recommendation of >= 60 min/day MVPA. 11% of women and 17% of children were exposed to daily PM2.5 levels higher than recommended >= 25 mu g/m(3)). Mean exposure to noise ranged from Lden 51.1 dB in Kaunas to Lden 65.2 dB in Barcelona. 4% of women and 23% of children exceeded the recommended maximum of 2 Standard-Erythemal-Dose of UV-B at least once a week. 33% of women and 43% of children never reached the minimum NOE contact recommendation of >= 30 min/week. The variations in air and noise pollution exposure were dominated by between-city variability, while most of the variation observed for NOE contact and PA was between-participants. The correlations between all personal exposures ranged from very low to low (Rho

There is growing evidence associating inflammatory markers in complex, higher order neurological functions, such as cognition and memory. We examined whether high levels of various inflammatory markers are associated with cognitive outcomes at 4 years of age in a mother-child cohort in Crete, Greece (Rhea study). We included 642 children in this cross-sectional study. Levels of several inflammatory markers (IFN-γ, IL-1β, IL-6, IL-8, IL-17α, IL-10, MIP-1α, TNF-α and the ratios of IL-6 to IL-10 and TNF-α to IL-10) were determined in child serum via immunoassay. Neurodevelopment at 4 years was assessed by means of the McCarthy Scales of Children’s Abilities. Multivariate linear regression analyses were used to estimate the associations between the exposures and outcomes of interest after adjustment for various confounders. Our results indicate that children with high TNF-α concentrations (≥90th percentile) in serum demonstrated decreased scores in memory (adjusted β = −4.0; 95% CI: −7.7, −0.2), working memory (adjusted β = −4.0; 95% CI: −8.0, −0.1) as well as in memory span scale (adjusted β = −4.0; 95% CI: −7.9, −0.1). We also found that children with high IFN-γ serum levels showed lower scores in memory span scale (adjusted β = −3.4; 95% CI: −7.3, −0.4). Children with elevated TNF-α/IL-10 ratio demonstrated decreased quantitative (adjusted β = −4.3; 95% CI: −8.2, −0.4), motor (adjusted β = −3.5; 95% CI: −7.5, −0.5), executive function (adjusted β = −4.8; 95% CI: −8.5, −1.1), general cognitive (adjusted β = −3.6; 95% CI: −7.3, −0.1), memory (adjusted β = −3.8; 95% CI: −7.6, −0), working memory (adjusted β = −3.5; 95% CI: −7.5, −0.5) and memory span scores (adjusted β = −5.3; 95% CI: −9.1, −1.4) The findings suggest that high levels of TNF-α may contribute to reduced memory performance at preschool age.

Background/objectives Polyunsaturated fatty acid (PUFA) status during pregnancy has been suggested to influence offspring obesity and cardiometabolic health. We assessed whether prenatal PUFA exposure is associated with rapid infant growth, childhood BMI, and cardiometabolic profile.Subjects/methods In the Dutch MEFAB (n = 266) and Greek RHEA (n = 263) cohorts, we measured n-3 and n-6 PUFA concentrations in cord blood phospholipids, which reflect fetal exposure in late pregnancy. We defined rapid infant growth from birth to 6 months of age as an increase in weight z-score >0.67. We analyzed body mass index (BMI) as continuous and in categories of overweight/obesity at 4 and 6 years. We computed a cardiometabolic risk score at 6-7 years as the sum of waist circumference, non-high-density lipoprotein cholesterol and blood pressure z-scores. Associations of PUFAs with child health outcomes were assessed using generalized linear models for binary outcomes and linear regression models for continuous ones after adjusting for important covariates, and for the pooled estimates, a cohort indicator.Results In pooled analyses, we found no association of PUFA levels with rapid infant growth, childhood BMI (beta per SD increase in the total n-3:n-6 PUFA ratio = -0.04 SD; 99% CI: -0.15, 0.06; P = 0.65 at 4 years, and -0.05 SD; 99% CI: -0.18, 0.08; P = 0.78 at 6 years), and overweight/obesity. We also found no associations for clustered cardiometabolic risk and its individual components. The results were similar across cohorts.Conclusions Our findings suggest that PUFA concentrations at birth are not associated with later obesity development and cardiometabolic risk in childhood.

BACKGROUND AND AIM: Perfluoroalkyl substances (PFAS), the “forever chemicals”, accumulate mainly in the liver and have various adverse health effects. Little is known about the mechanistic pathways...

Background Early-life antibiotic use has been hypothesized to promote weight gain and increase the risk of childhood obesity. Objectives To examine the associations of prenatal and infant antibiotics with childhood growth, adiposity and cardiometabolic traits in the Greek Rhea cohort. Methods We used data from 747 mother-child pairs with anthropometric measurements drawn from medical records or measured at 4 and 6 years of age. Antibiotic exposure was assessed by maternal report during pregnancy and at the first year of life. Children were classified as exposed to antibiotics prenatally if the mother received at least one course of oral antibiotics during pregnancy and postnatally if the mother reported that the child received at least one oral antibiotic treatment during the first year of life. Outcomes included repeated weight, body mass index (BMI), waist circumference, body fat (%), total cholesterol and blood pressure. We applied mixed effects, linear and log-binomial regression models after adjusting for important covariates. Results Around 14.6% of the participating children were prenatally exposed to antibiotics and 32.4% received antibiotics during the first year of life. Prenatal exposure to antibiotics was associated with a twofold increase in the risk for obesity (risk ratio [RR]; 95% confidence interval [CI]: 2.09 [1.58, 2.76]) and abdominal obesity (RR [95% CI]: 2.56 [1.89, 3.47]) at 6 years. Postnatal exposure to antibiotics was associated with increased weight (beta [95% CI]: 00.25 [0.06, 0.44]) and BMI (beta [95% CI]: 0.23 [0.003, 0.45]) SD scores from 2 to 7 years of life. Conclusion Early-life antibiotic use was associated with accelerated childhood growth and higher adiposity.

Maintaining thyroid homeostasis during pregnancy is vital for fetal development. The few studies that have investigated associations between metal exposure and gestational thyroid function have yielded mixed findings. To evaluate the association of exposure to a mixture of toxic metals with thyroid parameters in 824 pregnant women from the Rhea birth cohort in Crete, Greece. Concentrations of three toxic metals [cadmium (Cd), antimony (Sb), lead (Pb)] and iodine were measured in urine using inductively coupled plasma mass spectrometry and thyroid hormones [Thyroid Stimulating Hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3)] were measured in serum in early pregnancy. Associations of individual metals with thyroid parameters were assessed using adjusted regression models, while associations of the metal mixture with thyroid parameters were assessed using Bayesian Kernel Machine Regression (BKMR).Women with high (3rd tertile) concentrations of urinary Cd, Sb and Pb, respectively, had 13.3 % (95%CI: 2.0 %, 23.2 %), 12.5 % (95%CI: 1.8 %, 22.0 %) and 16.0 % (95%CI: 5.7 %, 25.2 %) lower TSH compared to women with low concentrations (2nd and 1st tertile). In addition, women with high urinary Cd had 2.2 % (95%CI: 0.0 %, 4.4 %) higher fT4 and 4.0 % (95%CI: −0.1 %, 8.1 %) higher fT3 levels, and women with high urinary Pb had 4 % (95%CI: 0.2 %, 8.0 %) higher fT3 levels compared to women with low exposure. The negative association of Cd with TSH persisted only when iodine sufficiency was unfavorable. BKMR attested that simultaneous exposure to toxic metals was associated with decreased TSH and increased fT3 and revealed a potential synergistic interaction of Cd and Pb in association with TSH. The present results suggest that exposure to toxic metals even at low levels can alter gestational thyroid homeostasis.

Background: Child blood pressure (BP) is predictive of future cardiovascular risk. Prenatal exposure to metals has been associated with higher BP in childhood, but most studies have evaluated elements individually and measured BP at a single time point. We investigated impacts of prenatal metal mixture exposures on longitudinal changes in BP during childhood and elevated BP at 11 years of age. Methods: The current study included 176 mother-child pairs from the Rhea Study in Heraklion, Greece and focused on eight elements (antimony, arsenic, cadmium, cobalt, lead, magnesium, molybdenum, selenium) measured in maternal urine samples collected during pregnancy (median gestational age at collection: 12 weeks). BP was measured at approximately 4, 6, and 11 years of age. Covariate-adjusted Bayesian Varying Coefficient Kernel Machine Regression and Bayesian Kernel Machine Regression (BKMR) were used to evaluate metal mixture impacts on baseline and longitudinal changes in BP (from ages 4 to 11) and the development of elevated BP at age 11, respectively. BKMR results were compared using static versus percentile-based cutoffs to define elevated BP. Results: Molybdenum and lead were the mixture components most consistently associated with BP. J-shaped relationships were observed between molybdenum and both systolic and diastolic BP at age 4. Similar associations were identified for both molybdenum and lead in relation to elevated BP at age 11. For molybdenum concentrations above the inflection points (~ 40-80 μg/L), positive associations with BP at age 4 were stronger at high levels of lead. Lead was positively associated with BP measures at age 4, but only at high levels of molybdenum. Potential interactions between molybdenum and lead were also identified for BP at age 11, but were sensitive to the cutoffs used to define elevated BP. Conclusions: Prenatal exposure to high levels of molybdenum and lead, particularly in combination, may contribute to higher BP at age 4. These early effects appear to persist throughout childhood, contributing to elevated BP in adolescence. Future studies are needed to identify the major sources of molybdenum and lead in this population. This work was supported by NIEHS [grant numbers R21ES029681 (Chatzi, Conti, McConnell), R01ES030691 (Chatzi, Conti, McConnell, Eckel), R01ES029944 (Chatzi, Conti, Margetaki), R01 ES030364 (Chatzi, Conti, McConnell, Eckel), R21ES028903 (Chatzi, McConnell, Eckel), P30ES007048 (Chatzi, Conti, McConnell, Eckel), K99 ES030400 (Howe), R00ES024144 (Farzan), and Horizon 2020 – European Framework Programme for Research and Innovation, ATHLETE, (Chatzi, Conti), P01CA196569, R01CA140561, R01ES016813 (Conti)]. The Rhea project was financially supported by the European Union [grant numbers EU FP6–2003-Food-3-NewGeneris, EU FP6. STREP Hiwate, EU FP7 ENV.2007.1.2.2.2. Project No 211250 Escape, EU FP7–2008-ENV-1.2.1.4 Envirogenomarkers, EU FP7-HEALTH-2009- single stage CHICOS, EU FP7 ENV.2008.1.2.1.6. Proposal No 226285 ENRIECO, EU- FP7- HEALTH-2012 Proposal No 308333 HELIX) and the Greek Ministry of Health.

BackgroundMaternal thyroid hormones’ supply is crucial for fetal neurodevelopment; however, the role of maternal mild thyroid dysfunction is not clear. We aimed to assess the association of maternal mild thyroid dysfunction with child neuropsychological development from infancy to early childhood.MethodsWe included 757 mother–child pairs from the prospective ‘Rhea’ cohort on Crete, Greece. Maternal thyroid functioning was assessed by quantitative analysis of serum thyroid-stimulating hormone, free thyroxine, thyroid peroxidase antibodies and thyroglobulin antibodies at early gestation (mean=14 weeks). Neuropsychological assessment was based on Bayley Scales of Infant Development (18 months of age), McCarthy Scales of Children’s Abilities (4 years of age), Raven’s Coloured Progressive Matrices, Trail Making Test and Finger Tapping Test (6 years of age).ResultsIn multivariate adjusted linear regression analyses, maternal hypothyroxinemia was associated with decreased verbal scores at 4 years and reduced motor speed at 6 years of age. Maternal thyroid autoimmunity was associated with decreased child perceptual and motor ability at 4 years of age. Four trajectories of longitudinal non-verbal cognitive development were identified and children exposed to maternal thyroid autoimmunity had increased risk for belonging to an adverse trajectory (‘low’: adjusted relative risk ratio (RRR) = 2.7 95% CI: (1.4, 5.2), ‘high-decreasing’: adjusted RRR = 2.2 95% CI: (1.2, 4.0), ‘low-increasing’: adjusted RRR = 1.8 95% CI: (1.0, 3.2)).ConclusionMaternal hypothyroxinemia is associated with reduced offspring verbal and motor ability. Maternal thyroid autoimmunity is associated with decreased offspring perceptual performance and motor ability and increased risk for adverse non-verbal cognitive development from infancy to childhood.

