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Short sleep duration has been linked to adverse behavioral and cognitive outcomes in schoolchildren, but few studies examined this relation in preschoolers. We aimed to investigate the association between parent-reported sleep duration at 3.5 years and behavioral and cognitive outcomes at 5 years in European children. We used harmonized data from five cohorts of the European Union Child Cohort Network: ALSPAC, SWS (UK); EDEN, ELFE (France); INMA (Spain). Associations were estimated through DataSHIELD using adjusted generalized linear regression models fitted separately for each cohort and pooled with random-effects meta-analysis. Behavior was measured with the Strengths and Difficulties Questionnaire. Language and non-verbal intelligence were assessed by the Wechsler Preschool and Primary Scale of Intelligence or the McCarthy Scales of Children's Abilities. Behavioral and cognitive analyses included 11,920 and 2981 children, respectively (34.0%/13.4% of the original sample). In meta-analysis, longer mean sleep duration per day at 3.5 years was associated with lower mean internalizing and externalizing behavior percentile scores at 5 years (adjusted mean difference: − 1.27, 95% CI [− 2.22, − 0.32] / − 2.39, 95% CI [− 3.04, − 1.75]). Sleep duration and language or non-verbal intelligence showed trends of inverse associations, however, with imprecise estimates (adjusted mean difference: − 0.28, 95% CI [− 0.83, 0.27] / − 0.42, 95% CI [− 0.99, 0.15]). This individual participant data meta-analysis suggests that longer sleep duration in preschool age may be important for children's later behavior and highlight the need for larger samples for robust analyses of cognitive outcomes. Findings could be influenced by confounding or reverse causality and require replication. [ABSTRACT FROM AUTHOR]

Background: There is a need to test the fetal programming theoretical framework in nutritional epidemiology. We evaluated whether maternal seafood intake during pregnancy was associated with 8-year-old attention outcomes after adjusting for previous child seafood intake and cognitive function. We also explored effect modification by several single nucleotide polymorphisms (SNPs) related with polyunsaturated fatty acid (PUFA) metabolism.Methods: Our final analyses included 1644 mother-child pairs from the prospective INMA (INfancia y Medio Ambiente) cohort study (Spain, recruitment between 2003 and 2008). We used food frequency questionnaires to assess prenatal and postnatal seafood consumption of the mother-child pairs. We evaluated attention function of the children through the computer-based Attention Network Test (ANT) and we used the number of omission errors and the hit reaction time standard error (HRT-SE). Parents reported child attention deficit hyperactivity disorder (ADHD) symptoms using the Revised Conners' Parent Rating Scale Short Form (CPRS-R: S). We measured seven candidate SNPs in a subsample of 845 children. We estimated associations using regression models, adjusting for family characteristics, child seafood intake and cognitive functions at early ages, and to explore SNP effect modifications.Results: Higher total seafood intake during early pregnancy was associated with a reduction of child ANT omission errors, 5th quintile (median = 854 g/week) vs 1st quintile (median = 195 g/week), incidence risk ratio (IRR) 0.76; 95% CI = 0.61, 0.94. Similar results were observed after adjusting the models for child seafood intake and previous cognitive status. Lean, large and small fatty fish showed similar results, and generally similar but less robust associations were observed with the other attention outcomes. Shellfish and canned tuna showed weaker associations. The association patterns were weaker in late pregnancy and null in child seafood consumption. Child rs1260326 (glucokinase regulator, GCKR) and child/maternal rs2281591 (fatty acid elongase 2, ELOVL2) polymorphisms showed nominal P-value for interactions <0.10 between total seafood intake and ANT outcomes.Conclusions: After adjusting for previous child cognitive functions and child seafood intake, high pregnancy consumption (total, lean, small and large fatty fish) was independently associated with improvements of some 8-year-old attention outcomes. Genetic effect modification analyses suggest PUFA intake from seafood as a potential biological mechanism of such association. [ABSTRACT FROM AUTHOR]

