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Results from previous studies on associations between maternal fish and seafood intakes and fetal growth are inconclusive. The aim of the present study was to investigate how maternal intakes of seafood, subtypes of seafood and supplementary n-3 fatty acids were associated with infant birth weight, length and head circumference in a prospective study in Norway. The study population included 62 099 participants in the Norwegian Mother and Child Cohort Study. The mothers answered an FFQ in mid pregnancy. The FFQ comprised detailed questions about intake of various seafood items and n-3 supplements. Data on infant birth weight, length and head circumference were obtained from the Medical Birth Registry. We used multivariable regression to examine how total seafood, various seafood subtypes and supplementary n-3 intakes were associated with birth size measures. Total seafood intake was positively associated with birth weight and head circumference. Lean fish was positively associated with all birth size measures; shellfish was positively associated with birth weight, while fatty fish was not associated with any birth size measures. Intake of supplementary n-3 was negatively associated with head circumference. The relative risk of giving birth to a small baby ( < 2500 g) in full-term pregnancies was significantly lower in women who consumed >60 g/d of seafood than in women who consumed <= 5 g/d (OR = 0·56 (95 % CI 0·35, 0·88). In conclusion, maternal seafood consumption was positively associated with birth size, driven by lean fish intake, while supplementary n-3 intake was negatively associated with infant head circumference. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to analyze whether maternal negative affectivity assessed in pregnancy is related with subsequent infant food choices.Design: The study design was a cohort study.Subjects: The subjects were mothers (N=37 919) and their infants participating in the Norwegian Mother and Child Cohort Study conducted by the Norwegian Institute of Public Health.Measurements: Maternal negative affectivity assessed prepartum (Hopkins Symptom Checklist 5 (SCL-5) at weeks 17 and 30 of pregnancy), introduction of solid foods by month 3 and feeding of sweet drinks by month 6 (by the reports of the mothers) were analyzed.Results: Mothers with higher negative affectivity were 64% more likely (95% confidence interval 1.5-1.8) to feed sweet drinks by month 6, and 79% more likely (95% confidence interval 1.6-2.0) to introduce solid foods by month 3. These odds decreased to 41 and 30%, respectively, after adjusting for mother's age, body mass index (BMI) and education.Conclusion: The maternal trait of negative affectivity is an independent predictor of infant feeding practices that may be related with childhood weight gain, overweight and obesity. [ABSTRACT FROM AUTHOR]

The aim of this article is to describe the main methodological challenges in the monitoring of dietary intake in the Norwegian Mother and Child Cohort Study (MoBa), a pregnancy cohort aiming to include 100 000 participants. The overall challenge was to record dietary patterns in sufficient detail to support future testing of a broad range of hypotheses, while at the same time limiting the burden on the participants. The main questions to be answered were: which dietary method to choose, when in pregnancy to ask, which time period should the questions cover, which diet questions to include, how to perform a validation study, and how to handle uncertainties in the reporting. Our decisions were as follows: using a semi-quantitative food frequency questionnaire (FFQ) (in use from 1 March 2002), letting the participants answer in mid-pregnancy, and asking the mother what she has eaten since she became pregnant. The questions make it possible to estimate intake of food supplements, antioxidants and environmental contaminants in the future. Misreporting is handled by consistency checks. Reports with a calculated daily energy intake of <4.5 and >20 MJ day−1 are excluded, about 1% in each end of the scale. A validation study confirmed that the included intakes are realistic. The outcome of our methodological choices indicates that our FFQ strikes a reasonable balance between conflicting methodological and scientific interests, and that our approach therefore may be of use to others planning to monitor diet in pregnancy cohorts. [ABSTRACT FROM AUTHOR]

The aim of the present study was to examine the relative validity of foods and nutrients calculated by a new food frequency questionnaire (FFQ) in the Norwegian Mother and Child Cohort Study (MoBa). Reference measures were a 4-day weighed food diary (FD), a motion sensor for measuring total energy expenditure, one 24-h urine collection for analysis of nitrogen and iodine excretion, and a venous blood specimen for analysis of plasma 25-hydroxy-vitamin D and serum folate. A total of 119 women participated in the validation study, and 112 completed the motion sensor registration. Overall, the level of agreement between the FFQ and the FD was satisfactory, and significant correlations were found for all major food groups and for all nutrients except vitamin E. The average correlation coefficient between the FFQ and the FD for daily intake was 0.48 for foods and 0.36 for nutrients, and on average, 68% of the participants were classified into the same or adjacent quintiles by the two methods. Estimated total energy expenditure indicated that under-reporting of energy intake was more extensive with the FD than with the FFQ. The biological markers confirmed that the FFQ was able to distinguish between high and low intakes of nutrients, as measured by vitamin D, folate, protein and iodine. This validation study indicates that the MoBa FFQ produces reasonable valid intake estimates and is a valid tool to rank pregnant women according to low and high intakes of energy, nutrients and foods. [ABSTRACT FROM AUTHOR]

Objective: To validate a new food-frequency questionnaire (FFQ) for measuring the intake of fruit, vegetables and tea reported by women participating in the Norwegian Mother and Child Cohort Study (MoBa).Design: Intake of fruits, vegetables and tea estimated by the FFQ was compared with urinary flavonoid excretion, plasma carotenoid concentration and intake measured by a 4-day weighed food diary (FD). The triangular method was applied to calculate FFQ validity coefficients using two independent biomarkers.Setting and Subjects: One hundred and nineteen women participating in MoBa.Results: The FFQ estimate of fruit intake was significantly correlated with urine phloretin (r = 0.33), citrus fruit/juice with urine hesperetin (r = 0.44), cooked vegetables with plasma alpha-carotene (r = 0.37), and tea with urine kaempferol (r = 0.41) (P < 0.01 for all). On average, 60% of the participants fell into the same or adjacent quintiles when classified by FFQ and biomarkers. Significant correlations between the FFQ and FD were found for fruit (r = 0.39), vegetables (r = 0.34), juices (r = 0.50) and tea (r = 0.53). The FFQ validity coefficient was 0.65 for citrus fruit/juice and 0.59 for cooked vegetables as calculated by the triangular method.Conclusions: The validation study shows that the MoBa FFQ can be used to estimate fruit, juice, vegetable and tea intake in pregnant Norwegian women, and to rank individuals within the distribution. [ABSTRACT FROM AUTHOR]

The 4th edition of the Nordic Nutrition Recommendations, NNR 2004, gives the proportions between energy yielding nutrients, recommended daily intakes (RI) of certain vitamins and minerals, and reference values for energy intakes in different age and sex groups. Recommendations are also given for dietary fibre, salt and alcohol. Recommendations on daily physical activity are now included and interaction with physical activity has been taken into account for the individual nutrient recommendations wherever appropriate. For adults 30 minutes of daily physical activity of at least moderate intensity is recommended. More physical activity (about 60 minutes daily) with a moderate and/or vigorous intensity may be needed for prevention of weight gain. For children a minimum of 60 minutes of physical activity every day is recommended. As in the 3rd edition, the recommendation is to limit of the intake of saturated plus trans fatty acids to about 10% of the total energy intake (E%) and of the total fat intake to 30 E%. The intake of carbohydrate and dietary fibres should increase, while the intake of refined sugars should not exceed 10 E%. The RI for vitamin A (women) has been lowered, while it has been increased for vitamin D (children and adults up to 60 y), vitamin C (adults) and folate (women of reproductive age; pregnant and lactating women). [ABSTRACT FROM AUTHOR]

