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Objectives: To investigate how body height and trajectories of height from infancy through childhood and adolescence were associated with spinal pain in pre- and late adolescence. Methods: This prospective study included 43,765 individuals born into The Danish National Birth Cohort (DNBC) from 1996 to 2003. DNBC-data were linked with health and social data identified from Statistics Denmark registers. Spinal pain was self-reported in both the 11-year- and 18-year follow-up of DNBC and classified according to severity. Body height was measured from birth and onwards and further modelled as distinct developmental height trajectories by using latent growth curve modelling. Associations were estimated by using multinomial logistic regression models. Results: Taller body height in childhood and adolescence was associated with approximately 20% increased likelihood of spinal pain in pre- and late adolescence among girls compared to their peers in the normal height group. For boys, taller body height was associated with spinal pain by late adolescence only. Spinal pain in pre-adolescence almost doubled the likelihood of spinal pain in late adolescence regardless of body height at age 18. Height trajectories confirmed the relationship for girls with the tall individuals being most likely to have spinal pain in both pre- and late adolescence. Conclusion: Tall body height during childhood and adolescence predisposes to spinal pain among girls in both pre-and late adolescence, and among boys in late adolescence. Body height is a contributing factor to the pathogenesis of spinal pain in adolescence; however, the mechanisms may be related to growth velocity, but for now uncertain. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ambient air pollution exposure has been associated with childhood asthma, but previous studies have primarily focused on prevalence of asthma and asthma-related outcomes and urban traffic-related exposures. OBJECTIVE: We examined nationwide associations between pre- and postnatal exposure to ambient air pollution components and asthma incidence in children age 0–19 y. METHODS: Asthma incidence was identified from hospital admission, emergency room, and outpatient contacts among all live-born singletons born in Denmark between 1998 and 2016. We linked registry data with monthly mean concentrations of particulate matter (PM) with aerodynamic diameter ≤2.5 μm (PM2.5) and PM with aerodynamic diameter ≤10 μm (PM10), nitrogen dioxide (NO2), nitrogen oxides, elemental carbon, and organic carbon (OC), sulfur dioxide, ozone, sulfate, nitrate, ammonium, secondary organic aerosols, and sea salt. Associations were estimated with Cox proportional hazard models using fixed prenatal exposure means and time-varying postnatal exposures. RESULTS: Of the 1,060,154 children included, 6.1% had asthma during the mean follow-up period of 8.8 y. The risk of asthma increased with increasing prenatal exposure to all pollutants except for O3 and sea salt. We also observed increased risk after restriction to asthma after age 4 y, after additional adjustment for area-specific socioeconomic status, and for postnatal exposure to most pollutants. The hazard ratio (HR) associated with an interquartile range increase of 2.4 and 8.7 µg/m³ in prenatal exposure was 1.06 [95% confidence interval (CI): 1.04, 1.08] for PM2.5 and 1.04 (95% CI: 1.02, 1.05) for NO2, respectively. This association with PM2.5 was stable after adjustment for NO2, whereas it attenuated for NO2 to 1.01 (95% CI: 0.99, 1.03) after adjustment for PM2.5. For a 0.5-µg/m³ increase in prenatal OC exposure, for which biomass is an important source, the HR was 1.08 (95% CI: 1.06, 1.10), irrespective of adjustment for PM2.5. DISCUSSION: These findings suggest that early-life exposure to ambient air pollution from multiple sources contributes to asthma development. [ABSTRACT FROM AUTHOR]