The aim of this study is to understand the association between prenatal, newborn and postnatal head circumference (HC) and preschool neurodevelopment in a large population-based birth cohort. The INMA project followed 1795 children from 12 weeks of pregnancy to preschool years. HC measurements were carried out prospectively, and following a standardized protocol during pregnancy (12, 20 and 34 weeks), birth, and child ages of 1-1.5 and 4 years old; and z-scores were further estimated. Prenatal head growth was assessed using conditional z-scores between weeks 12-20 and 20-34. Several neuropsychological tests [MSCA (cognition), CPT (attention)] and behavioral rating scales [DSM-IV-ADHD, CAST (autism), CPSCS (social competence)] were carried out during the last follow-up (5 years old). Multivariable models adjusted for family and child characteristics were applied to analyze associations between HC and neurodevelopment. In fully adjusted models, prenatal HC and head growth showed little or no associations with the neurodevelopment outcomes. Independent associations were observed between HC z-scores at birth, 1-1.5 years and 4 years and MSCA global cognitive scores and DSM-IV inattention symptoms. Specifically, z-score at birth was positively associated with general cognitive scores [β 1.22, 95% confidence interval (CI) 0.59, 1.85], and we observed a protective association with ADHD-DSM-IV total symptoms, mean ratio (MR) 0.85 (0.75, 0.96). Prenatal HC and head growth measurements gave little information about child cognitive abilities and behavior at preschool years. However, HC at birth and early childhood was positively associated with a range of neuropsychological outcomes, including protective associations with ADHD symptoms. [ABSTRACT FROM AUTHOR]

Purpose: Median urinary iodine concentration (UIC) is used to describe the iodine status of a population. However, the link between UIC and iodine intake may vary during pregnancy. The aim of this study was to compare UIC during and after pregnancy, adjusting for factors that affect iodine intake.Methods: Two repeated measures of UIC and data on maternal iodine intake estimated through questionnaires were collected during pregnancy and 1-4 years after pregnancy in a subsample of women (n = 598) from a mother and child cohort study in Spain. Random-effects interval regression was used to assess the changes in UIC according to pregnancy status.Results: Median UIC was similar during (133 μg/L) and after pregnancy (139 μg/L). After adjusting for iodised salt, iodine supplement consumption, and socio-demographic related variables, UIC was 24.0% (95% CI 11.3, 38.2) higher after than during pregnancy. This difference was maintained in a subsample of women with exhaustive information on diet (n = 291): 26.2%, 95% CI 10.3, 44.4.Conclusions: In an iodine sufficient area for the general population, iodine excretion was lower during than after pregnancy when factors affecting iodine intake were controlled for. Current recommendations of median UIC during pregnancy are based on the equivalence between iodine intake and UIC estimated from studies in non-pregnant populations, which might lead to overestimation of iodine deficiency during gestation. Further studies should evaluate the equivalence between iodine intake and its urinary excretion during pregnancy. [ABSTRACT FROM AUTHOR]

Objective The aim of the study was to identify factors associated with non-initiation and cessation of predominant breastfeeding (PBF) in a mother-child cohort from Spain. Materials and Methods The analysis included 2195 mother-infant from birth to 14 months post- delivery recruited between 2004 and 2008. Maternal characteristics were collected during the pregnancy. Lactation data were obtained at 6 and 14 months after delivery. PBF was defined as intake of breast milk plus liquids like juices or water. The PBF cessation was calculated using the date that women started PBF and the date that she reported to start giving infant formula and/or food. The relationship between maternal variables and PBF initiation and cessation was modeled using logistic and Cox proportional hazards regression analysis. Results The prevalence of PBF at hospital discharge was 85.3, 53.4% at 3 months, 46.1% at 4 months and 7.2% at 6 month. Only two women continued PBF at 12 months and none at 14 months. The initiating of PBF was associated with higher levels of maternal education, being a first-time mother and worked in a non-manual occupation. Higher level of physical activity, not smoking and having a healthy BMI, were also positively associated with PBF initiation. PBF cessation was higher in young, obese women, who had had complications during the pregnancy, and who had lower levels of education and smoked. The employment status of women, in week 32 of pregnancy and also in month 14 post-delivery, determined likelihood of PBF cessation. Conclusions Healthier habits and education positively influenced PBF initiation and duration. Decrease in PBF duration rates in Spain can be interpreted in part as a consequence of women returning to work. [ABSTRACT FROM AUTHOR]