Objectives: To examine dietary iodine sources and to estimate the dietary iodine intake of the Norwegian population.Design: Food iodine analyses carried out in Norway during the last 10 years were compiled, and iodine intake calculated on the basis of food intake data from nation-wide dietary surveys among children and adults. The food intake of adults was measured by a self-administrated food-frequency questionnaire, which covered habitual diet during the past year. The food intake of children was measured by dietary record during four consecutive days.Setting: Neither household nor industrial iodisation of salt is mandatory in Norway, but some brands of table salt have 5 microg of iodine added per gram of NaCl. In spite of this, the population has been considered iodine-replete for decades, i.e. having an iodine intake well above the Recommended Dietary Allowance of 150 microg day(-1). This assumption has not been substantiated by dietary surveys.Subjects: The adults included 1374 females and 1298 males aged 16-79 years. The children included 185 girls and 206 boys aged 4 years, 411 girls and 404 boys aged 9 years, and 517 girls and 492 boys aged 13 years.Results: The calculated iodine intake was in the range of 100-250 microg day(-1) in the majority of the adult population. The mean iodine intake was 136 microg day(-1) (170 microg I/10 MJ) among women and 176 microg day(-1) (161 microg I/10 MJ) among men. For children the iodine intake was in the range of 100-120 microg day(-1). Milk and dairy products contributed approximately 55% and 70% of the dietary iodine intake in adults and children, respectively. Fish contributed more than 20% of the iodine intake in adults and about 10% in children. The iodine contribution of drinking water was negligible.Conclusions: While fish has the highest natural concentration of iodine and as such is an excellent iodine source, milk and diary products are the main determinants of iodine intake in the Norwegian population. Iodisation of cow fodder has been mandatory in Norway since 1950 and provides an efficient alternative to universal salt iodisation. Our results show that the dietary iodine intake of adults is in the range considered to be sufficient. The dietary intake of iodine was at recommended levels among the youngest children; however, it decreased among adolescents, especially among girls. [ABSTRACT FROM AUTHOR]

Objective: To describe how a risk analysis can be applied to food fortification, with emphasis on voluntary fortification and intake levels that might exceed usual dietary levels.Design: Use of the risk analysis model as a frame to classify nutrients according to the risk of exceeding upper safe intake levels. Furthermore, to apply the model when discussing possible consequences of liberal fortification practices on eating behaviour and disease patterns.Setting: The discussion on food fortification presently going on internationally.Results: Micronutrients can be classified according to their safety margin, i.e. the size of the interval between the recommended intake and the upper safe level of intake. We suggest that nutrients with a small safety margin, i.e. for which the upper safe level is less than five times the recommended intake, be placed in a category A and should be handled with care (retinol, vitamin D, niacin, folate and all minerals). Category B comprises nutrients with an intermediate safety margin (vitamins E, B6, B12 and C), while nutrients that according to present knowledge are harmless even at 100 times the recommendation (vitamin K, thiamin, riboflavin, pantothenic acid and biotin) are categorised as C.Discussion: The risk analysis model is a useful tool when assessing the risk of both too low and excess intakes of single micronutrients, but can also be applied to analyse the consequences of fortification practices on eating behaviour and disease patterns. Liberal fortification regulations may, for example, distort the conception of what is healthy food, and drive consumption towards a more unhealthy diet, contributing to the plague of overweight and concomitant increased risk of degenerative diseases.Conclusion: The impact of fortification practices on the total eating pattern of a population should become an integrated part of the discussions and regulations connected to the issue. [ABSTRACT FROM AUTHOR]

The overall aim of this paper was to provide background knowledge to the Nordic Nutrition Recommendations 2023 Committee for integrating environmental sustainability in a framework for national Food-Based Dietary Guidelines (FBDG) within the Nordics and Baltics. Additionally, this paper aims to give an overview of recent Nordic scientific literature on environmental impact of foods and dietary patterns and of the FBDG of the Nordics. Finally, we suggest methods for developing national sustainable FBDG. Nordic and Baltic studies on sustainability of diets were searched in August 2022 and complemented with additional relevant literature. The studies show that current diets are far from environmentally sustainable, exceeding planetary boundaries for most impact categories; meat and dairy products being the largest contributors to dietary greenhouse gas emissions (GHGEs) and land use. Scenario, modelling, optimisation and intervention studies confirm the potential of shifting towards more plant-based diets to improve overall diet quality in terms of both health and environmental sustainability. Such diets comprised of vegetables, fruits, legumes, potatoes, whole grain and refined cereal products, nuts, seeds and vegetable oils, with animal foods in moderate or limited amounts. The FBDG in the Nordics promotes more plant-based diets than the current average diet but could improve from further integration of environmental sustainability. To form basis for sustainable FBDG dietary modelling at the national level, prioritising health outcomes and nutritional adequacy is essential. Second, integrating environmental sustainability involves estimating the impact of food choices and amounts on GHGE, land and water use, eutrophication and biodiversity loss. Exploring positive and negative implications of fortified foods and supplementation in relation to nutrient intake, health and environmental sustainability may be needed. Implementing dietary transition requires solutions beyond FBDG to ensure affordability, acceptability and ease of adaption., Competing Interests: This study was funded by the Nordic Council of Ministers, and food and health authorities in Nordic countries. They had no role in the design of the paper, interpretation of results or in the writing of the manuscript. The authors state no conflict of interests. Comments from the public hearing were considered, and references checked for scientific relevance before they were taken into account. The authors solely performed and take full responsibility for interpretation of data and preparation of this manuscript., (© 2024 Ellen Trolle et al.)

Introduction: Sustainable diets promote health and wellbeing and have low environmental impact. They should be accessible, affordable, safe, equitable and culturally acceptable. Translating these general principles into Norwegian-specific dietary recommendations is essential, as foods beneficial for health tend to also be environmentally sustainable. Following the dietary recommendations is an important step towards sustainability., Aim: To identify challenges and potential solutions for transitioning towards more sustainable diets in Norway., Methods: We used scientific articles, reports, policy documents, and statistics on Norwegian food production and consumption to discuss a sustainable diet in a Norwegian context., Results and Discussion: There is a large gap between dietary guidelines and actual consumption. More than 60% of the calories in the Norwegian diet are based on imported foods and feed. Changing people's diet is identified as central in transforming the food system to become more sustainable, as is prioritizing the use of local resources. Good animal health and welfare are also fundamental premises for a sustainable food system., Conclusions: Transitioning to a more sustainable diet requires comprehensive efforts at multiple levels. There is considerable room for action to increase the use of Norwegian resources in a sustainable and responsible way. Potential strategies include reducing meat intake in favour of plant-based foods and fish, consuming more local products, decreasing food waste and supporting agricultural practices that promote environmental and social sustainability. A more sustainable diet may also lead to significantly increased self-sufficiency and food security in Norway ., Competing Interests: Declaration of conflicting interestsThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Anne Lise Brantsæter was co-author on the background paper on iodine for Nordic Nutrition Recommendations 2023. Liv Elin Torheim was co-author on the background paper on legumes for Nordic Nutrition Recommendations 2023. Helle Margrete Meltzer was a member of the Nordic Nutrition Recommendations 2023 working group and co-author on three of the background papers on diet and sustainability.

