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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]

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]

We aimed to investigate the association of attention-deficit hyperactivity disorder (ADHD) symptoms and social competence outcomes with cognitive status in preschool children. The study population was drawn from three birth cohorts belonging to the Spanish INMA ( Infancia y Medio Ambiente) project: Menorca ( n = 289), Ribera d'Ebre ( n = 60), and Granada ( n = 108). Children were assessed at the age of 4 years for cognitive functions (McCarthy Scales of Children's Abilities, MSCA) by psychologists and for inattention and hyperactivity symptoms (ADHD Criteria of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, ADHD-DSM-IV) and social competence (California Preschool Social Competence Scale) by their teachers. Multiple regression analyses were conducted to examine potential associations between behavioral outcomes (ADHD symptoms and social competence) and MSCA cognitive outcomes, adjusting for confounders. The presence of general ADHD symptoms (inattention, hyperactivity, or both) and poorer social competence both showed negative associations with cognitive outcomes. When we compared children according to ADHD subtypes, those with inattention symptoms alone and those with both inattention and hyperactivity symptoms showed significantly lower cognitive function scores in comparison to children with no ADHD symptoms. Behavioral dysfunctions in preschoolers may be associated with impairment of cognitive functions. [ABSTRACT FROM AUTHOR]