BACKGROUND: Studies have reported some evidence of adverse effects of organochlorine exposures on child development, but the results have been inconsistent, and few studies have evaluated associations with child behavior. OBJECTIVE: We investigated the association between prenatal and early-life exposures to 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153) and 1,1- dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE) and behaviors in children between 5 and 9 y of age. METHODS: In the Biopersistent organochlorines in diet and human fertility: Epidemiologic studies of time to pregnancy and semen quality in Inuit and European populations (INUENDO) cohort, consisting of mother-child pairs from Greenland and Ukraine (n = 1,018), maternal serum PCB-153 and p,p'-DDE concentrations were measured during pregnancy, and cumulative postnatal exposures during the first 12 months after delivery were estimated using a pharmacokinetic model. Parents completed the Strengths and Difficulties Questionnaire (SDQ), and children's behaviors were dichotomized as abnormal (high) versus normal/borderline for five SDQ subscales and the total difficulties score. RESULTS: The total difficulties score, an overall measure of abnormal behavior, was not clearly associated with pre- or postnatal exposures to PCB-153 or to p,p'-DDE. However, pooled adjusted odds ratios (ORs) for high conduct problem scores with a doubling of exposure were 1.19 (95% CI: 0.99, 1.42) and 1.16 (95% CI: 0.96, 1.41) for pre- and postnatal PCB-153, respectively, and 1.25 (95% CI: 1.04, 1.51) and 1.24 (95% CI: 1.01, 1.51) for pre- and postnatal p,p'-DDE, respectively. Corresponding ORs for high hyperactivity scores were 1.24 (95% CI: 0.94, 1.62) and 1.08 (95% CI: 0.81, 1.45) for pre- and postnatal PCB-153, respectively, and 1.43 (95% CI: 1.06, 1.92) and 1.27 (95% CI: 0.93, 1.73) for pre- and postnatalp,p'-DDE, respectively. CONCLUSION: Prenatal and early postnatal exposures to p,p'-DDE and PCB-153 were associated with a higher prevalence of abnormal scores for conduct and hyperactivity at 5-9 y of age in our study population. These findings provide further support for the importance of minimizing organochlorine exposures to young children and to women of childbearing age. [ABSTRACT FROM AUTHOR]

Background: The benefits of the use of folic acid supplements (FASs) during the periconception period to prevent neural tube defects and to ensure normal brain development in offspring are well known. There is concern, however, about the long-term effects of the maternal use of high dosages of FASs that exceed the Tolerable Upper Intake Level (UL) (≥1000 µg/d) on child neurocognitive outcomes. Objective: The objective of the study was to examine the association between the use of high dosages of FASs during pregnancy and child neuropsychological development at ages 4-5 y. Design: The multicenter prospective mother-child cohort study, the Infancia y Medio Ambiente (INMA) Project, was conducted in 4 regions of Spain: Asturias, Sabadell, Gipuzkoa, and Valencia. Pregnant women were recruited between 2003 and 2008. Data on 1682 mother-child pairs were included in the final analyses. The pregnant women completed an interviewer-administered questionnaire that was validated to estimate typical dietary folate intake and the use of FASs at 10-13 and 28-32 wk of gestation. Neuropsychological development scores at 4-5 y of age were estimated with the use of the McCarthy Scales of Children's Abilities. Multiple linear regression and meta-analysis were used to obtain combined-effect estimates. Results: During the periconception period, one-third of the women (n = 502) took FAS dosages ≥1000 μg/d. The use of FAS dosages ≥1000 µg/d in this period was negatively associated with several neuropsychological outcomes scores in children: global verbal (β = -2.49; 95% CI: -4.71, -0.27), verbal memory (β = -3.59; 95% CI: -6.95, -0.23), cognitive function of posterior cortex (β = -2.31; 95% CI: -4.45, -0.18), and cognitive function of left posterior cortex (β = -3.26; 95% CI: -5.51, -1.01). Conclusions: The use of FAS dosages exceeding the UL (≥1000 µg/d) during the periconception period was associated with lower levels of cognitive development in children aged 4-5 y. The use of FAS dosages ≥1000 µg/d during pregnancy should be monitored and prevented as much as possible, unless medically prescribed. [ABSTRACT FROM AUTHOR]