For many decades, food-based dietary guidelines (FBDGs) were only health-oriented. This changed post-2009 when gradually, an increasing number of countries began to include environmental sustainability considerations in their guidelines. International organisations such as the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) have stated that governments should include environmental sustainability in future FBDGs. However, methodologies on how this should be done are lacking. Therefore, through workshops and discussions with experts, we analysed a selection of methodologies and classified them into six groups: (1) health first; (2) additional advice; (3) demonstrating synergies; (4) modelling impact; (5) combining strategies; (6) systems first. We then assessed how innovative each approach was and their potential for transformative impact. Of the 6 approaches investigated, only approaches 5 and 6 could be considered as disruptive innovations and leading to major changes. Adding environmental sustainability into FBDGs is a policy innovation and has become a debate between old and new multi-criteria guidelines for eating. With the addition of environmental sustainability in FBDGS, a new or emerging set of multi-criteria guidelines for judging food are being proposed that challenges past norms and governance. Today, there is growing scientific consensus that diets that are good for human health are also good for the environment. There is also a growing recognition that food system change is inevitable and desirable. We see this as a positive opportunity to collaborate on FBDGs that are more appropriate for the 21st century and ambitious enough to meet the environmental challenges at hand., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Dooren, Loken, Lang, Meltzer, Halevy, Neven, Rubens, Seves-Santman and Trolle.)

Background: Telomere length (TL) and mitochondrial function expressed as mitochondrial DNA copy number (mtDNAcn) are biomarkers of aging and oxidative stress and inflammation, respectively. Methylmercury (MeHg), a common pollutant in fish, induces oxidative stress. We hypothesized that elevated oxidative stress from exposure to MeHg decreases mtDNAcn and shortens TL., Methods: Study participants are 6-11-year-old children from the HELIX multi-center birth cohort study, comprising six European countries. Prenatal and postnatal total mercury (THg) concentrations were measured in blood samples, TL and mtDNAcn were determined in child DNA. Covariates and confounders were obtained by questionnaires. Robust regression models were run, considering sociodemographic and lifestyle covariates, as well as fish consumption. Sex, ethnicity, and fish consumption interaction models were also run., Results: We found longer TL with higher pre- and postnatal THg blood concentrations, even at low-level THg exposure according to the RfD proposed by the US EPA. The prenatal association showed a significant linear relationship with a 3.46 % increase in TL for each unit increased THg. The postnatal association followed an inverted U-shaped marginal non-linear relationship with 1.38 % an increase in TL for each unit increased THg until reaching a cut-point at 0.96 μg/L blood THg, from which TL attrition was observed. Higher pre- and postnatal blood THg concentrations were consistently related to longer TL among cohorts and no modification effect of fish consumption nor children's sex was observed. No association between THg exposure and mtDNAcn was found., Discussion: We found evidence that THg is associated with TL but the associations seem to be time- and concentration-dependent. Further studies are needed to clarify the mechanism behind the telomere changes of THg and related health effects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The terms 'Nordic countries' or 'The Nordics' include the five countries Denmark, Finland, Island, Norway, and Sweden. This review includes evaluation of the Nordic countries against Food and Agricultural Organisation (FAO)/World Health Organizations' (WHO) guiding principles for healthy, sustainable diets with respect to environmental impact (principles #9 - #13) and sociocultural aspects (principles #14 - #16). A food systems perspective is taken to summarize and discuss the most important challenges and opportunities for achieving sustainable diets. Food system, food security, self-sufficiency, and resilience perspectives are applied. The information can underpin decisions when developing and implementing Food Based Dietary Guidelines (FBDG) in the Nordics. None of the Nordic countries are on track to reach the 2030 UN climate and biodiversity goals. We describe how food production, processing, and consumption contribute to these and other environmental challenges, and what kinds of dietary changes/transitions consistent with these goals are required. A major challenge is the high production and consumption of meat and too low consumption of fish, vegetables, and fruits. Meat production is a major source of emissions and, together with farmed fish, heavily dependent on imported feed ingredients, leaving a large land-use and water footprint in exporting countries while domestic land resources are not used optimally. Dietary patterns have changed drastically over the past 50 years, and in large parts of the population, meat consumption has doubled since the 1970s, rendering historic food culture less useful as a basis for present-day recommendations. The Nordics have Europe's lowest use of antibiotics in animal and fish production and have made some progress in reducing food waste along the food chain. A major opportunity is better alignment of food production and consumption based on local or regional production potentials, in conjunction with better and more constructive integration with the global food system while integrating novel technologies to reduce emissions and resource use., Competing Interests: The authors declare no potential conflicts of interest. The authors have not received any funding or benefits from industry or elsewhere to conduct this study., (© 2024 Helle Margrete Meltzer et al.)

Introduction: Cerebral palsy (CP) is the most common motor disability in childhood, but its causes are only partly known. Early-life exposure to toxic metals and inadequate or excess amounts of essential elements can adversely affect brain and nervous system development. However, little is still known about these as perinatal risk factors for CP. This study aims to investigate the associations between second trimester maternal blood levels of toxic metals, essential elements, and mixtures thereof, with CP diagnoses in children., Methods: In a large, population-based prospective birth cohort (The Norwegian Mother, Father, and Child Cohort Study), children with CP diagnoses were identified through The Norwegian Patient Registry and Cerebral Palsy Registry of Norway. One hundred forty-four children with CP and 1,082 controls were included. The relationship between maternal blood concentrations of five toxic metals and six essential elements and CP diagnoses were investigated using mixture approaches: elastic net with stability selection to identify important metals/elements in the mixture in relation to CP; then logistic regressions of the selected metals/elements to estimate odds ratio (OR) of CP and two-way interactions among metals/elements and with child sex and maternal education. Finally, the joint effects of the mixtures on CP diagnoses were estimated using quantile-based g-computation analyses., Results: The essential elements manganese and copper, as well as the toxic metal Hg, were the most important in relation to CP. Elevated maternal levels of copper (OR = 1.40) and manganese (OR = 1.20) were associated with increased risk of CP, while Hg levels were, counterintuitively, inversely related to CP. Metal/element interactions that were associated with CP were observed, and that sex and maternal education influenced the relationships between metals/elements and CP. In the joint mixture approach no significant association between the mixture of metals/elements and CP (OR = 1.00, 95% CI = [0.67, 1.50]) was identified., Conclusion: Using mixture approaches, elevated levels of copper and manganese measured in maternal blood during the second trimester could be related to increased risk of CP in children. The inverse associations between maternal Hg and CP could reflect Hg as a marker of maternal fish intake and thus nutrients beneficial for foetal brain development., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Weyde, Winterton, Surén, Andersen, Vik, Biele, Knutsen, Thomsen, Meltzer, Skogheim, Engel, Aase and Villanger.)

Introduction: Maternal vitamin D status during pregnancy has been suggested to have a role in childhood adiposity development, but results are conflicting. Our aims were to investigate [1] the relationships between maternal 25-hydroxyvitamin D (25OHD) during pregnancy and the child's body mass index (BMI) and risk of overweight at 5 years of age, and [2] maternal pre-pregnancy BMI as effect modifier for these associations., Methods: Data sources included a subsample from the Norwegian Mother, Father and Child Cohort Study (MoBa sub-cohort; N  = 2,744) and the Swedish GraviD cohort study ( N  = 891). Maternal 25OHD was analyzed in gestational week 18 in the MoBa sub-cohort and week 10 in the GraviD cohort. In the MoBa sub-cohort, parents reported their child's documented measures of weight and length or height from the health card at routine check-up. In the GraviD cohort, this information was collected directly from medical records. Childhood overweight (including obesity) was identified using the International Obesity Task Force cut-offs. Linear and logistic regression models were used to investigate the association between maternal 25OHD and child's BMI and risk of overweight at 5 years of age in each cohort separately, and in a pooled dataset., Results: In the pooled analysis, maternal 25OHD <30 nmol/L was associated with lower BMI in children at 5 years of age, but not with risk of overweight. Interaction analysis showed that the association was predominant among children of mothers with pre-pregnancy BMI ≥25 kg/m 2 ., Conclusion: Low maternal vitamin D status, particularly in mothers with overweight or obesity, predicted lower BMI in their five-year-old children. However, there was no evidence of an effect on overweight in these children., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Amberntsson, Bärebring, Winkvist, Lissner, Meltzer, Brantsæter, Papadopoulou and Augustin.)

