Associations of light exposure patterns with sleep among Dutch children: The ABCD cohort study.

Light exposure affects the circadian system and consequently can affect sleep quality. Only few studies examined this relationship in children. We evaluated associations between light exposure patterns and sleep metrics in children. We measured the sleep parameters of 247 Dutch children, aged between 11 and 13 years and recruited from the ABCD cohort, using actigraphy and sleep records for 7 consecutive nights. Personal light exposures were measured with a light meter during the whole day and night. We applied generalized mixed-effects regression models, adjusted for possible confounders, to evaluate the associations of light exposure patterns on sleep duration, sleep efficiency and sleep-onset delay. In the models mutually adjusted for potential confounders, we found the amount of hours between the first time of bright light in the morning and going to sleep and the duration of bright light to be significantly associated with decreased sleep duration (in min; ß: -2.02 [95% confidence interval: -3.84, -0.25], ß: -8.39 [95% confidence interval: -16.70, -0.07], respectively) and with shorter sleep-onset delay (odds ratio: 0.88 [95% confidence interval: 0.80, 0.97], odds ratio: 0.40 [95% confidence interval: 0.19, 0.87], respectively). Increased light intensities at night were associated with decreased sleep duration (T2 ß: -8.54 [95% confidence interval: -16.88, -0.20], T3 ß: -14.83 [95% confidence interval: -28.04, -1.62]), while increased light intensities before going to bed were associated with prolonged sleep onset (odds ratio: 4.02 [95% confidence interval: 2.09, 7.73]). These findings further suggest that children may be able to influence their sleep quality by influencing the light exposure patterns during day and night.

Long-term cardiometabolic health in people born after assisted reproductive technology: a multi-cohort analysis.

AIMS: To examine associations of assisted reproductive technology (ART) conception (vs. natural conception: NC) with offspring cardiometabolic health outcomes and whether these differ with age. METHODS AND RESULTS: Differences in systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), lipids, and hyperglycaemic/insulin resistance markers were examined using multiple linear regression models in 14 population-based birth cohorts in Europe, Australia, and Singapore, and results were combined using meta-analysis. Change in cardiometabolic outcomes from 2 to 26 years was examined using trajectory modelling of four cohorts with repeated measures. 35 938 (654 ART) offspring were included in the meta-analysis. Mean age ranged from 13 months to 27.4 years but was <10 years in 11/14 cohorts. Meta-analysis found no statistical difference (ART minus NC) in SBP (-0.53 mmHg; 95% CI:-1.59 to 0.53), DBP (-0.24 mmHg; -0.83 to 0.35), or HR (0.02 beat/min; -0.91 to 0.94). Total cholesterol (2.59%; 0.10-5.07), HDL cholesterol (4.16%; 2.52-5.81), LDL cholesterol (4.95%; 0.47-9.43) were statistically significantly higher in ART-conceived vs. NC offspring. No statistical difference was seen for triglycerides (TG), glucose, insulin, and glycated haemoglobin. Long-term follow-up of 17 244 (244 ART) births identified statistically significant associations between ART and lower predicted SBP/DBP in childhood, and subtle trajectories to higher SBP and TG in young adulthood; however, most differences were not statistically significant. CONCLUSION: These findings of small and statistically non-significant differences in offspring cardiometabolic outcomes should reassure people receiving ART. Longer-term follow-up is warranted to investigate changes over adulthood in the risks of hypertension, dyslipidaemia, and preclinical and clinical cardiovascular disease.

Early pregnancy triglycerides and not fructosamine are associated with birth weight (with foetal sexual dimorphism).