BACKGROUND: Exposure to traffic noise has been associated with adverse effects on neuro-psychological outcomes in children, but findings with regard to behavioral problems are inconsistent. OBJECTIVE: We investigated whether residential road traffic noise exposure is associated with behavioral problems in 7-year-old children. METHODS: We identified 46,940 children from the Danish National Birth Cohort with complete information on behavioral problems at 7 years of age and complete address history from conception to 7 years of age. Road traffic noise (Lden) was modeled at all present and historical addresses. Behavioral problems were assessed by the parent-reported Strengths and Difficulties Questionnaire (SDQ). Associations between pregnancy and childhood exposure to noise and behavioral problems were analyzed by multinomial or logistic regression and adjusted for potential confounders. RESULTS: A 10-dB increase in average time-weighted road traffic noise exposure from birth to 7 years of age was associated with a 7% increase (95% CI: 1.00, 1.14) in abnormal versus normal total difficulties scores; 5% (95% CI: 1.00, 1.10) and 9% (95% CI: 1.03, 1.18) increases in borderline and abnormal hyperactivity/inattention subscale scores, respectively; and 5% (95% CI: 0.98, 1.14) and 6% (95% CI: 0.99, 1.12) increases in abnormal conduct problem and peer relationship problem subscale scores, respectively. Exposure to road traffic noise during pregnancy was not associated with child behavioral problems at 7 years of age. CONCLUSIONS: Residential road traffic noise in early childhood may be associated with behavioral problems, particularly hyperactivity/inattention symptoms. [ABSTRACT FROM AUTHOR]

Background: Green spaces have been associated with improved mental health in children; however, available epidemiological evidence on their impact on child behavioral development is scarce. Objectives: We investigated the impact of contact with green spaces and blue spaces (beaches) on indicators of behavioral development and symptoms of attention deficit/hyperactivity disorder (ADHD) in schoolchildren. Methods: This study was based on a sample of 2,111 schoolchildren (7–10 years of age) from 36 schools in Barcelona in 2012. We obtained data on time spent in green spaces and beaches and Strengths and Difficulties Questionnaires (SDQ) from parents, and ADHD/DSM-IV questionnaires from teachers. Surrounding greenness was abstracted as the average Normalized Difference Vegetation Index (NDVI) in buffers of 100 m, 250 m, and 500 m around each home address. Proximity to green spaces was defined as living within 300 m of a major green space (≥ 0.05 km2). We applied quasi-Poisson mixed-effects models (with school random effect) to separately estimate associations between indicators of contact with green spaces and SDQ and ADHD total and subscale scores. Results: We generally estimated beneficial associations between behavioral indicators and longer time spent in green spaces and beaches, and with residential surrounding greenness. Specifically, we found statistically significant inverse associations between green space playing time and SDQ total difficulties, emotional symptoms, and peer relationship problems; between residential surrounding greenness and SDQ total difficulties and hyperactivity/inattention and ADHD/DSM-IV total and inattention scores; and between annual beach attendance and SDQ total difficulties, peer relationship problems, and prosocial behavior. For proximity to major green spaces, the results were not conclusive. Conclusion: Our findings support beneficial impacts of contact with green and blue spaces on behavioral development in schoolchildren. [ABSTRACT FROM AUTHOR]

Introduction: Exposure to organochlorine compounds (OCs) may interfere with thyroid hormone (TH) homeostasis. The disruption of the deiodinase (DIO) enzymes has been proposed as a mechanism of action. Aim: To evaluate the association between exposure to OCs and TH status in pregnant women, as well as to explore the role of genetic variations in the DIO1 and DIO2 genes. Methods: The study population ( n = 1128) was composed of pregnant women who participated in the INMA Project (Spain, 2003–2006). Hexachlorobenzene (HCB), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (4,4´-DDE), b-hexachlorocyclohexane (b-HCH), polychlorobiphenyl (PCB) congeners 138, 153 and 180, thyroid stimulating hormone (TSH), total triiodothyronine (TT3) and free thyroxine (FT4) were measured in serum samples taken during the first trimester of pregnancy (mean [standard deviation (SD)]: 13.5 [2] weeks of gestation). Polymorphisms in DIO1 (rs2235544) and DIO2 (rs12885300) were genotyped in maternal DNA. Sociodemographic and dietary characteristics were obtained by questionnaire. Results: A 2-fold increase in HCB was associated with lower TT3 (% change = − 1.48; 95%CI: − 2.36, − 0.60). Women in the third tertile for b-HCH had lower TT3 (% change = − 3.19; 95%CI: − 5.64, − 0.67). The interactions between DIO1 rs2235544 and PCB153 and b-HCH were statistically significant. The inverse association between PCB153 and TT3 was the strongest among women with AA genotype. Women with CC genotype presented the strongest inverse association between b-HCH and FT4. Conclusion: Exposure to HCB and b-HCH was associated to a disruption in maternal TT3. The DIO1 rs2235544 SNP modified the association between exposure to some of the OCs (specifically b-HCH and PCB153) and maternal thyroid hormone levels. These results strengthen the hypothesis that DIO enzymes play a role in explaining the disruption of thyroid hormones in relation to exposure to OCs. [ABSTRACT FROM AUTHOR]