Background: Norwegian data on vitamin D status among pregnant women indicate a moderate to high prevalence of insufficient vitamin D status (25-hydroxyvitamin D (25OHD) concentrations ≤50  nmol/L). There is a lack of population-based research on vitamin D intake and determinants of 25OHD in pregnant women from northern latitudes. The aims of this study were (1) to evaluate total vitamin D intake from both diet and supplements, (2) to investigate determinants of vitamin D status, and (3) to investigate the predicted response in vitamin D status by total vitamin D intake, in pregnant Norwegian women., Methods: In total, 2,960 pregnant women from The Norwegian Environmental Biobank, a sub-study within The Norwegian Mother, Father and Child Cohort Study (MoBa), were included. Total vitamin D intake was estimated from a food frequency questionnaire in gestational week 22. Concentrations of plasma 25OHD was analyzed by automated chemiluminescent microparticle immunoassay method in gestational week 18. Candidate determinant variables of 25OHD were chosen using stepwise backward selection and investigated using multivariable linear regression. Predicted 25OHD by total vitamin D intake, overall and stratified by season and pre-pregnancy BMI, was explored using restricted cubic splines in an adjusted linear regression., Results: Overall, about 61% of the women had a total vitamin D intake below the recommended intake. The main contributors to total vitamin D intake were vitamin D supplements, fish, and fortified margarine. Higher 25OHD concentrations were associated with (in descending order of the beta estimates) summer season, use of solarium, higher vitamin D intake from supplements, origin from high income country, lower pre-pregnancy BMI, higher age, higher vitamin D intake from foods, no smoking during pregnancy, higher education and energy intake. During October-May, a vitamin D intake according to the recommended intake was predicted to reach sufficient 25OHD concentrations >50  nmoL/L., Conclusion: The findings from this study highlight the importance of the vitamin D intake, as one of few modifiable determinants, to reach sufficient 25OHD concentrations during months when dermal synthesis of vitamin D is absent., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Amberntsson, Bärebring, Winkvist, Lissner, Meltzer, Brantsæter, Papadopoulou and Augustin.)

Background: Maternal thyroid function plays an important role in foetal brain development; however, little consensus exists regarding the relationship between normal variability in thyroid hormones and common neurodevelopmental disorders, such as attention-deficit hyperactivity disorder (ADHD)., Objective: We sought to examine the association between mid-pregnancy maternal thyroid function and risk of clinically diagnosed ADHD in offspring., Methods: We conducted a nested case-control study in the Norwegian Mother, Father and Child Cohort Study. Among children born 2003 or later, we randomly sampled singleton ADHD cases obtained through linkage with the Norwegian Patient Registry (n = 298) and 554 controls. Concentrations of maternal triiodothyronine (T3), thyroxine (T4), T3-Uptake, thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPO-Ab) were measured in maternal plasma, collected at approximately 17 weeks' gestation. Indices of free T4 (FT4i) and free T3 (FT3i) were calculated. We used multivariable adjusted logistic regression to calculate odds ratios and accounted for missing covariate data using multiple imputation. We used restricted cubic splines to assess non-linear trends and provide flexible representations. We examined effect measure modification by dietary iodine and selenium intake. In sensitivity analyses, we excluded women with clinically significant thyroid disorders (n = 73)., Results: High maternal T3 was associated with increased risk of ADHD (5th vs 1st quintile odds ratio  2.27, 95% confidence interval 1.21, 4.26). For FT4i, both the lowest and highest quintiles were associated with an approximate 1.6-fold increase in risk of ADHD, with similar trends found for T4. The FT4i association was modified by dietary iodine intake such that the highest risk strata were confined to the low intake group., Conclusions: Both high and low concentrations of maternal thyroid hormones, although within population reference ranges, increase the risk of ADHD in offspring. Increased susceptibility may be found among women with low dietary intake of iodine and selenium., (© 2022 John Wiley & Sons Ltd.)

Background: A high consumption of ultra-processed foods (UPFs) is often associated with low nutritional quality, but data on associations with biomarkers are scarce. We aimed to explore associations between UPF intake, diet quality, and concentrations of biomarkers of nutrition and inflammation measured in mid-pregnancy., Methods: This cross-sectional study included n = 2,984 pregnant women recruited during 2002-2008 in the Norwegian Mother, Father, and Child Cohort Study (MoBa). Concentrations of C-reactive protein (CRP) and 21 nutritional biomarkers including carotenes (α-carotene, β-carotene, γ-carotene, α-cryptoxanthin, β-cryptoxanthin, lutein, lycopene), vitamins [α-tocopherol, γ-tocopherol, 25-hydroxyvitamin D (25-OH-D), retinol], creatinine, elements (K, Na, Co, Cu, Mn, Mo, Se, Zn), and ferritin (Fe) were measured in blood and urine collected in mid-pregnancy. Habitual diet in pregnancy was assessed using a validated semi-quantitative food frequency questionnaire. We calculated the relative (%) energy contribution of UPF to overall intake according to the NOVA classification. We also applied a diet quality index (DQI) adapted to assess adherence to Norwegian dietary guidelines (DQI; min-max: 0-110, higher score meaning higher adherence). We present summary statistics for biomarker concentrations and explored associations between UPF intake or the DQI and measured biomarkers using adjusted linear, logistic, and generalized additive regression models., Results: Ultra-processed food intake was positively associated with biomarker concentrations of vitamin E (γ-tocopherol), creatinine, K, and Na [βs: 5.6 to 17% increase in biomarker concentration per interquartile range (IQR) increase in UPF intake] and negatively associated with carotenoids (α-carotene, β-carotene, γ-carotene, α-cryptoxanthin, β-cryptoxanthin, lutein, lycopene), vitamin A, Mo, and Se (βs: -2.1 to -18%). Inversely, high diet quality (i.e., the DQI) was positively associated with concentrations of carotenoids, vitamins [vitamin A (retinol) and D (25-OH-D)], and Se (β: 1.5 to 25%) and negatively associated with vitamin E (γ-tocopherol), creatinine, and Na (β: -4.8 to -8.3%). A weak, positive association was found between UPF and CRP (β: 5.4%, 95% CI 0.12-11%)., Conclusion: High UPF intake was associated with reduced concentrations of nutrition biomarkers in mid-pregnancy. Associations in the opposite direction were found with high adherence to the Norwegian dietary guidelines, suggesting that the two dietary scoring systems capture diet quality in a mirrored manner in this population., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kelsey, Papadopoulou, Borge, Dahl, Brantsæter, Erlund, Meltzer, Haug and Caspersen.)