BACKGROUND: We evaluated whether maternal triglycerides (TGs) or fructosamine (measured in early pregnancy) predominantly contribute to birth weight (BW), in a foetal sexual dimorphism. METHODS: Analysis of data from the Amsterdam Born Children and their Development cohort study (total n = 3514). Maternal nonfasting TGs and fructosamine were determined in early gestation (median 13 weeks). Multivariable linear regression analysis was used to determine whether maternal TGs or fructosamine was associated with BW-small for gestational age (SGA)-large for gestational age (LGA) and whether it was sex-dependent. RESULTS: With each 1 mmol/L increase in TGs, BW increased significantly by 81.7 g. This increase was larger with boys (107.3 g; 95% CI 66-148) than girls (60.5 g; 95% CI 23.6-97.4). No association was found with fructosamine. When including different covariates (gestational age at blood sampling, total duration of pregnancy, maternal height, age, parity, ethnicity, educational level, smoking, alcohol, and pre-pregnancy BMI), 29% of the variance in BW can be explained. Adding fructosamine to this model gave no added value in predicting BW, in contrast to adding TGs (R2 raised from 0.292 to 0.299, p < .001). The odds of a newborn LGA with higher maternal TG were increased (OR 1.6, 95% CI 1.3-2.0), in contrast to fructosamine. CONCLUSIONS: Maternal TGs were more dominant (compared to fructosamine) in its association with BW (measured in early physiological pregnancy) and more prominently present when carrying a male foetus. These remarkable observations warrant more future research, especially in obese patients at risk for gestational diabetes.

Parental Discontent with Infant Sleep During the First Two Years of Life.

BACKGROUND: Problematic sleep in infants can have a high impact on families. We examined parental discontent with infant sleep in the first six months of life and parent-perceived problematic sleep during the second year of life. METHODS: We used Sarphati Cohort data of 1471 children. During periodic youth health care visits in the first six months of life, professionals registered parental discontent with infant sleep. In the second year of life, parents filled out the Brief Infant Sleep Questionnaire (BISQ), from which we defined parent-perceived problematic sleep and BISQ-defined problematic sleep. We examined the association of parental discontent with infant sleep during the first six months with both BISQ-derived outcomes up to age two, using multivariable logistic regression analysis. RESULTS: 26% of parents were discontented with infant sleep during the first six months of life. During the second year of life, 27% of the parents perceived their child's sleep as problematic, and 9% of the infants had BISQ-defined problematic sleep. Early parental discontent with infant sleep was associated with parent-perceived problematic sleep [adjusted OR 2.50 (95% CI 1.91-3.28)], and BISQ-defined problematic sleep [adjusted OR 1.88 (1.11-3.17)]. CONCLUSIONS: Early registered parental discontent with infant sleep was a predictor of parent-perceived problematic sleep in early toddlerhood. Registering parental discontent during infancy might enable professionals to identify a group of infants at risk for later problematic sleep. We recommend screening and parental support for sleep difficulties in an early stage.

Ideal cardiovascular health at age 5-6 years and cardiometabolic outcomes in preadolescence.

BACKGROUND: The American Heart Association (AHA) developed a definition of ideal cardiovascular health (ICH) based on the presence of both ideal health behaviours (diet, physical activity, weight status and smoking) and ideal health factors (glucose, total cholesterol and blood pressure levels). However, research of ICH in the paediatric population is scarce. We aimed to study ICH at age 5-6 years by extending the original ICH score with the health behaviours: sleep duration, screen time and prenatal smoke exposure, and to evaluate its association with cardiometabolic outcomes at age 11-12. METHODS: A total of 1666 children aged 5-6 years were selected from the database of the ABCD-study, a prospective cohort study on the health and development of children born in Amsterdam, the Netherlands. Of these, 846 (50.8%) were boys and 1460 (87.6%) had a healthy weight. Data on self-reported health behaviours and health factors were used to calculate the ICH scores (original and extended) by adding the frequency of scoring 'healthy' on each indicator, based on international cut-offs. The children were followed up for 6 years and cardiometabolic outcomes (carotid intima-media thickness (CIMT), blood pressure, glucose and lipids) were measured. Associations between ICH (both original and extended) and cardiometabolic outcomes were examined using multivariable regression models. RESULTS: At age 5-6 years, 11% scored poor (score 1-5), 56% intermediate (score 6-7) and 33% good (score 8-9) on extended ICH. Healthy diet and normal total cholesterol concentrations were the least prevalent. Neither the original nor the extended ICH scores were associated with CIMT at age 11-12. A higher score on the extended ICH was associated with lower total cholesterol (p for trend < 0.001), lower systolic (p for trend = 0.012) and diastolic blood pressure (p for trend = 0.011), and lower body mass index (BMI) (p < 0.001) at age 11-12. The original ICH score was associated with lower total cholesterol (p < 0.001) and BMI (p < 0.001) only. CONCLUSION: Our findings suggest that extending the ICH score in young children with additional health behaviours improves prediction of some cardiometabolic outcomes, but not CIMT in preadolescence, compared to the original ICH score. We would recommend other researchers to incorporate objective measures of health behaviours and longer follow-up to find out whether associations persist into adulthood.