Context: It remains unclear if migrants have different odds for adverse outcomes associated with gestational diabetes mellitus (GDM).Objective: We investigated if the associations between GDM and adverse pregnancy outcomes are modified by country of origin and examined the odds of these outcomes according to GDM status and country of origin.Methods: Data were extracted from a nationwide register-based study of singleton deliveries in Denmark, 2004-2015. We used logistic regression models and tested for interaction.Results: Among the 710 413 singleton deliveries, 2.6% had GDM and 14.4% were immigrants. Country of origin modified the association between GDM and pre-eclampsia, large for gestational age (LGA), and small for gestational age (SGA) but not between GDM and planned or emergency cesarean section and preterm delivery. GDM increased the risk of pre-eclampsia among women from Denmark (OR 1.28; 95% CI, 1.18-1.39), Lebanon (OR 3.34; 95% CI, 1.35-8.26), and Morocco (OR 2.28; 95% CI, 1.16-6.88). GDM was associated with increased odds of LGA among women from most countries, particularly women from Sri Lanka (OR 4.20; 95% CI, 2.67-6.61), and was associated with reduced odds of SGA in some countries. Compared with Danish-born women with GDM, the odds of LGA were significantly lower and the odds of SGA higher among women with GDM from India, Lebanon, Pakistan, Iraq, and Somalia.Conclusions: Our study documents that different immigrant groups have higher odds of different GDM-associated adverse pregnancy outcomes and also among countries of origin often grouped together. This highlights the importance of increased awareness to both immigrant background and GDM status in the clinical assessment. [ABSTRACT FROM AUTHOR]

Objective: To examine how childhood weight trajectories are associated with disordered eating behaviours (DEBs) in early adolescence. Methods: Self‐reports on DEBs (fasting, purging, and binge eating) were obtained from 18,337 children in the 11‐year follow‐up of the Danish National Birth Cohort. For this population, birth register information on gestational age and birth weight was categorized into the following: small, appropriate, and large for gestational age. Prospective parent‐reported height and weight data at child ages 1 and 7 years were dichotomized using standardized cut‐offs into non‐overweight and overweight. A 12‐category weight trajectory variable was created, and the associations between weight trajectory and DEBs were estimated using logistic regression. Results: In total, 7.0% 11‐ to 12‐year olds reported DEBs. Compared with children born appropriate for gestational age and being non‐overweight at age 1 and 7 years, children born small for gestational age and who were overweight at age 1 and 7 years had a very high risk of disordered eating (OR 7.00; CI [2.57, 19.40]). The statistical analyses revealed, however, that overweight at age 7 years was the main contributor and independently of trajectory increased the risk of disordered eating at age 11–12 years significantly (OR 3.16 CI [2.73, 3.65]). Conclusion: Overweight not in the first year of life, but at age 7 years was more predictive for DEBs. [ABSTRACT FROM AUTHOR]

Background: Poor growth during infancy and childhood is a characteristic feature of cystic fibrosis (CF). However, the impact of CF on intrauterine growth is unclear. We studied the effect of CF on birth weight in Denmark and Wales, and assessed whether any associations are due to differences in gestational age at birth.Methods: We conducted national registry linkage studies in two countries, using data for 2.2 million singletons born in Denmark (between 1980 and 2010) and Wales (between 1998 and 2015). We used hospital inpatient and outpatient data to identify 852 children with CF. Using causal mediation methods, we estimated the direct and indirect (via gestational age) effect of CF on birth weight after adjustment for sex, parity and socioeconomic background. We tested the robustness of our results by adjusting for additional factors such as maternal smoking during pregnancy in subpopulations where these data were available.Results: Babies with CF were more likely to be born preterm and with low birth weight than babies with no CF (12.7% vs 5% and 9.4% vs 5.8% preterm; 11.9% vs 4.2% and 11% vs 5.4% low birth weight in Denmark and Wales, respectively). Using causal mediation methods, the total effect of CF on birth weight was estimated to be -178.8 g (95% CI -225.43 to -134.47 g) in the Danish population and -210.08 g (95% CI -281.97 to -141.5 g) in the Welsh population. About 40% of this effect of CF on birth weight was mediated through gestational age.Conclusions: CF significantly impacts on intrauterine growth and leads to lower birth weight in babies with CF, which is only partially explained by shorter gestation. [ABSTRACT FROM AUTHOR]