Background: The relationship between iodine intake and depression is unknown. The aim of the present study was to investigate whether iodine intake was associated with symptoms of perinatal emotional distress and depression in a mild- to moderately iodine deficient population., Methods: The study population comprised 67,812 women with 77,927 pregnancies participating in the Norwegian Mother, Father and Child Cohort Study. Self-reported emotional distress and depressive symptoms were reported in pregnancy and at six months postpartum. Iodine intake was assessed by a food frequency questionnaire in mid-pregnancy. Urinary iodine concentration (UIC) was available for 2792 pregnancies., Results: The median iodine intake from food was 121 μg/day and the median UIC was 68 μg/L. The prevalence of high scores for emotional distress was 6.6 % in pregnancy and 5.8 % six months postpartum, and for high scores on postpartum depression it was 10.3 %. In non-users of iodine supplements (63 %), a low maternal iodine intake from food (lower than ~100-150 μg/day) was associated with increased risk of high scores of emotional distress and depression both in pregnancy and six months postpartum (p < 0.001). Iodine supplement use was associated with increased risk of high scores of emotional distress in pregnancy compared to no supplement use or use of supplements without iodine., Limitations: Observational design, self-report information, and short scales to assess symptoms of emotional distress and depression., Conclusion: A low habitual iodine intake was associated with increased prevalence of perinatal emotional distress and depression. The potential non-beneficial effect of iodine supplements may have biological explanations. More studies are needed., Competing Interests: Conflict of Interest M.H.A. was until Dec. 2019 employed by the Norwegian dairy company TINE SA, and she participated in this project as an industrial Ph.D.-student financed partly by TINE SA and partly by The Research Council of Norway. This project is designed, owned, and administered by The Norwegian Institute of Public Health (NIPH) and analysis of the data follow from protocol. All results of analysis in the project are to be published regardless of the results. TINE SA supported the project to raise awareness on the importance of iodine and to gain more knowledge about the potential health effects of milk in the Norwegian diet. Today, M.H.A. is a full-time researcher at the NIPH. The other authors declare that they have no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objective: While maternal fish consumption in pregnancy has consistently been linked to better cognitive and emotional outcomes in children, fish is also a primary source of exposure to methyl mercury (MeHg), which has been linked to poorer child cognitive outcomes. The aim of this study was to evaluate the associations between MeHg exposure, using calculated MeHg exposure from maternal diet and total mercury (Hg) concentration in maternal blood during pregnancy, and child internalising and externalising behaviours at 3 and 5 years of age., Design and Participants: The study sample comprised 51 238 mother-child pairs in the Norwegian Mother, Father and Child Cohort Study. Data on maternal blood Hg concentration in gestational week 18 were available for a sub-sample of 2936 women. Maternal MeHg exposure from diet was calculated from a validated Food Frequency Questionnaire answered in mid-pregnancy. Mothers reported children's emotional behaviour at age 3 and 5 years by questionnaires including twenty items from the Child Behaviour Checklist. Longitudinal associations were examined using generalised estimating equations, adjusted for potential confounders and stratified by maternal fish intake., Results: Maternal blood Hg concentration (median=1.02 µg/L, 90th percentile=2.22, range=0-13.8) was not associated with emotional behaviour in children. Increasing dietary MeHg intake (median 0.15 µg/kg body weight/week, 90th percentiles=0.31, range=0-1.86) was significantly associated with lower internalising β=-0.03 (95% CI -0.05 to -0.00) and externalising child behaviours β=-0.04 (95% CI -0.07 to -0.02) in adjusted models. The inverse associations were also apparent when stratifying by low/high maternal fish intake (<400 and ≥400 g/week)., Conclusions: The results indicated that prenatal MeHg exposure, well below the weekly tolerable intake established by European Food Safety Authority (1.3 µg/kg bw), did not adversely affect child emotional regulation. Children of mothers consuming fish regularly were less likely to show signs of emotional behavioural problems., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Competing Interests: Declaration of competing interest Authors don't have any conflict of interest.

Background: Maternal diabetes is a well-known risk factor for pregnancy complications. Possible links between long-term maternal blood sugar in the normal range and pregnancy complications are less well described., Methods: We assayed glycated haemoglobin (HbA1c) in blood samples collected around the 18th week of pregnancy for 2937 singleton pregnancies in the Norwegian Mother, Father and Child Cohort Study (2000-09). Perinatal outcomes (gestational length, birthweight, birth length and head circumference, large-for-gestational age, small-for-gestational age, congenital malformations, preterm delivery and preeclampsia) were obtained from medical records. We tested associations using linear and log-binomial regression, adjusting for maternal age, body mass index (BMI) and smoking., Results: Size at birth increased modestly but linearly with HbA1c. Birthweight rose 0.10 standard deviations [95% confidence interval (CI): 0.03, 0.16], for each 5-mmol/mol unit increase in HbA1c, corresponding to about 40 g at 40 weeks of gestation. Large-for-gestational age rose 23% (95% CI: 1%, 50%) per five-unit increase. Other pregnancy complications increased in non-linear fashion, with strongest associations within the top quartile of HbA1c (>35 mmol/mol or >5.4%). Per unit HbA1c within the top quartile, preterm delivery increased by 14% (95% CI: 1%, 31%), preeclampsia increased by 20% (95% CI: 5%, 37%) and gestational duration decreased by 0.7 days (95% CI: -1.0, -0.3)., Conclusions: Among women with no recorded diabetes, higher HbA1c levels at 18 gestational weeks were associated with important perinatal outcomes independent of mother's age, smoking or BMI., (© The Author(s) 2022. Published by Oxford University Press on behalf of the International Epidemiological Association.)

Record linkage of human biomonitoring (HBM) survey data with administrative register data can be used to enhance available datasets and complement the possible shortcomings of both data sources. Through record linkage, valuable information on medical history (diagnosed diseases, medication use, etc.) and follow-up information on health and vital status for established cohorts can be obtained. In this study, we investigated the availability of health registers in different EU Member States and EEA countries and assessed whether they could be linked to HBM studies. We found that the availability of administrative health registers varied substantially between European countries as well as the availability of unique personal identifiers that would facilitate record linkage. General protocols for record linkage were similar in all countries with ethical and data protections approval, informed consent, approval by administrative register owner, and linkage conducted by the register owner. Record linkage enabled cross-sectional survey data to be used as cohort study data with available follow-up and health endpoints. This can be used for extensive exposure-health effect association analysis. Our study showed that this is possible for many, but not all European countries.

Background: Early childhood growth can affect the child's health status later in life. Maternal vitamin D status has been suggested to affect early childhood growth. However, there is a lack of studies investigating the role of maternal vitamin D status on growth trajectories during infancy. By using growth mixture modeling (GMM), maternal vitamin D status during pregnancy can be investigated in relation to different classes of infant growth trajectories., Objectives: To examine the association between maternal 25-hydroxyvitamin D (25OHD) and classes of infant body mass index (BMI) growth trajectories., Methods: Mother-child pairs were included from the Norwegian Mother, Father, and Child Cohort Study (MoBa, n = 2522) and the Swedish GraviD cohort ( n  = 862). Maternal 25OHD in pregnancy was analyzed by liquid chromatography tandem mass spectrometry. Children's weights and heights were registry-based. GMM identified classes of infant BMI growth trajectories up to 2 years. The association between maternal 25OHD and infant BMI class by cohort was estimated using a log-link generalized linear model. Mixed model analysis estimated the pooled association including both cohorts., Results: Two infant BMI classes were identified, stable normal and stable high. In MoBa, maternal 25OHD <50 and 50-75 nmol/L were associated (RR 2.70, 95% CI 1.26-5.77 and RR 2.56, 95% CI 1.20-5.47) with a higher risk of the infant stable high BMI class, compared with 25OHD >75 nmol/L. In GraviD, no association was found. In pooled analysis, maternal 25OHD ≤75 nmol/L was non-significantly associated with a higher risk of the stable high BMI growth class., Conclusions: Maternal 25OHD ≤75 nmol/L may be associated with a higher class of BMI growth trajectory during infancy., Competing Interests: The authors declare no conflict of interest., (© 2022 The Authors. Obesity Science & Practice published by World Obesity and The Obesity Society and John Wiley & Sons Ltd.)