Psychosocial and peripartum determinants of postpartum depression: Findings from a prospective population-based cohort. The ABCD study.

BACKGROUND: Postpartum depression is prevalent and concerns a serious health problem for women and their families. The current large-scale birth cohort study investigated: (1) the associations of various potential determinants of postpartum depression using a multidimensional approach, and (2) the individual contribution of obstetric and perinatal determinants and pregnancy-specific anxiety to the risk of postpartum depression. METHODS: This study was based on a large-scale birth cohort study in Amsterdam, the Netherlands (ABCD-study). In 5109 women depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (cut-off ≥16 indicating high risk of postpartum depression). Determinants were assessed using self-report or perinatal registries. RESULTS: In the final multivariable model, other-Western and non-Western ethnic background, increased antepartum depressive symptoms, increased antepartum anxiety, increased pregnancy-specific anxiety, being unemployed, poor sleep quality, unwanted pregnancy, abuse, multiparity, and congenital abnormality were all independently related to an increased risk of postpartum depression. The strongest risk factors for postpartum depression were antepartum depressive symptoms (adjusted odds ratio (AOR) = 3.86, 95% confidence interval (CI) 3.02-4.92), having a baby with a congenital abnormality (AOR = 2.33, 95% CI 1.46-3.73), and abuse (AOR = 1.95, 95% CI 1.02-3.73). The final model accounted for 24.5% of the variance. LIMITATIONS: Our dataset did not provide information on social support or maternal and family history of depression. Next to these determinants, future research should include biological factors. CONCLUSIONS: The determinants identified provide opportunities for the development of multidimensional early screening and early intervention strategies for women with an increased risk of postpartum depression.

Maternal verbal aggression in early infancy and child's internalizing symptoms: interaction by common oxytocin polymorphisms.

Genetic predisposition of social sensitivity might affect vulnerability to develop psychopathology after early life stress exposure. This study examined whether maternal verbally aggressive behavior in early infancy interacts with oxytocin polymorphisms in developing internalizing symptoms at ages 5-6 and 11-12. In the Amsterdam-Born-Children-and-their-Development (ABCD) study, a large observational, population-based birth cohort, maternal verbally aggressive behavior was assessed in the 13th postnatal week by a self-report questionnaire. Internalizing symptoms at age 5-6 were assessed by maternal report (N = 969) and internalizing symptoms at age 11-12 were assessed by self-report (N = 750). Data on oxytocin receptor polymorphisms rs53576 and rs2268498 and oxytocin polymorphisms rs2740210 and rs4813627 were collected. If the child was carrier of rs2740210 CA/AA polymorphism, exposure to maternal verbally aggressive behavior (10.6%) was positively associated with general anxiety at age 5-6 and emotional symptoms at age 11-12 (p for interaction = 0.011 and p = 0.015, respectively). If the child was carrier of rs4813627 GG (wild type), exposure to maternal verbally aggressive behavior was negatively associated with anxiety sensitivity and emotional symptoms at age 11-12 (p for interaction = 0.011 and p = 0.022, respectively). After exposure to maternal verbally aggressive behavior in early infancy, oxytocin polymorphisms may partly determine a child's vulnerability to internalizing symptoms.

Maternal environmental risk factors and the development of internalizing and externalizing problems in childhood: The complex role of genetic factors.