Prenatal exposure to fever and infections has been linked to various neurodevelopmental disorders, but it is not yet known whether more subtle effects on neurodevelopment may exist as well. Therefore, we aimed to investigate whether these early-life exposures were associated with academic performance in childhood and early adolescence. Children and mothers who were enrolled in the Danish National Birth Cohort during 1996-2002 were included in this study. Information on fever and infections common in pregnancy was prospectively collected in 2 pregnancy interviews and linked with assessments of academic performance from the 2010-2013 Danish National Tests. Hierarchical multilevel linear regression of 216,350 assessments made in 71,850 children born to 67,528 mothers revealed no differences in academic performance among the children according to prenatal exposure to fever (odds ratio (OR) = 1.01, 95% confidence interval (CI): 1.00,1.03), any infection (OR = 1.00, 95% CI: 0.99, 1.01), genitourinary infection (OR = 1.01, 95% CI: 0.99, 1.02), prolonged cough (OR = 1.00, 95% CI: 0.99, 1.02), or diarrhea (OR = 0.99, 95% CI: 0.97, 1.00). The findings were supported in different types of academic as-sessments, with different timings of exposure, and in sibling comparisons. This large population-based study suggested that prenatal exposure to fever and common infections does not affect the child's basic school performance. [ABSTRACT FROM AUTHOR]

Objective: Our aim was to study the relation between the duration of full and any breastfeeding and risk of type 1 diabetes.Research Design and Methods: We included two population-based cohorts of children followed from birth (1996-2009) to 2014 (Denmark) or 2015 (Norway). We analyzed data from a total of 155,392 children participating in the Norwegian Mother and Child Cohort Study (MoBa) and the Danish National Birth Cohort (DNBC). Parents reported infant dietary practices when their child was 6 and 18 months old. The outcome was clinical type 1 diabetes, ascertained from nationwide childhood diabetes registries. Hazard ratios (HRs) were estimated using Cox regression.Results: Type 1 diabetes was identified in 504 children during follow-up, and the incidence of type 1 diabetes per 100,000 person-years was 30.5 in the Norwegian cohort and 23.5 in the Danish cohort. Children who were never breastfed had a twofold increased risk of type 1 diabetes compared with those who were breastfed (HR 2.29 [95% CI 1.14-4.61] for no breastfeeding vs. any breastfeeding for ≥12 months). Among those who were breastfed, however, the incidence of type 1 diabetes was independent of duration of both full breastfeeding (HR per month 0.99 [95% CI 0.97-1.01]) and any breastfeeding (0.97 [0.92-1.03]).Conclusions: Suggestive evidence supports the contention that breastfeeding reduces the risk of type 1 diabetes. Among those who were breastfed, however, no evidence indicated that prolonging full or any breastfeeding was associated with a reduced risk of type 1 diabetes. [ABSTRACT FROM AUTHOR]

Background: Cardiovascular (CVD) complications stemming from vascular dysfunction have been widely explored in the setting of preeclampsia. However, the impact of abruption, a strong indicator of microvascular disturbance, on the risk of CVD mortality and morbidity remains poorly characterised.Methods: We designed a cohort analysis of 828 289 women who delivered singletons in Denmark between 1978 and 2010. We linked the National Patient Registry and the Registry of Causes of Death to the Danish Birth Registry to ascertain CVD events. We estimated CVD risks in relation to abruption from Cox proportional hazards regression following adjustments for confounders.Results: With 13 231 562 person-years of follow-up of women with at least one delivery, 11 829 pregnancies were complicated by abruption. The median (interquartile range) follow-up in the non-abruption and abruption groups was 16 (8, 24) and 18 (10, 25) years, respectively. CVD mortality rates in women with and without abruption were 0.9 and 0.3 per 10 000 person-years, respectively (adjusted hazard ratio (HR) 2.7, 95% confidence interval (CI) 1.5, 5.0). The corresponding CVD morbidity complication rates were 16.7 and 10.0 per 10 000 person-years, respectively (HR 1.5, 95% CI 1.4, 1.8). The increased risks were evident for ischaemic heart disease, acute myocardial infarction, hypertensive heart disease, non-rheumatic valvular disease, and congestive heart failure.Conclusions: This study shows increased hazards of CVD morbidity and mortality in relation to abruption. A better understanding of the pathogenesis of distorted placental microvasculature is needed as this appears to be a harbinger of CVD later in life. [ABSTRACT FROM AUTHOR]