The early-life exposome influences future health and accelerated biological aging has been proposed as one of the underlying biological mechanisms. We investigated the association between more than 100 exposures assessed during pregnancy and in childhood (including indoor and outdoor air pollutants, built environment, green environments, tobacco smoking, lifestyle exposures, and biomarkers of chemical pollutants), and epigenetic age acceleration in 1,173 children aged 7 years old from the Human Early-Life Exposome project. Age acceleration was calculated based on Horvath’s Skin and Blood clock using child blood DNA methylation measured by Infinium HumanMethylation450 BeadChips. We performed an exposure-wide association study between prenatal and childhood exposome and age acceleration. Maternal tobacco smoking during pregnancy was nominally associated with increased age acceleration. For childhood exposures, indoor particulate matter absorbance (PMabs) and parental smoking were nominally associated with an increase in age acceleration. Exposure to the organic pesticide dimethyl dithiophosphate and the persistent pollutant polychlorinated biphenyl-138 (inversely associated with child body mass index) were protective for age acceleration. None of the associations remained significant after multiple-testing correction. Pregnancy and childhood exposure to tobacco smoke and childhood exposure to indoor PMabs may accelerate epigenetic aging from an early age The study received funding from the European Community’s Seventh Framework Programme (FP7/2007-206) (grant agreement no 308333) (HELIX project), the H2020-EU.3.1.2. - Preventing Disease Programme (grant agreement no 874583) (ATHLETE project), and from the European Union’s Horizon 2020 research and innovation programme (grant Agreement number: 733206) (Early Life stressors and Lifecycle Health (LIFECYCLE)). BiB received funding from the Welcome Trust (WT101597MA), from the UK Medical Research Council (MRC) and Economic and Social Science Research Council (ESRC) (MR/N024397/1). INMA was supported by grants from the Instituto de Salud Carlos III, CIBERESP, and the Generalitat de Catalunya-CIRIT. KANC was funded by the grant of the Lithuanian Agency for Science Innovation and Technology (6-04-2014_31V-66). The Norwegian Mother, Father and Child Cohort Study is supported by the Norwegian Ministry of Health and Care Services and the Ministry of Education and Research. The Rhea project was financially supported by European projects (EU FP6-2003-Food-3-NewGeneris, EU FP6. STREP Hiwate, EU FP7 ENV.2007.1.2.2.2. Project No 211250 Escape, EU FP7-2008-ENV-1.2.1.4 Envirogenomarkers, EU FP7-HEALTH-2009- single stage CHICOS, EU FP7 ENV.2008.1.2.1.6. Proposal No 226285 ENRIECO, EU- FP7- HEALTH-2012 Proposal No 308333 HELIX), and the Greek Ministry of Health (Program of Prevention of obesity and neurodevelopmental disorders in preschool children, in Heraklion district, Crete, Greece: 2011-2014; “Rhea Plus”: Primary Prevention Program of Environmental Risk Factors for Reproductive Health, and Child Health: 2012-15). We acknowledge support from the Spanish Ministry of Science and Innovation through the “Centro de Excelencia Severo Ochoa 2019-2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program. OR was funded by a UKRI Future Leaders Fellowship (MR/S03532X/1). MV-U and CR-A were supported by a FI fellowship from the Catalan Government (FI-DGR 2015 and #016FI_B 00272). MC received funding from Instituto Carlos III (Ministry of Economy and Competitiveness) (CD12/00563 and MS16/00128) SI

DAL’s contribution to this paper is supported by the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007–2013/ERC grant agreement no 669545) and a UK National Institute of Health Senior Investigator (NF-0616-10102). TC’s contribution is supported by European Union’s Horizon 2020 research and innovation programme under grant agreement No 733206 (LifeCycle). MLV has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 707404. The opinions expressed in this document refect only the author’s view. The European Commission is not responsible for any use that may be made of the information it contains. The INfancia y Medio Ambiente (INMA)-Sabadell cohort was funded by grants from Instituto de Salud Carlos III (Red INMA G03/176; CB06/02/0041; CP18/00018; PI041436; PI081151; PI1100610 incl. FEDER funds). ISGlobal acknowledge support from the Spanish Ministry of Science and Innovation through the “Centro de Excelencia Severo Ochoa 2019–2023” Program (CEX2018-000806-S). SA is funded by a Juan de la Cierva—Incorporación Postdoctoral Contract awarded by Ministry of Economy, Industry and Competitiveness (IJCI-2017-34068). JJ holds Miguel Servet-II contract (CPII19/00015) awarded by the Instituto de Salud Carlos III (Co-funded by European Social Fund “Investing in your future”). MC holds a Miquel ServetI cotract (CP16/00128) awarded by the Instituto de Salud Carlos III (co-funded by European Social Fund "Investing in your future"). The INMA-Asturias cohort is funded by grants from Instituto de Salud Carlos III (FISS PI 04/2018, FISS PI09/02311, FISS PI13/02429, FISS PI18/00909 including FEDER funds) and University of Oviedo. This study was funded by Instituto de Salud Carlos III through the projects ‘CP14/00108 & PI16/00261’ (co-funded by European Regional Development Fund ‘A way to make Europe’) (…), Alemany, S., Avella-García, C., Liew, Z., García-Esteban, R., Inoue, K., Cadman, T., López-Vicente, M., González, L., Riaño Galán, I., Andiarena, A., Casas, M., Margetaki, K., Strandberg-Larsen, K., Lawlor, D.A., El Marroun, H., Tiemeier, H., Iñiguez, C., Tardón, A., Santa-Marina, L., Júlvez, J., Porta, D., Chatzi, L., Sunyer, J.

BACKGROUND/AIM: Inflammation provides a substrate for mechanisms that underlie the association of maternal diet during pregnancy with Attention Deficit-Hyperactivity Disorder (ADHD) symptoms in childhood. However, no previous study has quantified the proinflammatory potential of maternal diet as a risk factor for ADHD. Thus, we evaluated the association of maternal dietary inflammatory index (DII(®)) scores during pregnancy with ADHD symptoms in 4 year-old children born in two Mediterranean regions. METHODS: We analyzed data from two population-based birth cohort studies – INMA (Environment and Childhood) four subcohorts in Spain (N=2,097), and RHEA study in Crete (Greece) (N=444). The DII score of maternal diet was calculated based on validated food frequency questionnaires completed during pregnancy (12(th) and/or 32(nd) week of gestation). ADHD symptoms were assessed by ADHD-DSM-IV in INMA cohort and by ADHDT test in RHEA cohort, with questionnaires filled-out by teachers and parents, respectively. The associations between maternal DII and ADHD symptoms were analysed using multivariable-adjusted zero-inflated negative binomial regression models in each cohort study separately. Meta-analysis was conducted to combine data across the cohorts for fitting within one model. RESULTS: The DII was significantly higher in RHEA (RHEA=2.09 [1.94, 2.24]) in comparison to INMA subcohorts (Asturias=−1.52 [−1.67,−1.38]; Gipuzkoa=−1.48 [−1.64,−1.33]; Sabadell=−0.95 [−1.07,−0.83]; Valencia= −0.76 [−0.90,−0.62]). Statistically significant reduced risk of inattention symptomatology (OR = 0.86; CI 95% = 0.77–0.96), hyperactivity symptomatology (OR = 0.82; CI 95% = 0.72–0.92) and total ADHD symptomatology (OR = 0.82; CI 95%= −0.72–0.93) were observed with increased maternal DII in boys. No statistically significant associations were observed in girls between maternal DII and inattention, hyperactivity and total ADHD symptomatology. CONCLUSIONS: We found reduced risk of ADHD symptomatology with increased DII only in boys. This relationship requires further exploration in other settings.

Background: Multiple omics technologies are increasingly applied to detect early, subtle molecular responses to environmental stressors for future disease risk prevention. However, there is an urgent need for further evaluation of stability and variability of omics profiles in healthy individuals, especially during childhood. Methods: We aimed to estimate intra-, inter-individual and cohort variability of multi-omics profiles (blood DNA methylation, gene expression, miRNA, proteins and serum and urine metabolites) measured 6 months apart in 156 healthy children from five European countries. We further performed a multi-omics network analysis to establish clusters of co-varying omics features and assessed the contribution of key variables (including biological traits and sample collection parameters) to omics variability. Results: All omics displayed a large range of intra- and inter-individual variability depending on each omics feature, although all presented a highest median intra-individual variability. DNA methylation was the most stable profile (median 37.6% inter-individual variability) while gene expression was the least stable (6.6%). Among the least stable features, we identified 1% cross-omics co-variation between CpGs and metabolites (e.g. glucose and CpGs related to obesity and type 2 diabetes). Explanatory variables, including age and body mass index (BMI), explained up to 9% of serum metabolite variability. Conclusions: Methylation and targeted serum metabolomics are the most reliable omics to implement in single time-point measurements in large cross-sectional studies. In the case of metabolomics, sample collection and individual traits (e.g. BMI) are important parameters to control for improved comparability, at the study design or analysis stage. This study will be valuable for the design and interpretation of epidemiological studies that aim to link omics signatures to disease, environmental exposures, or both The study has received funding from the European Community’s Seventh Framework Programme (FP7/2007-206) under grant agreement no 308333 (HELIX project) and the H2020-EU.3.1.2. - Preventing Disease Programme under grant agreement no 874583 (ATHLETE project). Additionally, BiB received core infrastructure funding from the Wellcome Trust (WT101597MA) and a joint grant from the UK Medical Research Council (MRC) and Economic and Social Science Research Council (ESRC) (MR/N024397/1). INMA data collections were supported by grants from the Instituto de Salud Carlos III, CIBERESP, and the Generalitat de Catalunya-CIRIT. KANC was funded by the grant of the Lithuanian Agency for Science Innovation and Technology (6-04-2014_31V-66). The Rhea project was financially supported by European projects (EU FP6-2003-Food-3-NewGeneris, EU FP6. STREP Hiwate, EU FP7 ENV.2007.1.2.2.2. Project No 211250 Escape, EU FP7-2008-ENV- 1.2.1.4 Envirogenomarkers, EU FP7-HEALTH-2009- single stage CHICOS, EU FP7 ENV.2008.1.2.1.6. Proposal No 226285 ENRIECO, EU- FP7- HEALTH-2012 Proposal No 308333 HELIX), and the Greek Ministry of Health (Program of Prevention of obesity and neurodevelopmental disorders in preschool children, in Heraklion district, Crete, Greece: 2011- 2014; “Rhea Plus”: Primary Prevention Program of Environmental Risk Factors for Reproductive Health, and Child Health: 2012-15). The CRG/UPF Proteomics Unit is part of the Spanish Infrastructure for Omics Technologies (ICTS OmicsTech) and it is a member of the ProteoRed PRB3 consortium which is supported by grant PT17/0019 of the PE I+D+i 2013-2016 from the Instituto de Salud Carlos III (ISCIII) and ERDF. We acknowledge support from the Spanish Ministry of Science and Innovation and State Research Agency through the “Centro de Excelencia Severo Ochoa 2019-2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program. MV-U and CR-A were supported by a FI fellowship from the Catalan Government (FI-DGR 2015 and #016FI_B 00272). MC received funding from Instituto Carlos III (Ministry of Economy and Competitiveness) (MS16/00128). LM is funded by a Juan de la Cierva-Incorporación fellowship (IJC2018-035394-I) awarded by the Spanish Ministerio de Economía, Industria y Competitividad SI