The development of problem behavior in children is associated with exposure to environmental factors, including the maternal environment. Both are influenced by genetic factors, which may also be correlated, that is, environmental risk and problem behavior in children might be influenced by partly the same genetic factors. In addition, environmental and genetic factors could interact with each other increasing the risk of problem behavior in children. To date, limited research investigated these mechanisms in a genome-wide approach. Therefore, the goal of this study was to investigate the association between genetic risk for psychiatric and related traits, as indicated by polygenetic risk scores (PRSs), exposure to previously identified maternal risk factors, and problem behavior in a sample of 1,154 children from the Amsterdam Born Children and their Development study at ages 5-6 and 11-12 years old. The PRSs were derived from genome-wide association studies (GWASs) on schizophrenia, major depressive disorder, neuroticism, and wellbeing. Regression analysis showed that the PRSs were associated with exposure to multiple environmental risk factors, suggesting passive gene-environment correlation. In addition, the PRS based on the schizophrenia GWAS was associated with externalizing behavior problems in children at age 5-6. We did not find any association with problem behavior for the other PRSs. Our results indicate that genetic predispositions for psychiatric disorders and wellbeing are associated with early environmental risk factors for children's problem behavior.

The explanatory role of maternal feeding practices: do they explain ethnic differences in body weight of preadolescents?

INTRODUCTION: This study aimed to explore the role of ethnicity and maternal perceived weight status in the association between maternal child feeding practices and childhood Body Mass Index (BMI) at the age of 11-12 years in a multi-ethnic population. METHODS: We collected data on child feeding practices by the validated Child Feeding Questionnaire (CFQ) among 2398 mothers of adolescents (Mage = 11.2, SDage = 0.6). Multivariate linear analyses were used to determine the cross-sectional association between child feeding practices ('Restriction', 'Pressure to eat', and 'Monitoring'), maternal perception of child's weight status, SDS-BMI, and ethnicity. RESULTS: 'Restriction' (ß = 0.16; 95% CI [0.11; 0.20]) and 'Pressure to eat' (ß = -0.32 [-0.36;-0.28]) were significantly associated with child SDS-BMI. Both associations were strongly influenced by the mother's perception of child's weight status. Besides, non-native Dutch mothers performed significantly higher levels of 'Restriction' (M±SD = 12.17 ±â€¯4.41) and 'Pressure to eat' (10.75 ±â€¯4.03) compared to native Dutch mothers (11.25 ±â€¯4.15 and 9.99 ±â€¯3.83, respectively). Native Dutch mothers performed higher levels of 'Monitoring' (17.15 ±â€¯2.54) compared to non-native Dutch mothers (16.73 ±â€¯3.01). Furthermore, children of non-native Dutch mothers had a 0.15 (0.27; 0.46) higher SDS-BMI. Finally, results showed that the association between 'Pressure to eat' and SDS-BMI was stronger in native Dutch mothers (ß = -0.20; 95% CI [-0.24; -0.15]) compared to non-native Dutch mothers (ß = -0.11; 95% CI [-0.18; -0.04]). DISCUSSION AND CONCLUSION: Ethnic differences in childhood BMI seemed to be partially attributable to the maternal perception of her child's weight status. Besides, maternal perception of child's weight appeared to play an important role in the association between maternal child feeding practices and childhood SDS-BMI. Hence, our findings contribute to the growing evidence concerning the bi-directional association between child feeding practices and childhood BMI.

Does early onset asthma increase childhood obesity risk? A pooled analysis of 16 European cohorts.

The parallel epidemics of childhood asthma and obesity over the past few decades have spurred research into obesity as a risk factor for asthma. However, little is known regarding the role of asthma in obesity incidence. We examined whether early-onset asthma and related phenotypes are associated with the risk of developing obesity in childhood.This study includes 21 130 children born from 1990 to 2008 in Denmark, France, Germany, Greece, Italy, The Netherlands, Spain, Sweden and the UK. We followed non-obese children at 3-4 years of age for incident obesity up to 8 years of age. Physician-diagnosed asthma, wheezing and allergic rhinitis were assessed up to 3-4 years of age.Children with physician-diagnosed asthma had a higher risk for incident obesity than those without asthma (adjusted hazard ratio (aHR) 1.66, 95% CI 1.18-2.33). Children with active asthma (wheeze in the last 12 months and physician-diagnosed asthma) exhibited a higher risk for obesity (aHR 1.98, 95% CI 1.31-3.00) than those without wheeze and asthma. Persistent wheezing was associated with increased risk for incident obesity compared to never wheezers (aHR 1.51, 95% CI 1.08-2.09).Early-onset asthma and wheezing may contribute to an increased risk of developing obesity in later childhood.