Background Fever and infections are common events during pregnancy, and have been shown to be associated with neurodevelopmental impairment in the offspring. The evidence in relation to attention deficit/hyperactivity disorder ( ADHD) is, however, nonexistent for fever and limited for infections. The aim of this study was therefore to investigate the impact of these exposures on the occurrence of ADHD in the offspring, considering gestational timing as well as intensity of exposure. Methods The study was conducted within the Danish National Birth Cohort, using data on 89,146 pregnancies enrolled during 1996-2002. Exposure to fever and infections were assessed prospectively in two computer-assisted telephone interviews during pregnancy and ADHD status in the child was determined using registry information from three nation-wide patient and prescription registers. Stratified Cox regressions were used to calculate adjusted hazard ratios of ADHD occurrence. Results The analyses revealed no overall association between maternal exposure to fever or infections and ADHD in the offspring [adjusted hazard ratio ( aHR): 1.03, 95% confidence interval ( CI): 0.93-1.13 and aHR: 1.01, 95% CI: 0.92-1.11]. When the exposures were considered during specific gestational periods, increased rates of ADHD were observed following fever in gestational weeks 9-12 ( aHR: 1.33, 95% CI: 1.12-1.58), and genitourinary infections in weeks 33-36 ( aHR: 1.60, 95% CI: 1.13-2.26). Conclusions Although no overall adverse association between fever and infections in pregnancy and ADHD in the offspring was found, the analyses indicated that exposures during specific time windows of the pregnancy could be associated with increased ADHD occurrence. [ABSTRACT FROM AUTHOR]

Abstract Children exposed to socioeconomic adversity have elevated levels of psychological difficulties immediately and long-term. However, few studies have examined the consequences of long-term patterns of dynamic trajectories of family income. The Danish National Birth Cohort (DNBC) is a longitudinal, population-based birth cohort study (1996–2002). Data on household poverty from the year before birth until the child was 10 years of age (n = 12 measures) were obtained from the National Danish Registries and modeled using semiparametric group-based modeling. Child mental health symptoms were measured at 11 years using mother and child-reported Strengths and Difficulties Questionnaires (n = 40 192), and the child-reported Stress in Childhood (SiC) scale (n = 46 284). Four categories of family socioeconomic position were identified: 1) No poverty (83.5%); 2) Intermittent poverty, representing families who alternate between being above and below the poverty cut-off (8.6%); 3) Poverty during the perinatal period (4.9%); and 4) Chronic poverty (3.0%). Controlling for several early life characteristics of the family, mother and child, intermittent poverty vs. no poverty was consistently associated with child psychological difficulties (any problem: RR = 1.38, 95% CI: 1.16–1.64; conduct problems: RR = 1.38, 95% CI: 1.16–1.64; and stress: RR = 1.07, 95% CI: 1.02–1.12). An association was also found between perinatal poverty and children's symptoms of hyperactivity/inattention (RR = 1.28, 95% CI = 1.03; 1.59). We found no associations between chronic poverty and any of the outcome measures when adjusting for early life risk factors. Children growing up in households characterized by financial instability have elevated levels of psychosocial symptoms, especially externalizing behaviors, as well as stress in early adolescence. Highlights • Intermittent child poverty associated with later externalizing symptoms and stress. • Perinatal period poverty associated with later hyperactivity/inattention. • Social policies should aim to ensure long-term income stability for families. [ABSTRACT FROM AUTHOR]