Background: The urban environment is characterised by many exposures that may influence hypertension development from early life onwards, but there is no systematic evaluation of their impact on child blood pressure (BP). Methods: Systolic and diastolic blood pressure were measured in 4,279 children aged 4-5 years from a multi-centre European cohort (France, Greece, Spain, and UK). Urban environment exposures were estimated during pregnancy and childhood, including air pollution, built environment, natural spaces, traffic, noise, meteorology, and socioeconomic deprivation index. Single- and multiple-exposure linear regression models and a cluster analysis were carried out. Results: In multiple exposure models, higher child BP, in particular diastolic BP, was observed in association with higher exposure to air pollution, noise and ambient temperature during pregnancy, and with higher exposure to air pollution and higher building density during childhood (e.g., mean change [95% confidence interval] for an interquartile range increase in prenatal NO2 = 0.7 mmHg[0.3;1.2]). Lower BP was observed in association with higher temperature and better street connectivity during childhood (e.g., temperature = -1.1[-1.6;-0.6]). Some of these associations were not robust in the sensitivity analyses. Mother-child pairs were grouped into six urban environment exposure clusters. Compared to the cluster representing the least harmful urban environment, the two clusters representing the most harmful environment (high in air pollution, traffic, noise, and low in green space) were both associated with higher diastolic BP (1.3[0.1;2.6] and 1.5[0.5;2.5]). Conclusion: This first large systematic study suggests that living in a harmful urban environment may impact BP regulation in children. These findings reinforce the importance of designing cities that promote healthy environments to reduce long-term risk of hypertension and other cardiovascular diseases. This work was supported by funding from the European Community’s Seventh Framework Programme [FP7/2007–206 n°308333; the HELIX project], and by the European Union’s Horizon 2020 research and innovation programme [H2020 n°733206; the LifeCycle project]. CW holds a Sara Borrell fellowship from the Instituto de Salud Carlos III [CD18/00132]. INMA data collections were supported by grants from the Instituto de Salud Carlos III, CIBERESP, and the Generalitat de Catalunya- CIRIT (Spain). The Rhea project was financially supported by European projects, and the Greek Ministry of Health (Program of Prevention of obesity and neurodevelopmental disorders in preschool children, in Heraklion district, Crete, Greece: 2011–2014; “Rhea Plus”: Primary Prevention Program of Environmental Risk Factors for Reproductive Health, and Child Health: 2012–15). The work was also supported by MICINN [MTM2015-68140-R] and Centro Nacional de Genotipado- CEGEN- PRB2- ISCIII (Spain). This paper presents independent research funded by the National Institute for Health Research (NIHR) under its Collaboration for Applied Health Research and Care (CLAHRC) for Yorkshire and Humber (UK). Core support for Born in Bradford is also provided by the Wellcome Trust (WT101597MA, UK). The EDEN study was supported by Foundation for medical research (FRM), National Agency for Research (ANR), National Institute for Research in Public health (IRESP: TGIR cohorte santé 2008 program), French Ministry of Health (DGS), French Ministry of Research, INSERM Bone and Joint Diseases National Research (PRO-A), and Human Nutrition National Research Programs, Paris-Sud University, Nestlé, French National Institute for Population Health Surveillance (InVS), French National Institute for Health Education (INPES), the European Union FP7 programmes (ESCAPE, ENRIECO, Medall projects), Diabetes National Research Program (through a collaboration with the French Association of Diabetic Patients (AFD)), French Agency for Environmental Health Safety (now ANSES), Mutuelle Générale de l’Education Nationale a complementary health insurance (MGEN), French national agency for food security, French-speaking association for the study of diabetes and metabolism (ALFEDIAM).

Background DNA methylation has been shown to be associated with adiposity in adulthood. However, whether similar DNA methylation patterns are associated with childhood and adolescent body mass index (BMI) is largely unknown. More insight into this relationship at younger ages may have implications for future prevention of obesity and its related traits. Methods We examined whether DNA methylation in cord blood and whole blood in childhood and adolescence was associated with BMI in the age range from 2 to 18 years using both cross-sectional and longitudinal models. We performed meta-analyses of epigenome-wide association studies including up to 4133 children from 23 studies. We examined the overlap of findings reported in previous studies in children and adults with those in our analyses and calculated enrichment. Results DNA methylation at three CpGs (cg05937453, cg25212453, and cg10040131), each in a different age range, was associated with BMI at Bonferroni significance, P −7, with a 0.96 standard deviation score (SDS) (standard error (SE) 0.17), 0.32 SDS (SE 0.06), and 0.32 BMI SDS (SE 0.06) higher BMI per 10% increase in methylation, respectively. DNA methylation at nine additional CpGs in the cross-sectional childhood model was associated with BMI at false discovery rate significance. The strength of the associations of DNA methylation at the 187 CpGs previously identified to be associated with adult BMI, increased with advancing age across childhood and adolescence in our analyses. In addition, correlation coefficients between effect estimates for those CpGs in adults and in children and adolescents also increased. Among the top findings for each age range, we observed increasing enrichment for the CpGs that were previously identified in adults (birth Penrichment = 1; childhood Penrichment = 2.00 × 10−4; adolescence Penrichment = 2.10 × 10−7). Conclusions There were only minimal associations of DNA methylation with childhood and adolescent BMI. With the advancing age of the participants across childhood and adolescence, we observed increasing overlap with altered DNA methylation loci reported in association with adult BMI. These findings may be compatible with the hypothesis that DNA methylation differences are mostly a consequence rather than a cause of obesity.

Introduction: Early onset and high prevalence of allergic diseases result in high individual and socio-economic burdens. Several studies provide evidence for possible effects of environmental factors on allergic diseases, but these are mainly single-exposure studies. The exposome provides a novel holistic approach by simultaneously studying a large set of exposures. The aim of the study was to evaluate the association between a broad range of prenatal and childhood environmental exposures and allergy-related outcomes in children. Material and methods: Analyses of associations between 90 prenatal and 107 childhood exposures and allergy-related outcomes (last 12 months: rhinitis and itchy rash; ever: doctor-diagnosed eczema and food allergy) in 6-11 years old children (n = 1270) from the European Human Early-Life Exposome cohort were performed. Initially, we used an exposome-wide association study (ExWAS) considering the exposures independently, followed by a deletion-substitution-addition selection (DSA) algorithm considering all exposures simultaneously. All the exposure variables selected in the DSA were included in a final multi-exposure model using binomial general linear model (GLM). Results: In ExWAS, no exposures were associated with the outcomes after correction for multiple comparison. In multi-exposure models for prenatal exposures, lower distance of residence to nearest road and higher di-iso-nonyl phthalate level were associated with increased risk of rhinitis, and particulate matter absorbance (PMabs) was associated with a decreased risk. Furthermore, traffic density on nearest road was associated with increased risk of itchy rash and diethyl phthalate with a reduced risk. DSA selected no associations of childhood exposures, or between prenatal exposures and eczema or food allergy. Discussion: This first comprehensive and systematic analysis of many environmental exposures suggests that prenatal exposure to traffic-related variables, PMabs and phthalates are associated with rhinitis and itchy rash. This work was supported by the European Community’s Seventh Framework Programme [grant agreement no 308333—the HELIX project]; Instituto de Salud Carlos III; CIBERESP; Conselleria de Sanitat; Generalitat Valenciana; Department of Health of the Basque Government; Provincial Government of Gipuzkoa; Generalitat de Catalunya-CIRIT; Lithuanian Agency for Science Innovation and Technology [grant number 6-04-2014_31V-66]; Norwegian Ministry of Health and Care Services; Norwegian Ministry of Education and Research; Greek Ministry of Health; Ministerio de Ciencia Innovacion y Universidades [grant number MTM2015-68140-R]; Centro Nacional de Genotipado-CEGEN-PRB2-ISCIII; Fondation de France.

Current knowledge on environmental causation for psychiatric disorders suggests a complex picture with a multitude of social, physical and chemical exposures occurring at different stages of life. ...

Background Fetal smoke exposure is a common and key avoidable risk factor for birth complications and seems to influence later risk of overweight. It is unclear whether this increased risk is also present if mothers smoke during the first trimester only or reduce the number of cigarettes during pregnancy, or when only fathers smoke. We aimed to assess the associations of parental smoking during pregnancy, specifically of quitting or reducing smoking and maternal and paternal smoking combined, with preterm birth, small size for gestational age, and childhood overweight. Methods and findings We performed an individual participant data meta-analysis among 229,158 families from 28 pregnancy/birth cohorts from Europe and North America. All 28 cohorts had information on maternal smoking, and 16 also had information on paternal smoking. In total, 22 cohorts were population-based, with birth years ranging from 1991 to 2015. The mothers’ median age was 30.0 years, and most mothers were medium or highly educated. We used multilevel binary logistic regression models adjusted for maternal and paternal sociodemographic and lifestyle-related characteristics. Compared with nonsmoking mothers, maternal first trimester smoking only was not associated with adverse birth outcomes but was associated with a higher risk of childhood overweight (odds ratio [OR] 1.17 [95% CI 1.02–1.35], P value = 0.030). Children from mothers who continued smoking during pregnancy had higher risks of preterm birth (OR 1.08 [95% CI 1.02–1.15], P value = 0.012), small size for gestational age (OR 2.15 [95% CI 2.07–2.23], P value < 0.001), and childhood overweight (OR 1.42 [95% CI 1.35–1.48], P value < 0.001). Mothers who reduced the number of cigarettes between the first and third trimester, without quitting, still had a higher risk of small size for gestational age. However, the corresponding risk estimates were smaller than for women who continued the same amount of cigarettes throughout pregnancy (OR 1.89 [95% CI 1.52–2.34] instead of OR 2.20 [95% CI 2.02–2.42] when reducing from 5–9 to ≤4 cigarettes/day; OR 2.79 [95% CI 2.39–3.25] and OR 1.93 [95% CI 1.46–2.57] instead of OR 2.95 [95% CI 2.75–3.15] when reducing from ≥10 to 5–9 and ≤4 cigarettes/day, respectively [P values < 0.001]). Reducing the number of cigarettes during pregnancy did not affect the risks of preterm birth and childhood overweight. Among nonsmoking mothers, paternal smoking was associated with childhood overweight (OR 1.21 [95% CI 1.16–1.27], P value < 0.001) but not with adverse birth outcomes. Limitations of this study include the self-report of parental smoking information and the possibility of residual confounding. As this study only included participants from Europe and North America, results need to be carefully interpreted regarding other populations. Conclusions We observed that as compared to nonsmoking during pregnancy, quitting smoking in the first trimester is associated with the same risk of preterm birth and small size for gestational age, but with a higher risk of childhood overweight. Reducing the number of cigarettes, without quitting, has limited beneficial effects. Paternal smoking seems to be associated, independently of maternal smoking, with the risk of childhood overweight. Population strategies should focus on parental smoking prevention before or at the start, rather than during, pregnancy., Elise Philips and co-workers investigate parental smoking and associated birth and child outcomes., Author summary Why was this study done? Maternal smoking during pregnancy is an important risk factor for various birth complications and childhood overweight. It is not clear whether this increased risk is also present if mothers smoke during the first trimester only or reduce the number of cigarettes during pregnancy. The associations of paternal smoking with birth and childhood outcomes also remain unknown. What did the researchers do and find? We conducted an individual participant data meta-analysis using data from 229,158 families from 28 pregnancy and birth cohorts from Europe and North America to assess the associations of parental smoking during pregnancy, specifically of quitting or reducing smoking and maternal and paternal smoking combined, with preterm birth, small size for gestational age, and childhood overweight. We observed that smoking in the first trimester only did not increase the risk of preterm birth and small size for gestational age but was associated with a higher risk of childhood overweight, as compared to nonsmoking. Reducing the number of cigarettes during pregnancy, without quitting, was still associated with higher risks of these adverse outcomes. Paternal smoking seems to be associated, independently of maternal smoking, with the risks of childhood overweight. What do these findings mean? Population strategies should focus on parental smoking prevention before or at the start of, rather than during, pregnancy. Future studies are needed to assess the specific associations of smoking in the preconception and childhood periods with offspring outcomes.