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 1 H NMR spectroscopy in a multicountry 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 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., Competing Interests: NS, AS, EP, AN, YZ, KM, CL, LM, SF, LA, SA, XB, AB, MC, SF, RG, BH, RM, HM, CM, FR, OR, TR, EB, ES, JU, MV, PV, TV, JW, DC, MV, HK, LC No competing interests declared, MC Is an employee of AstraZeneca. The author declares that no other competing interests exist, (© 2022, Stratakis et al.)

Background/objectives: Poor diet quality in early life can have long-term health effects, but the evidence is largely from cross-sectional studies. Our objective was to examine diet quality of Norwegian children by applying a-priori diet quality indices, identify early life determinants and examine prospective associations with overweight., Subjects/methods: We included 34,074 preschoolers (3-year-olds) and 18,350 school-aged children (7-years-olds) from the prospective, population-based Norwegian Mother, Father and Child Cohort Study. Diet quality was assessed as (i) adherence to a Mediterranean diet, estimated by the food frequency-based Mediterranean Diet Score (fMDS, score range: 0-6) and (ii) by the diet quality index (DQI, score range: -33% to 100%), reflecting compliance to food-based dietary guidelines. In multivariate analyses we explored perinatal and childhood characteristics as potential determinants of diet quality. We used logistic regression to examine the associations between diet quality at 3 years and BMI status at 8 years, adjusting for relevant confounders and diet quality at 7 years., Results: One in three children had high MD adherence at 3 and 8 years, and DQI (mean 60%) at 3 and 7 years was strongly correlated (r = 0.48, p < 0.001). Short breastfeeding duration, physical activity and sleep duration and long screentime at 18 months were associated with 2-3% lower DQI at 3 years. At both ages, maternal diet quality was the strongest prospective predictor of DQI (beta = 5%, 95% CI = 4.7, 5.2 and beta = 3.1%, 95% CI = 2.8, 3.4), and screentime was the strongest cross-sectional predictor (beta = -5.2%, 95% CI = -5.9, -4.5 and beta = -4.1%, 95% CI = -5.0, -3.2). High DQI score at 3 years, but not MD adherence, was associated with a lower risk for overweight (including obesity) at 8 years, compared to low DQI (lower tertile) (adjusted OR = 0.77, 95% CI = 0.62, 0.96)., Conclusions: Our study provides evidences that high diet quality in early childhood may reduce the risk for overweight in later childhood, independent of the current dietary behaviors., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Pregnancy-induced hypertensive disorders (PIHD), including preeclampsia, cause maternal and perinatal morbidity and mortality worldwide. Several studies have linked selenium supplementation and selenium status to the risk of preeclampsia, but there are no published prospective population-based studies examining associations between dietary selenium intake and preeclampsia., Aim: To examine associations between selenium intake from diet and supplements and selenium blood status and PIHD incidence, with sub-analyses for pregnancy-induced hypertension (PIH) and preeclampsia, in a large pregnancy cohort., Method: The study is based on 69,972 singleton pregnancies from the Norwegian Mother, Father and Child Cohort Study. Maternal dietary selenium intake was assessed with a validated, semi-quantitative food frequency questionnaire at about gestational week 22. Maternal selenium concentrations were measured in whole blood collected around gestational week 18 in a subset of 2572 women. Preeclampsia and PIH diagnosges were obtained from the Medical Birth Registry of Norway., Results: Participants had a median dietary selenium intake of 53 μg/day (IQR 44-62). Dietary selenium intake was not significantly associated with PIHD (adjusted (a) OR 1.03, 95% CI 0.98, 1.08 per SD of selenium intake), preeclampsia or PIH. Threshold analyses for deciles of dietary selenium intake did not show any significant associations. Neither inorganic (aOR 1.01, 95% CI 0.98, 1.05) or organic selenium supplement intake (aOR 0.98, 95% CI 0.95, 1.02) or selenium blood status was significantly associated with PIHD (aOR 1.03, 95% CI 0.86, 1.22) or PIHD subgroups., Conclusion: No significant associations were found between reported selenium intake from diet, or dietary supplements or whole-blood selenium status and PIHD in general or preeclampsia specifically. Hence, the results of this large population-based study, with selenium intake close to the recommended daily intake, do not support previous findings indicating a possible protective effect of selenium supplementation or selenium status with regard to preeclampsia incidence., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Adequate iron supply in pregnancy is important for both the woman and the fetus, but iron status is often assessed late in first trimester, if assessed at all. Therefore, identification of factors associated with iron status is important to target vulnerable groups with increased risk of deficiency. Our objectives were to (1) describe iron status in mid-pregnancy and (2) identify sociodemographic and lifestyle predictors of pregnancy iron status. This cross-sectional study uses data from The Norwegian Mother, Father and Child Cohort Study (collected 2002-2008) and The Medical Birth Registry of Norway. Iron status was measured as non-fasting plasma ferritin (P-Fe) and transferrin in gestational week (GW) 18 (n 2990), and by lowest reported Hb in GW 0-30 (n 39 322). We explored predictors of iron status with elastic net, linear and log-binomial regression models. Median P-Fe was 33 μg/l, and 14 % had depleted iron stores (P-Fe <15 μg/l). P-Fe below 30 μg/l was associated with reduced Hb. We identified eleven predictors, with interpregnancy interval (IPI) and parity among the most important. Depleted iron stores was more common among women with IPI < 6 months (56 %) and 6-11 months (33 %) than among those with IPI 24-59 months (19 %) and among nulliparous women (5 %). Positively associated factors with iron status included hormonal contraceptives, age, BMI, smoking, meat consumption and multi-supplement use. Our results highlight the importance of ferritin measurements in women of childbearing age, especially among women not using hormonal contraceptives and women with previous and recent childbirths.