Maternal vitamin D concentrations are associated with faster childhood reaction time and response speed, but not with motor fluency and flexibility, at the age of 5-6 years: the Amsterdam Born Children and their Development (ABCD) Study.

About 57 % of the pregnant European women have 25-hydroxyvitamin D (25(OH)D) concentrations below 50 nmol/l. However, as data on the impact of gestational vitamin D deficiency on maternal and fetal health are limited, the WHO does not advocate vitamin D supplementation as part of routine antenatal care. We explored associations between first trimester maternal 25(OH)D status and childhood cognition at 5-6 years of age (n 1854, primarily Caucasian). Median serum 25(OH)D was determined at 13 (interquartile range 12-14) weeks of gestation. Childhood attention, motor fluency and flexibility and executive function were assessed using the Amsterdam Neuropsychological Tasks. Restricted cubic splines and linear regression analyses were used to analyse the data while adjusting for many maternal and child related covariates. Higher 25(OH)D status (nmol/l) was associated with better attention and executive functioning as shown by a faster reaction time (ß -0·30 (sd 0·14) ms, P=0·03), faster response speed (ß -0·58 (sd 0·21) ms, P=0·006), and better response speed stability (ß -0·45 (sd 0·17) ms, P=0·009). No associations were observed of serum 25(OH)D with motor fluency and flexibility. Associations were most pronounced among children of African origin (n 205) as compared with those of Caucasian or another origin, for example attention (reaction time, ß -2·06 (sd 0·70) ms, P=0·004) and executive function (response speed, ß -1·95 (sd 0·94) ms, P=0·04). Concluding, maternal 25(OH)D status was significantly associated with childhood attention and executive function, while no associations were observed for 25(OH)D status with motor fluency and flexibility.

Socioeconomic inequalities in psychosocial problems of children: mediating role of maternal depressive symptoms.

Background: Socioeconomically disadvantaged children often have psychosocial problems. This study examined the mediating role of maternal depressive symptoms during pregnancy, infancy and early childhood in the association between maternal education, as indicator of socioeconomic status (SES), and child's psychosocial problems. Methods: Included were 3410 children from the Amsterdam Born Children and their Development (ABCD) study. To assess the child's psychosocial problems at age 5-6 years, mothers and teachers completed the Strengths and Difficulties Questionnaire (SDQ). Maternal depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale and the Depressive Anxiety and Stress Scale 21. Mediation analysis was performed to calculate the direct effect of maternal education on SDQ score and indirect effects through maternal depressive symptoms. Results: The mean mother-reported SDQ total score was significantly higher (P < 0.001) for children of low-educated mothers (6.74 ± 4.41) compared with children of highly educated mothers (4.47 ± 3.73). Levels of maternal depressive symptoms were also higher in low-educated mothers during pregnancy, infancy and early childhood. Maternal depressive symptoms explained 27.5% of the association between maternal education and mother-reported SDQ scores and 22.9% for combined mother/teacher SDQ scores. Maternal depressive symptoms during pregnancy had the strongest indirect effect. Conclusion: Maternal depressive symptoms during pregnancy mediate the association between low maternal education and child's psychosocial problems. Early recognition and treatment of maternal depressive symptoms is important to prevent psychosocial problems in children, especially in those with low education.

The Influence of Meteorological Factors and Atmospheric Pollutants on the Risk of Preterm Birth.

Atmospheric pollutants and meteorological conditions are suspected to be causes of preterm birth. We aimed to characterize their possible association with the risk of preterm birth (defined as birth occurring before 37 completed gestational weeks). We pooled individual data from 13 birth cohorts in 11 European countries (71,493 births from the period 1994-2011, European Study of Cohorts for Air Pollution Effects (ESCAPE)). City-specific meteorological data from routine monitors were averaged over time windows spanning from 1 week to the whole pregnancy. Atmospheric pollution measurements (nitrogen oxides and particulate matter) were combined with data from permanent monitors and land-use data into seasonally adjusted land-use regression models. Preterm birth risks associated with air pollution and meteorological factors were estimated using adjusted discrete-time Cox models. The frequency of preterm birth was 5.0%. Preterm birth risk tended to increase with first-trimester average atmospheric pressure (odds ratio per 5-mbar increase = 1.06, 95% confidence interval: 1.01, 1.11), which could not be distinguished from altitude. There was also some evidence of an increase in preterm birth risk with first-trimester average temperature in the -5°C to 15°C range, with a plateau afterwards (spline coding, P = 0.08). No evidence of adverse association with atmospheric pollutants was observed. Our study lends support for an increase in preterm birth risk with atmospheric pressure.