Background: The adverse health effects of early life exposure to tobacco smoking have been widely reported. In spite of this, the underlying molecular mechanisms of in utero and postnatal exposure to tobacco smoke are only partially understood. Here, we aimed to identify multi-layer molecular signatures associated with exposure to tobacco smoke in these two exposure windows. Methods: We investigated the associations of maternal smoking during pregnancy and childhood secondhand smoke (SHS) exposure with molecular features measured in 1203 European children (mean age 8.1 years) from the Human Early Life Exposome (HELIX) project. Molecular features, covering 4 layers, included blood DNA methylation and gene and miRNA transcription, plasma proteins, and sera and urinary metabolites. Results: Maternal smoking during pregnancy was associated with DNA methylation changes at 18 loci in child blood. DNA methylation at 5 of these loci was related to expression of the nearby genes. However, the expression of these genes themselves was only weakly associated with maternal smoking. Conversely, childhood SHS was not associated with blood DNA methylation or transcription patterns, but with reduced levels of several serum metabolites and with increased plasma PAI1 (plasminogen activator inhibitor-1), a protein that inhibits fibrinolysis. Some of the in utero and childhood smoking-related molecular marks showed dose-response trends, with stronger effects with higher dose or longer duration of the exposure. Conclusion: In this first study covering multi-layer molecular features, pregnancy and childhood exposure to tobacco smoke were associated with distinct molecular phenotypes in children. The persistent and dose-dependent changes in the methylome make CpGs good candidates to develop biomarkers of past exposure. Moreover, compared to methylation, the weak association of maternal smoking in pregnancy with gene expression suggests different reversal rates and a methylation-based memory to past exposures. Finally, certain metabolites and protein markers evidenced potential early biological effects of postnatal SHS, such as fibrinolysis. The study has received funding from the European Community’s Seventh Framework Programme (FP7/2007-206) under grant agreement no. 308333 (the HELIX project); and the H2020-EU.3.1.2. - Preventing Disease Programme under grant agreement no 874583 (the ATHLETE project). BiB received core infrastructure funding from the Wellcome Trust (WT101597MA) and a joint grant from the UK Medical Research Council (MRC) and Economic and Social Science Research Council (ESRC) (MR/N024397/1). INMA data collections were supported by grants from the Instituto de Salud Carlos III, CIBERESP, and the Generalitat de Catalunya-CIRIT. KANC was funded by the grant of the Lithuanian Agency for Science Innovation and Technology (6-04-2014_31V-66). The Norwegian Mother, Father and Child Cohort Study is supported by the Norwegian Ministry of Health and Care Services and the Ministry of Education and Research. The RHEA project was financially supported by European projects and the Greek Ministry of Health (Program of Prevention of Obesity and Neurodevelopmental Disorders in Preschool Children, in Heraklion district, Crete, Greece: 2011–2014; “Rhea Plus”: Primary Prevention Program of Environmental Risk Factors for Reproductive Health, and Child Health: 2012–2015). The work was also supported by MICINN (MTM2015-68140-R) and Centro Nacional de Genotipado-CEGEN-PRB2-ISCIII. The CRG/UPF Proteomics Unit is part of the Spanish Infrastructure for Omics Technologies (ICTS OmicsTech), and it is a member of the ProteoRed PRB3 consortium which is supported by grant PT17/0019 of the PE I+D+i 2013-2016 from the Instituto de Salud Carlos III (ISCIII) and ERDF. We acknowledge support from the Spanish Ministry of Science and Innovation through the “Centro de Excelencia Severo Ochoa 2019-2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program.

Background: Chemical and nonchemical environmental exposures are increasingly suspected to influence the development of obesity, especially during early life, but studies mostly consider single exposure groups. Objectives: Our study aimed to systematically assess the association between a wide array of early-life environmental exposures and childhood obesity, using an exposome-wide approach. Methods: The HELIX (Human Early Life Exposome) study measured child body mass index (BMI), waist circumference, skinfold thickness, and body fat mass in 1,301 children from six European birth cohorts age 6-11 y. We estimated 77 prenatal exposures and 96 childhood exposures (cross-sectionally), including indoor and outdoor air pollutants, built environment, green spaces, tobacco smoking, and biomarkers of chemical pollutants (persistent organic pollutants, metals, phthalates, phenols, and pesticides). We used an exposure-wide association study (ExWAS) to screen all exposure-outcome associations independently and used the deletion-substitution-addition (DSA) variable selection algorithm to build a final multiexposure model. Results: The prevalence of overweight and obesity combined was 28.8%. Maternal smoking was the only prenatal exposure variable associated with higher child BMI (z-score increase of 0.28, 95% confidence interval: 0.09, 0.48, for active vs. no smoking). For childhood exposures, the multiexposure model identified particulate and nitrogen dioxide air pollution inside the home, urine cotinine levels indicative of secondhand smoke exposure, and residence in more densely populated areas and in areas with fewer facilities to be associated with increased child BMI. Child blood levels of copper and cesium were associated with higher BMI, and levels of organochlorine pollutants, cobalt, and molybdenum were associated with lower BMI. Similar results were found for the other adiposity outcomes. Discussion: This first comprehensive and systematic analysis of many suspected environmental obesogens strengthens evidence for an association of smoking, air pollution exposure, and characteristics of the built environment with childhood obesity risk. Cross-sectional biomarker results may suffer from reverse causality bias, whereby obesity status influenced the biomarker concentration. https://doi.org/10.1289/EHP5975. This study received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 308333 – the HELIX project for data collection and analyses. The HELIX program built on six existing cohorts that received previous funding, including the major ones listed below. INMA data collections were supported by grants from the Instituto de Salud Carlos III, CIBERESP, and the Generalitat de Catalunya-CIRIT. KANC was funded by the grant of the Lithuanian Agency for Science Innovation and Technology (6-04-2014_31V-66). The Norwegian Mother and Child Cohort Study (MoBa) is supported by the Norwegian Ministry of Health and the Ministry of Education and Research, National Institutes of Health (NIH)/ National Institute of Environmental Health Sciences (NIEHS) (contract no. N01-ES-75558), and NIH/NINDS (grants 1 UO1 NS 047537-01 and 2 UO1 NS 047537-06A1). The Rhea project was financially supported by European projects and the Greek Ministry of Health (Program of Prevention of Obesity and Neurodevelopmental Disorders in Preschool Children in Heraklion district, Crete, Greece: 2011–2014; “Rhea Plus,” Primary Prevention Program of Environmental Risk Factors for Reproductive Health, and Child Health: 2012–2015). M.C. received funding from Instituto de Salud Carlos III (Ministry of Economy and Competitiveness) (MS16/00128). L.C. was supported by the NIH/NIEHS grants R21ES029681, R01ES030691, R01ES029944, R01 ES030364, R21ES028903, and P30ES007048.

BACKGROUND: Adequate transplacental passage of maternal thyroid hormone is important for normal fetal growth and development. Maternal overt hypothyroidism and hyperthyroidism are associated with low birth weight but there are still important knowledge gaps regarding the impact of subclinical thyroid function test abnormalities on birth weight, in general or during the late second and third trimester of pregnancy, remains unknown. The aim of this study was to examine associations of maternal thyroid function with birth weight. METHODS: For this individual-participant data meta-analysis we searched Medline (Ovid), Embase.com, Web-of-Science, Cochrane CENTRAL and Google Scholar from inception to March 18(th) 2018, and published open invitations to join the Consortium on Thyroid and Pregnancy, to identify prospective cohort studies with data on maternal thyroid function during pregnancy and birth weight. We excluded participants with multiple pregnancies, in vitro fertilization, pre-existing thyroid disease or thyroid medication usage, miscarriages and stillbirth. Main outcomes were small for gestational age (SGA), large for gestational age (LGA) (defined by the lowest or highest 10(th) population-specific percentile of birth weight standardized to gestational age and sex, respectively) and birth weight. We analysed individual participant data using mixed-effects regression models adjusting for maternal age, body mass index, ethnicity, smoking, parity, gestational age at blood sampling, fetal sex and gestational age at birth (the latter two only in case of birth weight continuously). The study protocol was pre-registered at the International Prospective Register of Systematic Reviews (PROSPERO), number CRD42016043496. RESULTS: From 2,526 published reports, 36 cohorts met the inclusion criteria and were invited to participate of which 15 agreed and after addition of 5 unpublished datasets, a total of 20 cohorts were included. After exclusions, the study population comprised 48,145 mother-child pairs of whom 1,275 (3·1%) had subclinical hypothyroidism (increased TSH with normal FT4) and 929 (2·2%) had isolated hypothyroxinaemia (decreased FT4 with normal TSH). Maternal subclinical hypothyroidism was associated with a higher risk of SGA compared to euthyroidism (11·8% vs. 10·0% respectively, adjusted risk difference 2·4% [95% CI, 0·4 to 4·8]; odds ratio (OR) 1·24 [95% CI 1·04 to 1.48], P=0·015) and lower mean birth weight (adjusted risk difference −38g [95% CI −61 to −15], P=0·001) with a higher effect estimate for measurement in the 3(rd) trimester compared with the 1(st) or 2(nd) trimester. Isolated hypothyroxinaemia was associated with a lower risk of SGA compared to euthyroidism (7·3% vs. 10·0%, adjusted risk difference −2·9 [95% CI, −4·5 to −0·9]; OR, 0·70 [95% CI 0·55 to 0·91], P=0·007) and higher mean birth weight (difference, 45g [95% CI 18 to 73], P=0·001). Each 1-SD higher maternal TSH concentration was associated with lower birth weight (−6g [−10 to −2], per SD, P=0·003), with higher effect estimates in TPOAb-positive than TPO-negative women (P for interaction=0·10). Each 1-SD higher FT4 concentration was associated with lower birth weight (−21g [95% CI −25 to −17] per SD, P