Background: As part of the process of updating national dietary reference values (DRVs) and food-based dietary guidelines (FBDGs), the Nordic Nutrition Recommendations 2022 project (NNR2022) will select a limited number of topics for systematic reviews (SRs)., Objective: To develop and transparently describe the results of a procedure for prioritisation of topics that may be submitted for SRs in the NNR2022 project., Design: In an open call, scientists, health professionals, national food and health authorities, food manufacturers, other stakeholders and the general population in the Nordic and Baltic countries were invited to suggest SR topics. The NNR2022 Committee developed scoping reviews (ScRs) for 51 nutrients and food groups aimed at identifying potential SR topics. These ScRs included the relevant nominations from the open call. SR topics were categorised, ranked and prioritised by the NNR2022 Committee in a modified Delphi process. Existing qualified SRs were identified to omit duplication., Results: A total of 45 nominations with suggestion for more than 200 exposure-outcome pairs were received in the public call. A number of additional topics were identified in ScRs. In order to omit duplication with recently qualified SRs, we defined criteria and identified 76 qualified SRs. The NNR2022 Committee subsequently shortlisted 52 PI/ECOTSS statements, none of which overlapped with the qualified SRs. The PI/ECOTSS statements were then graded 'High' ( n = 21), 'Medium' ( n = 9) or 'Low' ( n = 22) importance, and the PI/ECOTSS statements with 'High' were ranked in a Delphi process. The nine top prioritised PI/ECOTSS included the following exposure-outcome pairs: 1) plant protein intake in children and body growth, 2) pulses/legumes intake, and cardiovascular disease and type 2 diabetes, 3) plant protein intake in adults, and atherosclerotic/cardiovascular disease and type 2 diabetes, 4) fat quality and mental health, 5) vitamin B 12 and vitamin B 12 status, 6) intake of white meat (no consumption vs. high consumption and white meat replaced with red meat), and all-cause mortality, type 2 diabetes and risk factors, 7) intake of n-3 LPUFAs from supplements during pregnancy, and asthma and allergies in the offspring, 8) nuts intake and cardiovascular disease (CVD) and type 2 diabetes in adults, 9) dietary fibre intake (high vs. low) in children and bowel function., Discussion: The selection of topics for de novo SRs is central in the NNR2022 project, as the results of these SRs may cause adjustment of existing DRVs and FBDGs. That is why we have developed this extensive process for the prioritisation of SR topics. For transparency, the results of the process are reported in this publication., Conclusion: The principles and methodologies developed in the NNR2022 project may serve as a framework for national health authorities or organisations when developing national DRVs and FBDGs. This collaboration between the food and health authorities in Denmark, Estonia, Finland, Iceland, Latvia, Lithuania, Norway and Sweden represents an international effort for harmonisation and sharing of resources and competence when developing national DRVs and FBDGs., Competing Interests: See sections on ‘Conflict of interest’ and ‘Sponsors of the NNR2022 project’ in the main text of the article by Christensen et al. (4)., (© 2021 Anne Høyer et al.)

Objectives: To examine the associations between maternal vitamin D intake and childhood growth and risk of overweight up to 8 years. We further examined the effect modification by maternal prepregnancy body mass index (BMI)., Design: Prospective population-based pregnancy cohort study., Setting: The Norwegian Mother, Father and Child Cohort Study., Participants: In total, 58 724 mothers and 66 840 singleton children, with information on maternal vitamin D intake during the pregnancy and minimum one postnatal anthropometric measurement., Outcome Measures: Predicted weight and height growth trajectories and velocities from 1 month to 8 years, rapid growth during infancy and toddlerhood, and risk of overweight in preschool and school age., Results: Overall, maternal vitamin D intake was associated with lower weight trajectory, lower odds of rapid weight growth and higher odds of childhood overweight. In children of mothers with prepregnancy normal weight, maternal vitamin D intake was negatively associated with weight trajectory and lower OR of a rapid weight growth during the first year, compared with reference (<5 µg/day). Children of mothers with normal weight, with maternal vitamin D intakes of 10-15 and >15 µg/day, also had 0.86 (95% CI 0.77 to 0.97) and 0.88 (95% CI 0.79 to 0.99) lower odds for overweight at 3 years, compared with reference. In contrast, in children of mothers with prepregnancy overweight (BMI ≥25 kg/m 2 ), vitamin D intake was positively associated with weight trajectory. Children of mothers with overweight, with maternal vitamin D intake of 5-9.9 µg/day, also had (1.09 (95% CI 1.01 to 1.18) and 1.12 (95% CI 1.02 to 1.23)) higher odds for overweight at 5 years and 8 years, compared with reference., Conclusions: Maternal vitamin D intake affects postnatal growth and is inversely associated with childhood overweight in children of mothers with normal weight. Associations between maternal vitamin D intake and child growth and risk of overweight varied by prepregnancy BMI., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.)

Background: Pregnant women and their fetuses are exposed to multiple toxic metals that together with variations in essential element levels may alter epigenetic regulation, such as DNA methylation., Objectives: The aim of the study was to investigate the associations between gestational levels of toxic metals and essential elements and mixtures thereof, with global DNA methylation levels in pregnant women and their newborn children., Methods: Using 631 mother-child pairs from a prospective birth cohort (The Norwegian Mother, Father and Child Cohort Study), we measured maternal blood concentration (gestation week ~18) of five toxic metals and seven essential elements. We investigated associations as individual exposures and two-way interactions, using elastic net regression, and total mixture, using quantile g-computation, with blood levels of 5-methylcytocine (5mC) and 5-hydroxymethylcytosine (5hmC) in mothers during pregnancy and their newborn children (cord blood). Multiple testing was adjusted for using the Benjamini and Hochberg false discovery rate (FDR) approach., Results: The most sensitive marker of DNA methylation appeared to be 5mC levels. In pregnant mothers, elastic net regression indicated associations between 5mC and selenium and lead (non-linear), while in newborns results indicated relationships between maternal selenium, cobalt (non-linear) and mercury and 5mC, as well as copper (non-linear) and 5hmC levels. Several possible two-way interactions were identified (e.g. arsenic and mercury, and selenium and maternal smoking in newborns). None of these findings met the FDR threshold for multiple testing. No net effect was observed in the joint (mixture) exposure-approach using quantile g-computation., Conclusion: We identified few associations between gestational levels of several toxic metals and essential elements and global DNA methylation in pregnant mothers and their newborn children. As DNA methylation dysregulation might be a key mechanism in disease development and thus of high importance for public health, our results should be considered as important candidates to investigate in future studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Background and Aims: Nonalcoholic fatty liver disease (NAFLD) is the most prevalent cause of liver disease in children. Mercury (Hg), a ubiquitous toxic metal, has been proposed as an environmental factor contributing to toxicant-associated fatty liver disease., Approach and Results: We investigated the effect of prenatal exposure to Hg on childhood liver injury by combining epidemiological results from a multicenter mother-child cohort with complementary in vitro experiments on monocyte cells that are known to play a key role in liver immune homeostasis and NAFLD. We used data from 872 mothers and their children (median age, 8.1 years; interquartile range [IQR], 6.5-8.7) from the European Human Early-Life Exposome cohort. We measured Hg concentration in maternal blood during pregnancy (median, 2.0 μg/L; IQR, 1.1-3.6). We also assessed serum levels of alanine aminotransferase (ALT), a common screening tool for pediatric NAFLD, and plasma concentrations of inflammation-related cytokines in children. We found that prenatal Hg exposure was associated with a phenotype in children that was characterized by elevated ALT (≥22.1 U/L for females and ≥25.8 U/L for males) and increased concentrations of circulating IL-1β, IL-6, IL-8, and TNF-α. Consistently, inflammatory monocytes exposed in vitro to a physiologically relevant dose of Hg demonstrated significant up-regulation of genes encoding these four cytokines and increased concentrations of IL-8 and TNF-α in the supernatants., Conclusions: These findings suggest that developmental exposure to Hg can contribute to inflammation and increased NAFLD risk in early life., (© 2021 by the American Association for the Study of Liver Diseases.)