Mother's education and offspring asthma risk in 10 European cohort studies.

Highly prevalent and typically beginning in childhood, asthma is a burdensome disease, yet the risk factors for this condition are not clarified. To enhance understanding, this study assessed the cohort-specific and pooled risk of maternal education on asthma in children aged 3-8 across 10 European countries. Data on 47,099 children were obtained from prospective birth cohort studies across 10 European countries. We calculated cohort-specific prevalence difference in asthma outcomes using the relative index of inequality (RII) and slope index of inequality (SII). Results from all countries were pooled using random-effects meta-analysis procedures to obtain mean RII and SII scores at the European level. Final models were adjusted for child sex, smoking during pregnancy, parity, mother's age and ethnicity. The higher the score the greater the magnitude of relative (RII, reference 1) and absolute (SII, reference 0) inequity. The pooled RII estimate for asthma risk across all cohorts was 1.46 (95% CI 1.26, 1.71) and the pooled SII estimate was 1.90 (95% CI 0.26, 3.54). Of the countries examined, France, the United Kingdom and the Netherlands had the highest prevalence's of childhood asthma and the largest inequity in asthma risk. Smaller inverse associations were noted for all other countries except Italy, which presented contradictory scores, but with small effect sizes. Tests for heterogeneity yielded significant results for SII scores. Overall, offspring of mothers with a low level of education had an increased relative and absolute risk of asthma compared to offspring of high-educated mothers.

Excessive infant crying doubles the risk of mood and behavioral problems at age 5: evidence for mediation by maternal characteristics.

The onset of behavioral problems starts in early life. This study examined whether excessive infant crying (maternal ratings) is a determinant of emotional and behavioral problems at age 5-6 years. In the Amsterdam Born Children and their Development (ABCD) study, a large prospective, observational, population-based multiethnic birth cohort, excessive infant crying (crying for three or more hours per 24 h day over the past week) during the 13th week after birth (range 11-25 weeks, SD 2 weeks), maternal burden of infant care and maternal aggressive behavior (either angry speaking, or physical aggression) was assessed using a questionnaire. Children's behavioral and emotional problems at the age of 5-6 were assessed by Goodman's Strengths and Difficulties Questionnaire (SDQ), by the subscale of generalized anxiety of the preschool anxiety scale (PAS), and by the Short Mood and Feelings Questionnaire (SMFQ). Inclusion criterion was singleton birth. Exclusion criteria were preterm born babies or congenital disorders. Among 3389 children, excessive infant crying (n = 102) was associated with a twofold increased risk of the overall problem behavior, conduct problems, hyperactivity, and mood problems at the age of 5-6 [ORs between 1.75 (95 % CI 1.09-2.81) and 2.12 (95 % CI 1.30-3.46)]. This association was mediated by maternal burden of infant care (change in odds' ratio 1-17 %) and maternal aggressive behavior (change in odds' ratio 4-10 %). There was no effect modification by the child's gender or maternal parity. Excessive infant crying was not associated with general anxiety problems. Excessive infant crying doubles the risk of behavioral, hyperactivity, and mood problems at the age of 5-6, as reported by their mother. Maternal burden of infant care partially mediates the association between excessive crying and behavioral and mood problems. Special care for mothers with a high burden of care for their excessive crying infant, notwithstanding their own good health, can be a feasible strategy for possible prevention of mood and behavioral problems in their children later in life.

Risk factors and a clinical prediction model for low maternal thyroid function during early pregnancy: two population-based prospective cohort studies.