Prenatal cadmium exposure has been associated with impaired fetal growth; much less is known about the impact during later childhood on growth and cardiometabolic traits. To elucidate the associations of prenatal cadmium exposure with child growth, adiposity, and cardiometabolic traits in 515 mother-child pairs in the Rhea Mother-Child Study cohort (Heraklion, Greece, 2007-2012), we measured urinary cadmium concentrations during early pregnancy and assessed their associations with repeated weight and height measurements (taken from birth through childhood), waist circumference, skinfold thickness, blood pressure, and serum lipid, leptin, and C-reactive protein levels at age 4 years. Adjusted linear, Poisson, and mixed-effects regression models were used, with interaction terms for child sex and maternal smoking added. Elevated prenatal cadmium levels (third tertile of urinary cadmium concentration (0.571-2.658 μg/L) vs. first (0.058-0.314 μg/L) and second (0.315-0.570 μg/L) tertiles combined) were significantly associated with a slower weight trajectory (per standard deviation score) in all children (β = -0.17, 95% confidence interval (CI): -0.32, -0.02) and a slower height trajectory in girls (β = -0.30, 95% CI: -0.52,-0.09; P for interaction = 0.025) and in children born to mothers who smoked during pregnancy (β = -0.48, 95% CI: -0.83, -1.13; P for interaction = 0.027). We concluded that prenatal cadmium exposure was associated with delayed growth in early childhood. Further research is needed to understand cadmium-related sex differences and the role of coexposure to maternal smoking during early pregnancy. The Rhea Mother-Child Cohort Study was financially supported by European Union projects (FP6-2003-Food-3-A NewGeneris, Food-CT-2006-036224 Hiwate, FP7/2007- 2011-GA-211250 ESCAPE Project, FP7-2008-226756 Envirogenomarkers, FP7-HEALTH-2009 single-stage 241604 CHICOS, and FP7-ENV.2008.1.2.1.6 proposal 226285 ENRIECO) and the Greek Ministry of Health (Program of Prevention of Obesity and Neurodevelopmental Disorders in Preschool Children, Heraklion District, Crete, Greece, 2011–2014; and “Rhea Plus”: Primary Prevention Program of Environmental Risk Factors for Reproductive Health and Child Health, 2012–2015). The present study was also funded by the Karolinska Institutet, the Swedish Research Council Formas (project 210-2013-751), and the Swedish Research Council (project 2015-03655).

Background: DNA methylation profiles associated with childhood asthma might provide novel insights into disease pathogenesis. We did an epigenome-wide association study to assess methylation profiles associated with childhood asthma. Methods: We did a large-scale epigenome-wide association study (EWAS) within the Mechanisms of the Development of ALLergy (MeDALL) project. We examined epigenome-wide methylation using Illumina Infinium Human Methylation450 BeadChips (450K) in whole blood in 207 children with asthma and 610 controls at age 4–5 years, and 185 children with asthma and 546 controls at age 8 years using a cross-sectional case-control design. After identification of differentially methylated CpG sites in the discovery analysis, we did a validation study in children (4–16 years; 247 cases and 2949 controls) from six additional European cohorts and meta-analysed the results. We next investigated whether replicated CpG sites in cord blood predict later asthma in 1316 children. We subsequently investigated cell-type-specific methylation of the identified CpG sites in eosinophils and respiratory epithelial cells and their related gene-expression signatures. We studied cell-type specificity of the asthma association of the replicated CpG sites in 455 respiratory epithelial cell samples, collected by nasal brushing of 16-year-old children as well as in DNA isolated from blood eosinophils (16 with asthma, eight controls [age 2–56 years]) and compared this with whole-blood DNA samples of 74 individuals with asthma and 93 controls (age 1–79 years). Whole-blood transcriptional profiles associated with replicated CpG sites were annotated using RNA-seq data of subsets of peripheral blood mononuclear cells sorted by fluorescence-activated cell sorting. Findings: 27 methylated CpG sites were identified in the discovery analysis. 14 of these CpG sites were replicated and passed genome-wide significance (p

Purpose: The study assessed whether diet and adherence to cancer prevention guidelines during pregnancy were associated with micronucleus (MN) frequency in mothers and newborns. MN is biomarkers of early genetic effects that have been associated with cancer risk in adults. Methods: A total of 188 mothers and 200 newborns from the Rhea cohort (Greece) were included in the study. At early-mid pregnancy, we conducted personal interviews and a validated food frequency questionnaire was completed. With this information, we constructed a score reflecting adherence to the World Cancer Research Fund/American Institute for Cancer Research cancer prevention guidelines on diet, physical activity and body fatness. At delivery, maternal and/or cord blood was collected to measure DNA and hemoglobin adducts of dietary origin and frequencies of MN in binucleated and mononucleated T lymphocytes (MNBN and MNMONO). Results: In mothers, higher levels of red meat consumption were associated with increased MNBN frequency [2nd tertile IRR = 1.34 (1.00, 1.80), 3rd tertile IRR = 1.33 (0.96, 1.85)] and MNMONO frequency [2nd tertile IRR = 1.53 (0.84, 2.77), 3rd tertile IRR = 2.69 (1.44, 5.05)]. The opposite trend was observed for MNBN in newborns [2nd tertile IRR = 0.64 (0.44, 0.94), 3rd tertile IRR = 0.68 (0.46, 1.01)], and no association was observed with MNMONO. Increased MN frequency in pregnant women with high red meat consumption is consistent with previous knowledge. Conclusions: Our results also suggest exposure to genotoxics during pregnancy might affect differently mothers and newborns. The predictive value of MN as biomarker for childhood cancer, rather than adulthood, remains unclear. With few exceptions, the association between maternal carcinogenic exposures during pregnancy and childhood cancer or early biologic effect biomarkers remains poorly understood. The Rhea cohort was funded by the following European projects NewGeneris (FP-6-FOOD-CT-2005-016320), ESCAPE (FP7-2007-211250), HiWATE (FP-6-FOOD-CT-2006-036224), Envirogenomarkers (FP7-2008-ENV-1.2.1.4), CHICOS (FP7-2009-GA 241604), and ENRIECO (FP7-2008-GA 226285). COG holds a Sara Borrell postdoctoral fellowship awarded from the Carlos III National Institute of Health (CD13/00072). MP held a Juan de la Cierva postdoctoral fellowship awarded from the Spanish Ministry of Ministry of Economy and Competitiveness (JCI-2011-09479). DFM received support from the Italian Ministry of Health, 5x1000 Grant-2011.

Background Evidence for an infectious origin of obesity is emerging. We explored whether common viruses were associated with obesity and metabolic traits. Methods We used cross-sectional (n=674) and prospective (n=440) data from children participating at the 4 and 6 years of age follow-up in the Rhea birth cohort. Presence of IgG antibodies to ten polyomaviruses (BKPyV, JCPyV, KIPyV, WUPyV, HPyV6, HPyV7, TSPyV, MCPyV, HPyV9, and HPyV10) and four herpesviruses (EBV, CMV, HSV-1, and HSV-2) were measured at age 4. Body mass index, waist circumference, and skinfold thickness were measured at age 4 and 6. Data on serum lipids, leptin, and adiponectin were also available. Multivariable linear regression models were used to explore the associations. Results At 4 years of age, seroprevalence to polyomaviruses ranged from 21.0% for HPyV9 to 82.0% for HPyV10. Seroprevalence for EBV, CMV, HSV-1, and HSV-2 was 53.0%, 26.0%, 3.6%, and 1.5% respectively. BKPyV seropositivity was associated with lower BMI SD score at age 4 [-0.21 (95% CI: -0.39, -0.03)] and 6 [-0.27 (95% CI:-0.48, -0.05)], waist circumference at age 4 [-1.12 cm (95% CI: -2.10, -0.15)] and 6 [-1.73 cm (95% CI: -3.33, -0.12)], sum of four skinfolds [-2.97 mm (95% CI: -5.70, -0.24)], and leptin levels at age 4 [ratio of geometric means, 0.83 (95% CI: 0.70, 0.98)]. CMV seropositivity was associated with higher BMI SD score at age 4 [0.28 (95% CI: 0.11, 0.45)] and 6 [0.24 (95% CI: 0.03, 0.45)] and sum of four skinfolds at age 6 [4.75 mm (95% CI: 0.67, 8.83)]. Having "2-3 herpesviruses infections" (versus "0 herpesvirus infections") was associated with higher BMI SD score [0.32, (95% CI: 0.12, 0.53)], waist circumference [1.22 cm (95% CI: 0.13, 2.31)], and sum of four skinfolds [3.26 mm (95% CI: 0.18, 6.35)] at age 4. Polyomaviruses burden was not associated with outcomes. Conclusions A higher herpesviruses burden and CMV seropositivity were associated with obesity traits in childhood.

BACKGROUND Vitamin D may modulate adipogenesis. However, limited studies have investigated the effect of maternal vitamin D during pregnancy on offspring adiposity or cardiometabolic parameters with inconclusive results. OBJECTIVES The objective of this study is to examine the association of maternal 25(OH)-vitamin D [25(OH)D] status with offspring obesity and cardiometabolic characteristics in 532 mother-child pairs from the prospective pregnancy cohort Rhea in Crete, Greece. METHODS Maternal 25(OH)D concentrations were measured at the first prenatal visit (mean: 14 weeks, SD: 4). Child outcomes included body mass index standard deviation score, waist circumference, skin-fold thickness, blood pressure and serum lipids at ages 4 and 6 years. Body fat percentage was also measured at 6 years. Body mass index growth trajectories from birth to 6 years were estimated by mixed effects models with fractional polynomials of age. Adjusted associations were obtained via multivariable linear regression analyses. RESULTS About two-thirds of participating mothers had 25(OH)D concentrations

Background: It has been suggested that prenatal exposure to n-3 long-chain fatty acids protects against asthma and other allergy-related diseases later in childhood. The extent to which fish intake in pregnancy protects against child asthma and rhinitis symptoms remains unclear. We aimed to assess whether fish and seafood consumption in pregnancy is associated with childhood wheeze, asthma and allergic rhinitis. Methods: We pooled individual data from 60 774 mother-child pairs participating in 18 European and US birth cohort studies. Information on wheeze, asthma and allergic rhinitis prevalence was collected using validated questionnaires. The time periods of interest were: infancy (0-2 years), preschool age (3-4 years), and school age (5-8 years). We used multivariable generalized models to assess associations of fish and seafood (other than fish) consumption during pregnancy with child respiratory outcomes in cohort-specific analyses, with subsequent random-effects meta-analyses. Results: The median fish consumption during pregnancy ranged from 0.44 times/week in The Netherlands to 4.46 times/week in Spain. Maternal fish intake during pregnancy was not associated with offspring wheeze symptoms in any age group nor with the risk of child asthma [adjusted meta-analysis relative risk (RR) per 1-time/week = 1.01, 95% confidence interval 0.97-1.05)] and allergic rhinitis at school age (RR = 1.01, 0.99-1.03). These results were consistently found in further analyses by type of fish and seafood consumption and in sensitivity analyses. Conclusion: We found no evidence supporting a protective association of fish and seafood consumption during pregnancy with offspring symptoms of wheeze, asthma and allergic rhinitis from infancy to mid childhood. This work was supported by the European Community’s Seventh Framework Program [EU- FP7- HEALTH-2009-single-stage-241604]. Details of funding per cohort are available at IJE online.

ObjectivesSeveral population-based studies on systemic lupus erythematosus (SLE) have been reported, yet community-based, individual-case validated, comprehensive reports are missing. We studied the SLE epidemiology and burden on the island of Crete during 1999–2013.MethodsMultisource case-finding included patients ≥15 years old. Cases were ascertained by the ACR 1997, SLICC 2012 criteria and rheumatologist diagnosis, and validated through synthesis of medical charts, administrative and patient-generated data.ResultsOverall age-adjusted/sex-adjusted incidence was 7.4 (95% CI 6.8 to 7.9) per 100 000 persons/year, with stabilising trends in women but increasing in men, and average (±SD) age of diagnosis at 43 (±15) years. Adjusted and crude prevalence (December 2013) was 123.4 (113.9 to 132.9) and 143 (133 to 154)/105 (165/105 in urban vs 123/105 in rural regions, pConclusionsBy the use of a comprehensive methodology, we describe the full spectrum of SLE from the community to tertiary care, with almost half of the cases having mild disease, yet with significant damage accrual. SLE is not rare, affects predominantly middle-aged women and is increasingly recognised in men. Neuropsychiatric disease is an emerging frontier in lupus prevention and care.