Background: Maternal seafood intake during pregnancy and prenatal mercury exposure may influence children's growth trajectories., Methods: This study, based on the Norwegian Mother, Father and Child Cohort Study (MoBa), includes 51 952 mother-child pairs recruited in pregnancy during 2002-08 and a subsample (n = 2277) with maternal mercury concentrations in whole blood. Individual growth trajectories were computed by modelling based on child's reported weight and length/height from 1 month to 8 years. We used linear mixed-effects regression analysis and also conducted discordant-sibling analysis., Results: Maternal lean fish was the main contributor to total seafood intake in pregnancy and was positively but weakly associated with child body mass index (BMI) growth trajectory. Higher prenatal mercury exposure (top decile) was associated with a reduction in child's weight growth trajectory, with the estimates ranging from -130 g [95% Confidence Intervals (CI) = -247, -12 g] at 18 months to -608 g (95% CI = -1.102, -113 g) at 8 years. Maternal fatty fish consumption was positively associated with child weight and BMI growth trajectory, but only in the higher mercury-exposed children (P-interaction = 0.045). Other seafood consumption during pregnancy was negatively associated with child weight growth compared with no intake, and this association was stronger for higher mercury-exposed children (P-interaction = 0.004). No association was observed between discordant maternal seafood intake and child growth in the sibling analysis., Conclusions: Within a population with moderate seafood consumption and low mercury exposure, we found that maternal seafood consumption in pregnancy was associated with child growth trajectories, and the direction of the association varied by seafood type and level of prenatal mercury exposure. Prenatal mercury exposure was negatively associated with child growth. Our findings on maternal seafood intake are likely non-causal., (© The Author(s) 2021. Published by Oxford University Press on behalf of the International Epidemiological Association.)

Properly working antioxidant defence systems are important for fetal development. One of the nutrients with antioxidant activity is selenium. Increased maternal selenium intake has been associated with reduced risk for being small for gestational age and preterm delivery. Based on the Norwegian Mother, Father, and Child Cohort Study and the Medical Birth Registry of Norway, we investigated the association of maternal selenium intake from food and dietary supplements during the first half of pregnancy ( n = 71,728 women) and selenium status in mid-pregnancy ( n = 2628 women) with neonatal health, measured as two composite variables (neonatal morbidity/mortality and neonatal intervention). Low maternal dietary selenium intake (<30 µg/day) was associated with increased risk for neonatal morbidity/mortality (adjusted odds ratio (adjOR) 1.36, 95% confidence interval (95% CI) 1.08-1.69) and neonatal intervention (adjOR 1.16, 95% CI 1.01-1.34). Using continuous variables, there were no associations between maternal selenium intake (from diet or supplements) or whole-blood selenium concentration and neonatal outcome in the adjusted models. Our findings suggest that sufficient maternal dietary selenium intake is associated with neonatal outcome. Adhering to the dietary recommendations may help ensure an adequate supply of selenium for a healthy pregnancy and optimal fetal development.

Background: Attention Deficit Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental disorder. Effective long-term treatment options are limited, which warrants increased focus on potential modifiable risk factors. The aim of this study was to investigate associations between maternal diet quality during pregnancy and child diet quality and child ADHD symptoms and ADHD diagnosis., Methods: This study is based on the Norwegian Mother, Father and Child Cohort Study (MoBa). We assessed maternal diet quality with the Prenatal Diet Quality Index (PDQI) and Ultra-Processed Food Index (UPFI) around mid-gestation, and child diet quality using the Diet Quality Index (CDQI) at 3 years. ADHD symptoms were assessed at child age 8 years using the Parent Rating Scale for Disruptive Behaviour Disorders. ADHD diagnoses were retrieved from the Norwegian Patient Registry., Results: In total, 77,768 mother-child pairs were eligible for studying ADHD diagnoses and 37,787 for ADHD symptoms. Means (SD) for the PDQI, UPFI and CDQI were 83.1 (9.3), 31.8 (9.7) and 60.3 (10.6), respectively. Mean (SD) ADHD symptom score was 8.4 (7.1) and ADHD diagnosis prevalence was 2.9% (male to female ratio 2.6:1). For one SD increase in maternal diet index scores, we saw a change in mean (percent) ADHD symptom score of - 0.28 (- 3.3%) (CI: - 0.41, - 0.14 (- 4.8, - 1.6%)) for PDQI scores and 0.25 (+ 3.0%) (CI: 0.13, 0.38 (1.5, 4.5%)) for UPFI scores. A one SD increase in PDQI score was associated with a relative risk of ADHD diagnosis of 0.87 (CI: 0.79, 0.97). We found no reliable associations with either outcomes for the CDQI, and no reliable change in risk of ADHD diagnosis for the UPFI., Conclusions: We provide evidence that overall maternal diet quality during pregnancy is associated with a small decrease in ADHD symptom score at 8 years and lower risk for ADHD diagnosis, with more robust findings for the latter outcome. Consumption of ultra-processed foods was only associated with increased ADHD symptom score of similar magnitude as for overall maternal diet quality, and we found no associations between child diet quality and either outcome. No causal inferences should be made based on these results, due to potential unmeasured confounding.

Background: A previous randomized dietary intervention in pregnant women from the 1970s, the Harlem Trial, reported retarded fetal growth and excesses of very early preterm births and neonatal deaths among those receiving high-protein supplementation. Due to ethical challenges, these findings have not been addressed in intervention settings. Exploring these findings in an observational setting requires large statistical power due to the low prevalence of these outcomes. The aim of this study was to investigate if the findings on high protein intake could be replicated in an observational setting by combining data from two large birth cohorts., Methods: Individual participant data on singleton pregnancies from the Danish National Birth Cohort (DNBC) ( n = 60,141) and the Norwegian Mother, Father and Child Cohort Study (MoBa) ( n = 66,302) were merged after a thorough harmonization process. Diet was recorded in mid-pregnancy and information on birth outcomes was extracted from national birth registries., Results: The prevalence of preterm delivery, low birth weight and fetal and neonatal deaths was 4.77%, 2.93%, 0.28% and 0.17%, respectively. Mean protein intake (standard deviation) was 89 g/day (23). Overall high protein intake (>100 g/day) was neither associated with low birth weight nor fetal or neonatal death. Mean birth weight was essentially unchanged at high protein intakes. A modest increased risk of preterm delivery [odds ratio (OR): 1.10 (95% confidence interval (CI): 1.01, 1.19)] was observed for high (>100 g/day) compared to moderate protein intake (80-90 g/day). This estimate was driven by late preterm deliveries (weeks 34 to <37) and greater risk was not observed at more extreme intakes. Very low (<60 g/day) compared to moderate protein intake was associated with higher risk of having low-birth weight infants [OR: 1.59 (95%CI: 1.25, 2.03)]., Conclusions: High protein intake was weakly associated with preterm delivery. Contrary to the results from the Harlem Trial, no indications of deleterious effects on fetal growth or perinatal mortality were observed.

Selenium is an essential trace element involved in the body's redox reactions. Low selenium intake during pregnancy has been associated with low birth weight and an increased risk of children being born small for gestational age (SGA). Based on data from the Norwegian Mother, Father and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN), we studied the association of maternal selenium intake from diet and supplements during the first half of pregnancy ( n = 71,728 women) and selenium status in mid-pregnancy ( n = 2628 women) with birth weight and SGA status, according to population-based, ultrasound-based and customized growth standards. An increase of one standard deviation of maternal dietary selenium intake was associated with increased birth weight z-scores ( ß = 0.027, 95% CI: 0.007, 0.041) and lower SGA risk (OR = 0.91, 95% CI 0.86, 0.97) after adjusting for confounders. Maternal organic and inorganic selenium intake from supplements as well as whole blood selenium concentration were not associated with birth weight or SGA. Our results suggest that a maternal diet rich in selenium during pregnancy may be beneficial for foetal growth. However, the effect estimates were small and further studies are needed to elucidate the potential impact of selenium on foetal growth.