BACKGROUND: Low maternal thyroid function during early pregnancy is associated with various adverse outcomes including impaired neurocognitive development of the offspring, premature delivery and abnormal birthweight. AIM: To aid doctors in the risk assessment of thyroid dysfunction during pregnancy, we set out to investigate clinical risk factors and derive a prediction model based on easily obtainable clinical variables. METHODS: In total, 9767 women during early pregnancy (≤18 week) were selected from two population-based prospective cohorts: the Generation R Study (N = 5985) and the ABCD study (N = 3782). We aimed to investigate the association of easily obtainable clinical subject characteristics such as maternal age, BMI, smoking status, ethnicity, parity and gestational age at blood sampling with the risk of low free thyroxine (FT4) and elevated thyroid stimulating hormone (TSH), determined according to the 2·5th-97·5th reference range in TPOAb negative women. RESULTS: BMI, nonsmoking and ethnicity were risk factors for elevated TSH levels; however, the discriminative ability was poor (range c-statistic of 0·57-0·60). Sensitivity analysis showed that addition of TPOAbs to the model yielded a c-statistic of 0·73-0·75. Maternal age, BMI, smoking, parity and gestational age at blood sampling were risk factors for low FT4, which taken together provided adequate discrimination (range c-statistic of 0·72-0·76). CONCLUSIONS: Elevated TSH levels depend predominantly on TPOAb levels, and prediction of elevated TSH levels is not possible with clinical characteristics only. In contrast, the validated clinical prediction model for FT4 had high discriminative value to assess the likelihood of low FT4 levels.

The association of birth weight and postnatal growth with energy intake and eating behavior at 5 years of age - a birth cohort study.

BACKGROUND: Low and high birth weight and accelerated postnatal weight gain are associated with an increased risk of obesity. Perinatal effects on energy intake and eating behavior have been proposed as underlying mechanisms. This study aimed to examine the independent associations of birth weight and postnatal weight and height gain with childhood energy intake and satiety response. METHODS: In a birth cohort study, we used data from 2227 children (52% male), mean age 5.6 (±0.4) years. Mean daily energy intake and satiety response were parent-reported through validated questionnaires. Exposures were birth weight z-score and conditional weight and height gain between 0-1, 1-3, 3-6, 6-12 months and 12 months to 5 years. Conditional weight and height are residuals of current weight and height regressed on prior growth data, to represent deviations from expected growth. Analyses were adjusted for a set of potential confounding variables. RESULTS: Conditional weight gain between 1-3, 3-6 months and 12 months to 5 years was significantly associated with energy intake, with 29.7 (95%-CI: 4.6; 54.8), 24.0 (1.8; 46.1) and 79.5 (29.4; 129.7) kcal/day more intake for each Z-score conditional weight gain between 1-3, 3-6 months and 12 months to 5 years, respectively. Conditional height gain between 0-1, 1-3 months and 12 months to 5 years was negatively associated with energy intake (ß: -42.0 [66.6; -17.4] for 0-1 months, -35.1 [-58.4; -11.8] for 1-3 months and -37.4 [-72.4; -2.3] for 12 months to 5 years). Conditional weight gain in all periods was negatively associated with satiety response, with effect sizes from - 0.03 (-0.06; -0.002) in early infancy to -0.12 (-0.19; -0.06) in childhood. Birth weight was not associated with energy intake or satiety response. CONCLUSIONS: Our findings suggest that accelerated infant and childhood weight gain are associated with increased energy intake and diminished satiety response at 5 years. Accelerated height gain seems to be beneficial for childhood energy intake. This perinatal 'programming' of energy intake and eating behavior provide a potential mechanism linking early life influences with later obesity and cardiovascular disease.

Impact of Low Maternal Education on Early Childhood Overweight and Obesity in Europe.