BACKGROUND & AIMS: Vitamin D deficiency is common among pregnant women and may be associated with several adverse health outcomes including cancer. Micronuclei frequency is a biomarker of early genetic effects and has been used to examine the association between genotoxic exposures and cancer. We examined maternal vitamin D levels during pregnancy in associations with micronuclei frequency in maternal blood and in cord blood. METHODS: 173 mothers and 171 newborns born between 2007 and 2008 in Heraklion (Crete, Greece) were included in the study. Between 14th and 18th weeks of gestation we collected information on maternal diet using food frequency questionnaires (FFQs). We measured maternal serum concentrations of 25-hydroxyvitamin D [25(OH)D] between the first and second trimester of pregnancy. We estimated dietary vitamin D intake using information from FFQ. After delivery we collected cord blood and maternal peripheral blood. We used the cytokinesis-block micronucleus (CBMN) assay to assess the frequencies of micronucleated cells in binucleated T lymphocytes (MNBN). RESULTS: Maternal insufficient serum levels of 25(OH)D (

SummaryBackground Emerging experimental evidence suggests that air pollution may contribute to development of obesity and diabetes, but studies of children are limited. Objectives We hypothesized that pollution effects would be magnified after bariatric surgery for treatment of obesity, reducing benefits of surgery. Methods In 75 obese adolescents, excess weight loss (EWL), high-density lipoprotein (HDL) cholesterol, triglycerides, alkaline phosphatase (ALP) and hemoglobin A1c (HbA1c) were measured prospectively at baseline and following laparoscopic adjustable gastric banding (LAGB). Residential distances to major roads and the average two-year follow-up exposure to particulate matter

Background Toxicant-associated steatohepatitis has been described in adults but less is known regarding the role of toxicants in liver disease of children. Perfluoroalkyl substances (PFAS) cause hepatic steatosis in rodents, but few previous studies have examined PFAS effects on severity of liver injury in children. Objectives We aimed to examine the relationship of PFAS to histologic severity of nonalcoholic fatty liver disease (NAFLD) in children. Methods Seventy-four children with physician-diagnosed NAFLD were recruited from Children’s Healthcare of Atlanta between 2007 and 2015. Biopsy-based liver histological features were scored for steatosis, lobular and portal inflammation, ballooning, and fibrosis. Plasma concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonic acid (PFHxS), and untargeted plasma metabolomic profiling, were determined using liquid chromatography with high-resolution mass spectrometry. A metabolome-wide association study coupled with pathway enrichment analysis was performed to evaluate metabolic dysregulation associated with PFAS. A structural integrated analysis was applied to identify latent clusters of children with more severe form of NAFLD based on their PFAS levels and metabolite pattern. Results Patients were 7–19 years old, mostly boys (71%), Hispanic (51%), and obese (85%). The odds of having nonalcoholic steatohepatitis (NASH), compared to children with steatosis alone, was significantly increased with each interquartile range (IQR) increase of PFOS (OR: 3.32, 95% CI: 1.40–7.87) and PFHxS (OR: 4.18, 95% CI: 1.64–10.7). Each IQR increase of PFHxS was associated with increased odds for liver fibrosis (OR: 4.44, 95% CI: 1.34–14.8), lobular inflammation (OR: 2.87, 95% CI: 1.12–7.31), and higher NAFLD activity score (β coefficient 0.46; 95% CI: 0.03, 0.89). A novel integrative analysis identified a cluster of children with NASH, characterized by increased PFAS levels and altered metabolite patterns including higher plasma levels of phosphoethanolamine, tyrosine, phenylalanine, aspartate and creatine, and decreased plasma levels of betaine. Conclusions Ηigher PFAS exposure was associated with more severe disease in children with NAFLD. PFAS may be an important toxicant contributing to NAFLD progression; however larger, longitudinal studies are warranted to confirm these findings.

Key Points Question Is fish consumption during pregnancy associated with benefits for the metabolic health of children? Findings In this cohort study of 805 mothers and their singleton offspring, moderate fish consumption during pregnancy was associated with the downregulation of inflammation and improvements in the metabolic profile of children; high mercury exposure during pregnancy had the opposite associations. Meaning The results of this study suggest that fish consumption consistent with current recommendations during pregnancy was associated with improvements in the metabolic health of children., Importance The balance of mercury risk and nutritional benefit from fish intake during pregnancy for the metabolic health of offspring to date is unknown. Objective To assess the associations of fish intake and mercury exposure during pregnancy with metabolic syndrome in children and alterations in biomarkers of inflammation in children. Design, Setting, and Participants This population-based prospective birth cohort study used data from studies performed in 5 European countries (France, Greece, Norway, Spain, and the UK) between April 1, 2003, and February 26, 2016, as part of the Human Early Life Exposome (HELIX) project. Mothers and their singleton offspring were followed up until the children were aged 6 to 12 years. Data were analyzed between March 1 and August 2, 2019. Exposures Maternal fish intake during pregnancy (measured in times per week) was assessed using validated food frequency questionnaires, and maternal mercury concentration (measured in micrograms per liter) was assessed using maternal whole blood and cord blood samples. Main Outcomes and Measures An aggregate metabolic syndrome score for children was calculated using the z scores of waist circumference, systolic and diastolic blood pressures, and levels of triglyceride, high-density lipoprotein cholesterol, and insulin. A higher metabolic syndrome score (score range, −4.9 to 7.5) indicated a poorer metabolic profile. Three protein panels were used to measure several cytokines and adipokines in the plasma of children. Results The study included 805 mothers and their singleton children. Among mothers, the mean (SD) age at cohort inclusion or delivery of their infant was 31.3 (4.6) years. A total of 400 women (49.7%) had a high educational level, and 432 women (53.7%) were multiparous. Among children, the mean (SD) age was 8.4 (1.5) years (age range, 6-12 years). A total of 453 children (56.3%) were boys, and 734 children (91.2%) were of white race/ethnicity. Fish intake consistent with health recommendations (1 to 3 times per week) during pregnancy was associated with a 1-U decrease in metabolic syndrome score in children (β = −0.96; 95% CI, −1.49 to −0.42) compared with low fish consumption (, This cohort study used data from the Human Early Life Exposome (HELIX) project, a collaboration of 5 European birth cohort studies, to examine the associations of maternal fish consumption and mercury exposure during pregnancy with metabolic health and inflammatory biomarkers in children.

Study objectives: The objective of this study was to evaluate the association between gestational sleep deprivation and childhood adiposity and cardiometabolic profile. Methods: Data were used from two population-based birth cohorts (Rhea study and Amsterdam Born Children and their Development study). A total of 3,608 pregnant women and their children were followed up until the age of 11 years. Gestational sleep deprivation was defined as 6 or fewer hours of sleep per day, reported by questionnaire. The primary outcomes included repeated measures of body mass index (BMI), waist circumference, body fat, serum lipids, systolic and diastolic blood pressure (DBP) levels in childhood. We performed a pooled analysis with adjusted linear mixed effect and Cox proportional hazards models. We tested for mediation by birthweight, gestational age, and gestational diabetes. Results: Gestational sleep deprivation was associated with higher BMI (beta; 95% CI: 0.7; 0.4, 1.0 kg/m2) and waist circumference (beta; 95% CI: 0.9; 0.1, 1.6 cm) in childhood, and increased risk for overweight or obesity (HR; 95% CI: 1.4; 1.1, 2.0). Gestational sleep deprivation was also associated with higher offspring DBP (beta; 95% CI: 1.6; 0.5, 2.7 mmHg). The observed associations were modified by sex (all p-values for interaction < 0.05); and were more pronounced in girls. Gestational diabetes and shorter gestational age partly mediated the seen associations. Conclusions: This is the first study showing that gestational sleep deprivation may increase offspring's adiposity and blood pressure, while exploring possible mechanisms. Attention to glucose metabolism and preterm birth might be extra warranted in mothers with gestational sleep deprivation. We are thankful to all the mothers, fathers, and children who participated in the Rhea cohort and Amsterdam Born Children and their Development cohort. The ABCD study has been supported by grants from The Netherlands Organisation for Health Research and Development (ZonMW) and The Netherlands Heart Foundation. Research time of MH was supported by the municipal Amsterdam Healthy Weight Program (Amsterdamse Aanpak Gezond Gewicht). The Rhea project was financially supported by European projects (EU FP6-2003-Food-3-NewGeneris, EU FP6. STREP Hiwate, EU FP7 ENV.2007.1.2.2.2. Project No 211250 Escape, EU FP7-2008-ENV-1.2.1.4 Envirogenomarkers, EU FP7-HEALTH-2009-single stage CHICOS, EU FP7 ENV.2008.1.2.1.6. Proposal No 226285 ENRIECO, EUFP7-HEALTH-2012 Proposal No 308333 HELIX, FP7 European Union project, No. 264357 MeDALL), and the Ministry of health and social solidarity, Greece (Program of Prevention of obesity and neurodevelopmental disorders in preschool children, in Heraklion district, Crete, Greece: 2011–2014; Rhea Plus: Primary Prevention Program of Environmental Risk Factors for Reproductive Health, and Child Health: 2012–15). Dr Lida Chatzi was supported by the National Institute of Environmental Health Sciences (NIEHS/National Institutes of Health (NIH)) grants: R21ES029681, R01ES030691, R01ES029944, R01 ES030364, R21ES028903, and P30ES007048, and by NIH (UH3OD023287). The study was also supported by Seventh Framework Programme and Hartstichting.

Background: Pregnant women and children are especially vulnerable to exposures to food contaminants, and a balanced diet during these periods is critical for optimal nutritional status. Objectives: Our objective was to study the association between diet and measured blood and urinary levels of environmental contaminants in mother-child pairs from six European birth cohorts (n = 818 mothers and 1,288 children). Methods: We assessed the consumption of seven food groups and the blood levels of organochlorine pesticides, polybrominated diphenyl ethers, polychlorinated biphenyls (PCBs), per- and polyfluoroalkyl substances (PFAS), and heavy metals and urinary levels of phthalate metabolites, phenolic compounds, and organophosphate pesticide (OP) metabolites. Organic food consumption during childhood was also studied. We applied multivariable linear regressions and targeted maximum likelihood based estimation (TMLE). Results: Maternal high (≥ 4times/week) versus low (< 2times/week) fish consumption was associated with 15% higher PCBs [geometric mean (GM) ratio = 1.15; 95% confidence interval (CI): 1.02, 1.29], 42% higher perfluoroundecanoate (PFUnDA) (GMratio = 1.42; 95% CI: 1.20, 1.68), 89% higher mercury (Hg) (GMratio = 1.89; 95% CI: 1.47, 2.41) and a 487% increase in arsenic (As) (GMratio = 4.87; 95% CI: 2.57, 9.23) levels. In children, high (≥ 3times/week) versus low (< 1.5times/week) fish consumption was associated with 23% higher perfluorononanoate (PFNA) (GMratio = 1.23; 95% CI: 1.08, 1.40), 36% higher PFUnDA (GMratio = 1.36; 95% CI: 1.12, 1.64), 37% higher perfluorooctane sulfonate (PFOS) (GMratio = 1.37; 95% CI: 1.22, 1.54), and >200% higher Hg and As [GMratio = 3.87 (95% CI: 1.91, 4.31) and GMratio = 2.68 (95% CI: 2.23, 3.21)] concentrations. Using TMLE analysis, we estimated that fish consumption within the recommended 2-3 times/week resulted in lower PFAS, Hg, and As compared with higher consumption. Fruit consumption was positively associated with OP metabolites. Organic food consumption was negatively associated with OP metabolites. Discussion: Fish consumption is related to higher PFAS, Hg, and As exposures. In addition, fruit consumption is a source of exposure to OPs. https://doi.org/10.1289/EHP5324. The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 308,333, the Human Early Life Exposome (HELIX) project. The Environment and Childhood (INMA) Sabadell cohort and biomarker measurements were funded by grants from Instituto de Salud Carlos III [Red INMA G03/176; CB06/02/0041; PI041436; PI081151 including Federación Española de Enfermedades Raras (FEDER) funds; PI12/01,890 including FEDER funds; CP13/00,054 including FEDER funds], CIBERESP, Generalitat de Catalunya-Consell Interdepartamental de Recerca i Innovació Tecnològica (CIRIT) 1999SGR 00,241, Generalitat de Catalunya-Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR) (2009 SGR 501, 2014 SGR 822), Fundació La marató de TV3 (090,430), Spanish Ministry of Economy and Competitiveness (SAF2012-32,991 including FEDER funds). The Norwegian Mother, Father and Child Cohort Study is supported by the Norwegian Ministry of Health and Care Services and the Ministry of Education and Research, National Institutes of Health, National Institute of Neurological Disorders and Stroke (NIH/NINDS; grants UO1 NS 047,537-01 and UO1 NS 047,537-06A1). The Rhea cohort was financially supported by European projects [EU FP6-2003-Food-3-NewGeneris, EU FP6 STREP Hiwate, EU FP7 ENV.2007.1.2.2.2. (project no. 211,250 Escape), EU FP7-2008-ENV-1.2.1.4 Envirogenomarkers, EU FP7-HEALTH-2009-single stage CHICOS, EU FP7 ENV.2008.1.2.1.6. (proposal no. 226,285 ENRIECO), EU- FP7-HEALTH-2012 (proposal no. 308,333 HELIX)] and by the Greek Ministry of Health (Program of Prevention of Obesity and Neurodevelopmental Disorders in Preschool Children, in Heraklion District, Crete, Greece: 2011–2014; “Rhea Plus”: Primary Prevention Program of Environmental Risk Factors for Reproductive Health, and Child Health: 2012–15). The Lithuanian Kaunas Cohort (KANC) supported by the Lithuanian Agency for Science Innovation and Technology (No. 31V-77). M.C. received funding from Instituto de Salud Carlos III (Ministry of Economy and Competitiveness) (MS16/00,128). E.P. and A.L.B. received funding from the Norwegian Research Council (Project No. 268,465). R.R.C.M. and J.W. were supported by the National Institute for Health Research (NIHR) Collaborations for Leadership in Applied Health Research and Care (CLAHRC) Yorkshire and Humber (IS-CLA-0113-10,020; http://www.clahrc-yh.nihr.ac.uk). L.C. received funding from the NIH (P30ES007048) and National Institute of Environmental Health Sciences (NIEHS R21ES02890).

Prenatal exposure to phenolic compounds, widely used in many consumer products, can alter lung development and increase the risk of respiratory disorders in the offspring. However, evidence is scarce and mostly focused on bisphenol-A (BPA), although there are other substitutes that could also interfere with the developing respiratory system. We aim to estimate the association between exposure to 5 phenols during pregnancy (BPA, BPAF, BPB, BPF, and BPS) and lung function, wheeze, and asthma in school-age children. We included 2685 mother-child pairs from 8 European birth cohorts. Phenols concentrations were determined in urinary maternal samples collected during pregnancy (1999-2010). Between 6 and 10 years of age, spirometry was performed, and wheeze and asthma were assessed from questionnaires. Adjusted multivariable linear regression and logistic regression models were used to assess the associations. We performed meta-analyses of cohort-specific estimates. We observed widespread prenatal BPA exposure with 79% of the samples above detectable limits; the other phenols were detected in fewer samples. Median BPA concentrations ranged from 1.04 to 9.54 ng/g of creatinine. Increasing BPA concentrations during pregnancy tended to be associated with lower FVC and FEV1 and were associated with increased odds of wheezing between ages 6 and 10 years (adjusted odds ratio=1.09; 95% CI=0.96, 1.24), but not with asthma. Final results including associations of the other phenols with respiratory outcomes including wheezing patterns from birth will be presented. Preliminary results showed that prenatal exposure to BPA might increase the odds of wheezing in school-age children.

Post-partum depression (PPD) is a severe psychiatric disorder affecting ∼15% of young mothers. Early life stressful conditions in periconceptual, fetal and early infant periods or exposure to maternal psychiatric disorders, have been linked to adverse childhood outcomes interfering with physiological, cognitive and emotional development. The molecular mechanisms of PPD are not yet fully understood. Unraveling the molecular underpinnings of PPD will allow timely detection and establishment of effective therapeutic approaches. To investigate the underlying molecular correlates of PPD in peripheral material, we compared the serum metabolomes of an in detail characterized group of mothers suffering from PPD and a control group of mothers, all from Heraklion, Crete in Greece. Serum samples were analyzed by a mass spectrometry platform for targeted metabolomics, based on selected reaction monitoring (SRM), which measures the levels of up to 300 metabolites. In the PPD group, we observed increased levels of glutathione-disulfide, adenylosuccinate, and ATP, which associate with oxidative stress, nucleotide biosynthesis and energy production pathways. We also followed up the metabolomic findings in a validation cohort of PPD mothers and controls. To the very best of our knowledge, this is the first metabolomic serum analysis in PPD. Our data show that molecular changes related to PPD are detectable in peripheral material, thus paving the way for additional studies in order to shed light on the molecular correlates of PPD.

Background: Telomere length is a molecular marker of biological aging. Objective: Here we investigated whether early-life exposure to residential air pollution was associated with leukocyte telomere length (LTL) at 8 y of age. Methods: In a multicenter European birth cohort study, HELIX (Human Early Life Exposome) ([Formula: see text]), we estimated prenatal and 1-y childhood exposure to nitrogen dioxide ([Formula: see text]), particulate matter with aerodynamic diameter [Formula: see text] ([Formula: see text]), and proximity to major roads. Average relative LTL was measured using quantitative real-time polymerase chain reaction (qPCR). Effect estimates of the association between LTL and prenatal, 1-y childhood air pollution, and proximity to major roads were calculated using multiple linear mixed models with a random cohort effect and adjusted for relevant covariates. Results: LTL was inversely associated with prenatal and 1-y childhood [Formula: see text] and [Formula: see text] exposures levels. Each standard deviation (SD) increase in prenatal [Formula: see text] was associated with a [Formula: see text] (95% CI: [Formula: see text], [Formula: see text]) change in LTL. Prenatal [Formula: see text] was nonsignificantly associated with LTL ([Formula: see text] per SD increase; 95% CI: [Formula: see text], 0.6). For each SD increment in 1-y childhood [Formula: see text] and [Formula: see text] exposure, LTL shortened by [Formula: see text] (95% CI: [Formula: see text], [Formula: see text]) and [Formula: see text] (95% CI: [Formula: see text], 0.1), respectively. Each doubling in residential distance to nearest major road during childhood was associated with a 1.6% (95% CI: 0.02, 3.1) lengthening in LTL. Conclusion: Lower exposures to air pollution during pregnancy and childhood were associated with longer telomeres in European children at 8 y of age. These results suggest that reductions in traffic-related air pollution may promote molecular longevity, as exemplified by telomere length, from early life onward. https://doi.org/10.1289/EHP4148. The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 308333 (the HELIX project) and from Instituto de Salud Carlos III (PI15/00118, including The European Regional Development Fund (FEDER)). T.S.N. was funded by the EU Program “Ideas” (ERC-2012-StG 310898). ISGlobal is a member of the Centres de Recerca de Catalunya (CERCA) Programme, Generalitat de Catalunya. We are grateful to all the participating families in the six countries who took part in this study.

Background: Human exposure to environmental chemical contaminants at critical periods of development can lead to lifelong health consequences. Traditionally, socioeconomically disadvantaged groups are thought to experience higher contaminant exposures; however, this relationship may not hold for all contaminants.Methods: Using data from six European birth cohorts (1301 mother-child pairs), we determined biomarkers of exposure to 41 contaminants in biological samples from children (6-12 years) and their mothers during pregnancy, including organochlorine compounds (OCs), polybrominated diphenyl ethers (PBDEs), per- and polyfluoroalkyl substances (PFASs), metals, phthalate metabolites, phenols, and organophosphate (OP) pesticide metabolites. We analyzed these biomarkers with several socioeconomic position (SEP) indicators (maternal education, employment status and family affluence scale).Results: Higher SEP was associated with higher concentrations of several chemicals during pregnancy, including certain PFASs, mercury, arsenic, several phenols, and OP pesticides. Similarly, childhood concentrations of OCs, PFASs, mercury, arsenic, and bisphenol A were higher in higher SEP groups. Conversely, cadmium exposure during pregnancy and exposure to lead and phthalate metabolites in childhood were higher in lower SEP. Principal components representing multiple pollutant exposures showed similar association with SEP.Conclusions: This study demonstrates that environmental chemical contaminant exposure during fetal and childhood life is not exclusively associated to lower SEP and that for several contaminants higher SEP groups incur higher exposure levels.

Background The burden of childhood and adult obesity disproportionally affects Hispanic and African-American populations in the US, and these groups as well as populations with lower income and education levels are disproportionately affected by environmental pollution. Pregnancy is a critical developmental period where maternal exposures may have significant impacts on infant and childhood growth as well as the future health of the mother. We initiated the “Maternal And Developmental Risks from Environmental and Social Stressors (MADRES)” cohort study to address critical gaps in understanding the increased risk for childhood obesity and maternal obesity outcomes among minority and low-income women in urban Los Angeles. Methods The MADRES cohort is specifically examining whether pre- and postpartum environmental exposures, in addition to exposures to psychosocial and built environment stressors, lead to excessive gestational weight gain and postpartum weight retention in women and to perturbed infant growth trajectories and increased childhood obesity risk through altered psychological, behavioral and/or metabolic responses. The ongoing MADRES study is a prospective pregnancy cohort of 1000 predominantly lower-income, Hispanic women in Los Angeles, CA. Enrollment in the MADRES cohort is initiated prior to 30 weeks gestation from partner community health clinics in Los Angeles. Cohort participants are followed through their pregnancies, at birth, and during the infant’s first year of life through a series of in-person visits with interviewer-administered questionnaires, anthropometric measurements and biospecimen collection as well as telephone interviews conducted with the mother. Discussion In this paper, we outline the study rationale and data collection protocol for the MADRES cohort, and we present a profile of demographic, health and exposure characteristics for 291 participants who have delivered their infants, out of 523 participants enrolled in the study from November 2015 to October 2018 from four community health clinics in Los Angeles. Results from the MADRES cohort could provide a powerful rationale for regulation of targeted chemical environmental components, better transportation and urban design policies, and clinical recommendations for stress-coping strategies and behavior to reduce lifelong obesity risk. Electronic supplementary material The online version of this article (10.1186/s12884-019-2330-7) contains supplementary material, which is available to authorized users.