BACKGROUND: Comparable evidence on adiposity inequalities in early life is lacking across a range of European countries. This study investigates whether low maternal education is associated with overweight and obesity risk in children from distinct European settings during early childhood. METHODS: Prospective data of 45 413 children from 11 European cohorts were used. Children's height and weight obtained at ages 4-7 years were used to assess prevalent overweight and obesity according to the International Obesity Task Force definition. The Relative/Slope Indices of Inequality (RII/SII) were estimated within each cohort and by gender to investigate adiposity risk among children born to mothers with low education as compared to counterparts born to mothers with high education. Individual-data meta-analyses were conducted to obtain aggregate estimates and to assess heterogeneity between cohorts. RESULTS: Low maternal education yielded a substantial risk of early childhood adiposity across 11 European countries. Low maternal education yielded a mean risk ratio of 1.58 (95% confidence interval (CI) 1.34, 1.85) and a mean risk difference of 7.78% (5.34, 10.22) in early childhood overweight, respectively, measured by the RII and SII. Early childhood obesity risk by low maternal education was as substantial for all cohorts combined (RII = 2.61 (2.10, 3.23)) and (SII = 4.01% (3.14, 4.88)). Inequalities in early childhood adiposity were consistent among boys, but varied among girls in a few cohorts. CONCLUSIONS: Considerable inequalities in overweight and obesity are evident among European children in early life. Tackling early childhood adiposity is necessary to promote children's immediate health and well-being and throughout the life course.

Outdoor and indoor sources of residential radiofrequency electromagnetic fields, personal cell phone and cordless phone use, and cognitive function in 5-6 years old children.

BACKGROUND: Little is known about the exposure of young children to radiofrequency electromagnetic fields (RF-EMF) and potentially associated health effects. We assessed the relationship between residential RF-EMF exposure from mobile phone base stations, residential presence of indoor sources, personal cell phone and cordless phone use, and children's cognitive function at 5-6 years of age. METHODS: Cross-sectional study on children aged 5-6 years from the Amsterdam Born Children and their Development (ABCD) study, the Netherlands (n=2354). Residential RF-EMF exposure from mobile phone base stations was estimated with a 3D geospatial radio wave propagation model. Residential presence of indoor sources (cordless phone base stations and Wi-Fi) and children's cell phone and cordless phone use was reported by the mother. Speed of information processing, inhibitory control, cognitive flexibility, and visuomotor coordination was assessed using the Amsterdam Neuropsychological Tasks. RESULTS: Residential presence of RF-EMF indoor sources was associated with an improved speed of information processing. Higher residential RF-EMF exposure from mobile phone base stations and presence of indoor sources was associated with an improved inhibitory control and cognitive flexibility whereas we observed a reduced inhibitory control and cognitive flexibility with higher personal cordless phone use. Higher residential RF-EMF exposure from mobile phone base stations was associated with a reduced visuomotor coordination whereas we observed an improved visuomotor coordination with residential presence of RF-EMF indoor sources and higher personal cell phone use. CONCLUSIONS: We found inconsistent associations between different sources of RF-EMF exposure and cognitive function in children aged 5-6 years.

Inclusion of migrants and ethnic minorities in European birth cohort studies-a scoping review.

BACKGROUND: Migrant and ethnic minority groups constitute substantial parts of European populations. They frequently experience health disadvantages relative to the respective majority populations. Birth cohort studies can help to disentangle social and biological factors producing these health inequalities over the life course. We investigated whether birth cohorts in European countries (i) assess migration history and ethnicity in the study design; and (ii) use this information in data analyses. METHODS: A scoping review was performed in which European birth cohort studies were identified using dedicated web-based registries, MEDLINE and EMBASE. Two reviewers systematically assessed all identified birth cohorts and selected those fulfilling defined inclusion criteria (e.g. enrolment after 1980). Publications and websites were screened for information on the inclusion of migrants and ethnic minorities. To obtain more detailed information, researchers of enrolled birth cohorts were contacted individually. RESULTS: Eighty-eight birth cohorts were identified in 20 European countries, with more than 486 250 children enrolled in total. Sixty-two studies (70.5%) reported collecting data about migration history or ethnic background. Twenty-three studies (26%) used information on migration history or ethnicity for data analyses or plan to do so in future. CONCLUSION: The majority of European birth cohorts assessed participants' migration history or ethnic background; however, this information was seldom used for comparative analyses in trying to disentangle reasons for health inequalities. Also, heterogeneous indicators were used. Better use of data already available, as well as harmonization of data collection on migration history and ethnicity, could yield interesting insights into the production of health inequalities.