Background Evidence suggests a complex interplay between infections and allergic diseases. Objective To explore the association of 14 common viruses with eczema, asthma, and rhinoconjunctivitis in childhood. Methods We used cross-sectional (n = 686) and prospective (n = 440) data from children participating in the Rhea birth cohort. Immunoglobulin G to polyomaviruses (BK polyomavirus, JC polyomavirus, KI polyomavirus [KIPyV], WU polyomavirus [WUPyV], human polyomavirus 6, human polyomavirus 7, Trichodysplasia spinulosa polyomavirus, Merkel cell polyomavirus, human polyomavirus 9, and human polyomavirus 10) and herpesviruses (Epstein-Barr virus, Cytomegalovirus, Herpes simplex virus-1, Herpes simplex virus-2) were measured at age 4 years by fluorescent bead-based multiplex serology. Definitions of eczema, asthma, and rhinoconjunctivitis at ages 4 and 6 years were based on questionnaires. Mediation of the associations by immune biomarkers was tested. Results Less likely to have eczema at age 4 years were KIPyV-seropositive (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.27-0.82) and human polyomavirus 6 (OR, 0.44; 95% CI, 0.26-0.73) compared with their seronegative counterparts. Seropositivity to Epstein-Barr virus was negatively associated with eczema at age 4 years (OR, 0.39; 95% CI, 0.22-0.67) and 6 years (OR, 0.50; 95% CI, 0.25-0.99). Children with a higher burden of herpesviruses or of skin polyomaviruses had the lowest odds of eczema at age 4 years. Higher odds for asthma at age 4 years were found for WUPyV-seropositive children (OR, 3.98; 95% CI, 1.38-11.51), and for children seropositive to both respiratory polyomaviruses (KIPyV and WUPyV) (OR, 7.35; 95% CI, 1.66-32.59) compared with children seronegative to both. No associations were observed for rhinoconjunctivitis. There was no evidence of mediation by immune biomarkers. Conclusion A heterogeneous pattern of infections and allergic diseases was observed with common infections associated with a decreased eczema risk and an increased asthma risk in children.

SummaryBackground In adults, adherence to the Mediterranean diet has been inversely associated with cardiovascular risk, but the extent to which diet in pregnancy is associated with offspring adiposity is unclear. We aimed to investigate the association between adherence to Mediterranean diet in pregnancy and offspring cardiometabolic traits in two pregnancy cohorts. Methods We studied 997 mother–child pairs from Project Viva in Massachusetts, USA, and 569 pairs from the Rhea study in Crete, Greece. We estimated adherence to the Mediterranean diet with an a priori defined score (MDS) of nine foods and nutrients (0 to 9). We measured child weight, height, waist circumference, skin-fold thicknesses, blood pressure, and blood levels of lipids, c-reactive protein and adipokines in mid-childhood (median 7.7 years) in Viva, and in early childhood (median 4.2 years) in Rhea. We calculated cohort-specific effects and pooled effects estimates with random-effects models for cohort and child age. Results In Project Viva, the mean (SD, standard deviation) MDS was 2.7 (1.6); in Rhea it was 3.8 (1.7). In the pooled analysis, for each 3-point increment in the MDS, offspring BMI z-score was lower by 0.14 units (95% CI, −0.15 to −0.13), waist circumference by 0.39 cm (95% CI, −0.64 to −0.14), and the sum of skin-fold thicknesses by 0.63 mm (95% CI, −0.98 to −0.28). We also observed lower offspring systolic (−1.03 mmHg; 95% CI, −1.65 to −0.42) and diastolic blood pressure (−0.57 mmHg; 95% CI, −0.98 to −0.16). Conclusion Greater adherence to Mediterranean diet during pregnancy may protect against excess offspring cardiometabolic risk.

Background: Persistent organic pollutants (POPs) are a group of diverse substances, including polychlorinated biphenyls (PCBs) and organochlorine pesticides that are resistant to biodegradation and ubiquitously present in our environment. Exposure to endocrine disrupting chemicals such as POPs has been linked to type 2 diabetes and metabolic disturbances in epidemiological and animal studies, but little is known about POPs exposure during pregnancy and the development of gestational diabetes mellitus (GDM). The purpose of this study was to determine the extent to which exposure to current low levels of different POPs in the first trimester of pregnancy is associated with GDM risk in 939 women from the “Rhea” pregnancy cohort in Crete, Greece. Methods: Concentrations of several PCBs, dichlorodiphenyldichloroethene (DDE), and hexachlorobenzene (HCB) were determined in first trimester maternal serum by triple quadrupole mass spectrometry. We defined total PCBs as the sum of all congeners, nondioxin-like PCBs as the sum of PCB 153, 138, 170 and 180, and dioxin-like PCBs as the sum of PCB 118 and 156. Pregnant women were screened for gestational diabetes mellitus (GDM) between 24 and 28 weeks of gestation, and GDM was defined by the criteria proposed by Carpenter and Coustan. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression models. Results: Of the 939 women, 68 (7%) developed GDM. Serum concentrations of POPs were higher in women with GDM. Women in the medium and high tertiles of PCBs had 3.90 (95% CI: 1.37, 11.06) and 3.60 (95% CI: 1.14, 11.39) fold respectively higher odds of developing GDM compared to women in the lowest tertile of PCB exposure after adjusting for pre-pregnancy BMI and several other confounders. Odds of GDM for women in the medium and high tertiles of dioxin-like PCBs was 5.63 (95% CI: 1.81, 17.51) and 4.71 (95% CI: 1.38, 16.01) and for nondioxin-like PCBs 2.36 (95% CI: 0.89, 6.23) and 2.26 (95% CI: 0.77, 6.68) respectively. Prenatal DDE and HCB exposure were not significantly associated GDM risk. Conclusions: These findings suggest that women with high PCBs levels in early pregnancy had higher risk for GDM. Further studies are needed to replicate these results and to evaluate potential biological mechanisms underlying the observed associations. Keywords: Gestational diabetes mellitus, Persistent organic pollutants, Polychlorinated biphenyls (PCBs), Organochlorine pesticides, Pregnancy

Background: Persistent Organic Pollutants (POPs) are highly-resistant compounds to environmental degradation and due to fat solubility they bioaccumulate through the food chain. As they cross the placenta, in utero exposure to POPs could disrupt child neurodevelopment as they are considered to be neurotoxic. Aims: We examined whether in utero exposure to levels of different POPs is associated with offspring cognitive and behavioral outcomes at 4 years of age in a mother-child cohort in Crete, Greece (Rhea study). Methods: We included 689 mother-child pairs. Concentrations of several polychlorinated biphenyls (PCBs) and other organochlorine compounds (dichlorodiphenyl dichloroethene [DDE], hexachlorobenzene [HCB]) were determined in maternal serum collected in the first trimester of pregnancy by triple quadrupole mass spectrometry. Neurodevelopment at 4 years was assessed by means of the McCarthy Scales of Children's Abilities. Behavioral difficulties were assessed by Strengths and Difficulties Questionnaire and Attention Deficit Hyperactivity Disorder Test. Linear regression analyses were used to estimate the associations between the exposures and outcomes of interest after adjustment for potential confounders. Results: Children with “high” HCB concentrations (≥90th percentile) in maternal serum, demonstrated decreased scores in perceptual performance (adjusted β = −6.07; 95% CI: −10.17, −1.97), general cognitive (adjusted β = −4.97; 95% CI: −8.99, −0.96), executive function (adjusted β = −6.24; 95% CI: −10.36, −2.11) and working memory (adjusted β = −4.71; 95% CI: −9.05, −0.36) scales at 4 years of age. High exposure to PCBs (≥90th percentile) during pregnancy was associated with a 4.62 points reduction in working memory score at 4 years of age (95% CI: −9.10, −0.14). Prenatal exposure to DDE, HCB and PCBs was not associated with child behavioral difficulties. Conclusions: The findings suggest that prenatal exposure to HCB and PCBs may contribute to reduced cognitive development at preschool age. Our results raise the possibility that exposure to HCB may play a more important role in child cognition than previously considered. Keywords: Persistent organic pollutants, PCBs, HCB, Neuropsychological development, Cognition, McCarthy Scales for Children’s Abilities

MeDALL (Mechanisms of the Development of ALLergy; EU FP7-CP-IP; Project No: 261357; 2010-2015) has proposed an innovative approach to develop early indicators for the prediction, diagnosis, prevention and targets for therapy. MeDALL has linked epidemiological, clinical and basic research using a stepwise, large-scale and integrative approach: MeDALL data of precisely phenotyped children followed in 14 birth cohorts spread across Europe were combined with systems biology (omics, IgE measurement using microarrays) and environmental data. Multimorbidity in the same child is more common than expected by chance alone, suggesting that these diseases share causal mechanisms irrespective of IgE sensitization. IgE sensitization should be considered differently in monosensitized and polysensitized individuals. Allergic multimorbidities and IgE polysensitization are often associated with the persistence or severity of allergic diseases. Environmental exposures are relevant for the development of allergy-related diseases. To complement the population-based studies in children, MeDALL included mechanistic experimental animal studies and in vitro studies in humans. The integration of multimorbidities and polysensitization has resulted in a new classification framework of allergic diseases that could help to improve the understanding of genetic and epigenetic mechanisms of allergy as well as to better manage allergic diseases. Ethics and gender were considered. MeDALL has deployed translational activities within the EU agenda.

The evidence regarding a potential link of low-to-moderate iodine deficiency, selenium status, and cadmium exposure during pregnancy with neurodevelopment is either contradicting or limited. We aimed to assess the prenatal impact of cadmium, selenium, and iodine on children's neurodevelopment at 4 years of age. The study included 575 mother-child pairs from the prospective "Rhea" cohort on Crete, Greece. Exposure to cadmium, selenium and iodine was assessed by concentrations in the mother's urine during pregnancy (median 13 weeks), measured by ICPMS. The McCarthy Scales of Children's Abilities was used to assess children's general cognitive score and seven different sub-scales. In multivariable-adjusted regression analysis, elevated urinary cadmium concentrations (≥0.8 µg/L) were inversely associated with children's general cognitive score [mean change: -6.1 points (95 % CI -12; -0.33) per doubling of urinary cadmium; corresponding to ~0.4 SD]. Stratifying by smoking status (p for interaction 0.014), the association was restricted to smokers. Urinary selenium was positively associated with children's general cognitive score [mean change: 2.2 points (95 % CI -0.38; 4.8) per doubling of urinary selenium; ~0.1 SD], although the association was not statistically significant. Urinary iodine (median 172 µg/L) was not associated with children's general cognitive score. In conclusion, elevated cadmium exposure in pregnancy of smoking women was inversely associated with the children's cognitive function at pre-school age. The results indicate that cadmium may adversely affect neurodevelopment at doses commonly found in smokers, or that there is an interaction with other toxicants in tobacco smoke. Additionally, possible residual confounding cannot be ruled out. The “Rhea” project was financially supported by European projects (EU FP6-2003-Food-3-NewGeneris, EU FP6. STREP Hiwate, EU FP7 ENV.2007.1.2.2.2. Project No 211250 Escape, EU FP7-2008-ENV-1.2.1.4 Envirogenomarkers, EU FP7-HEALTH-2009-single stage CHICOS, EU FP7 ENV.2008.1.2.1.6. Proposal No 226285 ENRIECO, EU-FP7-HEALTH-2012 Proposal No 308333 HELIX) and the Greek Ministry of Health (Program of Prevention of obesity and neurodevelopmental disorders in preschool children, in Heraklion district, Crete, Greece: 2011–2014; “Rhea Plus”: Primary Prevention Program of Environmental Risk Factors for Reproductive Health, and Child Health: 2012–2015). The present study was also funded by Karolinska Institutet, the Swedish Research Council Formas (Project No. 210-2013-751), and Swedish Research Council