Socioeconomic position, family context, and child cognitive development.

Socioeconomic position (SEP) may have different effects on cognitive development and family context could play a role in this association. This work aimed to analyse the role of socioeconomic positions, measured via various indicators collected longitudinally, in cognitive development at 7-11 years of age, evaluating the role of family context as a potential mediator. The study sample included 394 and 382 children from the INMA Gipuzkoa and Valencia cohorts, respectively. SEP indicators were assessed during pregnancy (family social class, parental education, employment, and disposable income) and at 7 (Gipuzkoa) and 11 (Valencia) years of age (At Risk of Poverty or Social Exclusion (AROPE)). Family context and cognitive development were measured with the Haezi-Etxadi Family Assessment Scale 7-11 (HEFAS 7-11) and Raven's Coloured Progressive Matrices (Raven's CPM), respectively. Linear regression models were developed to assess the relationships between (a) SEP-family context, (b) SEP-cognitive development, and (c) family context-cognitive development, adjusting for a priori-selected confounders. Simple and multiple mediation analyses were performed to explore the role of family context in the SEP-cognitive development relationship. Lower SEP was related with a lower cognitive score, this association being particularly robust for family social class. SEP indicators were related to subscales of family context, in particular those regarding cognitive stimulation, parental stress, and parenting. A relationship was also found between these three subscales and child cognitive development, mediating the effect of family social class on child cognition by 5.2, 5.5, and 10.8%, respectively, and 12.0% jointly.    Conclusion: Both family SEP and context contribute to a child's cognitive development. Equalising policies and positive parenting programmes could contribute to improving cognitive development in children. What is Known: • Parental social class, education, and employment status have been widely employed to measure socioeconomic position. What is New: • This work focuses on standard measurements of socioeconomic position but also other economic indicators such as the EHII and AROPE, and their effect on child cognitive development and family context. • Promotion of cognitive and linguistic development, parental stress and conflict, and parental profile fostering child development mediated the effect of family social class on cognitive development.

Poverty, social exclusion, and mental health: the role of the family context in children aged 7-11 years INMA mother-and-child cohort study.

Mental health problems are common in childhood and tend to be more frequent in populations at risk of poverty or social exclusion (AROPE). The family environment can play a role in reducing the impact of economic hardship on these problems. The aim of this study was to assess the effect of multidimensional poverty on the mental health of children aged 7-11 years and the role of the family environment in two areas of Spain. Participants were 395 and 382 children aged 7 and 11 from Gipuzkoa and Valencia, respectively. Internalizing and externalizing problem scales of the child behaviour checklist (CBCL) were used. AROPE indicators were obtained by questionnaire, and three dimensions of the family context (Organization of the Physical Environment and Social Context, Parental Stress and Conflict, and Parental Profile Fostering Development) were measured through subscales 3, 4 and 5 of the Haezi-Etxadi family assessment scale (7-11) (HEFAS 7-11), respectively. Data were analysed using negative binomial regression and Structural Equation Modelling. AROPE prevalence was 7.1 and 34.5% in Gipuzkoa and Valencia, respectively. In both cohorts, there was a significant increase in internalizing and externalizing problems among participants with a higher AROPE score. However, AROPE did not affect internalizing problems in children from families living in a better physical environment and with social support (Subscale 3). The AROPE effect was jointly mediated by subscales 4 and 5 in 42 and 62% of internalizing and externalizing problems, respectively. Preventing economic inequities by economic compensation policies, improving the neighbourhood and immediate environment around the school, and promoting positive parenting programmes can improve mental health in childhood.

Prenatal and postnatal exposure to acetaminophen in relation to autism spectrum and attention-deficit and hyperactivity symptoms in childhood: Meta-analysis in six European population-based cohorts.

The potential etiological role of early acetaminophen exposure on Autism Spectrum Conditions (ASC) and Attention-Deficit/Hyperactivity Disorder (ADHD) is inconclusive. We aimed to study this association in a collaborative study of six European population-based birth/child cohorts. A total of 73,881 mother-child pairs were included in the study. Prenatal and postnatal (up to 18 months) acetaminophen exposure was assessed through maternal questionnaires or interviews. ASC and ADHD symptoms were assessed at 4-12 years of age using validated instruments. Children were classified as having borderline/clinical symptoms using recommended cutoffs for each instrument. Hospital diagnoses were also available in one cohort. Analyses were adjusted for child and maternal characteristics along with indications for acetaminophen use. Adjusted cohort-specific effect estimates were combined using random-effects meta-analysis. The proportion of children having borderline/clinical symptoms ranged between 0.9 and 12.9% for ASC and between 1.2 and 12.2% for ADHD. Results indicated that children prenatally exposed to acetaminophen were 19% and 21% more likely to subsequently have borderline or clinical ASC (OR = 1.19, 95% CI 1.07-1.33) and ADHD symptoms (OR = 1.21, 95% CI 1.07-1.36) compared to non-exposed children. Boys and girls showed higher odds for ASC and ADHD symptoms after prenatal exposure, though these associations were slightly stronger among boys. Postnatal exposure to acetaminophen was not associated with ASC or ADHD symptoms. These results replicate previous work and support providing clear information to pregnant women and their partners about potential long-term risks of acetaminophen use.

Postnatal exposure to mercury and neuropsychological development among preschooler children.

The objective of this study was to describe the postnatal exposure to Hg and to evaluate its association with neuropsychological development among preschool children. The study population are 4-5 years old children (n = 1252) participant in the Spanish INMA Project. Total Hg was measured in cord blood and in hair samples taken at 4 years of age (2008-2012). Neuropsychological development was assessed using the McCarthy Scales of Children's Abilities (MSCA). Information on covariates and possible confounders was obtained by questionnaires during pregnancy and childhood. Generalized additive and linear regression models were built in order to assess the relationship between MSCA scores and Hg exposure. We also evaluated the magnitude of the possible bias generated from measurement error in seafood intake estimate from questionnaire and Hg determination. The geometric mean of hair Hg was 0.98 µg/g [95% confidence interval (CI) 0.94, 1.03]. In the regression analysis, the association between Hg and the MSCA scores was positive for all the scales and statistically significant for the verbal (ß = 0.89; 95%CI 0.38, 1.39), memory (ß = 0.42; 95%CI 0.09, 0.76) and general cognitive scales (ß = 1.35; 95%CI 0.45, 2.25). However, these associations were clearly attenuated when we adjusted by the children's fish intake variables or when took into account theoretical scenarios of low precision in fish intake and Hg measurements. Hg levels in this Spanish population were high in comparison with other European countries; however, we did not observe adverse effects on child neuropsychological development associated with this postnatal exposure to Hg.

Similarities and differences of dietary and other determinants of iodine status in pregnant women from three European birth cohorts.

PURPOSE: As a component of thyroid hormones, adequate iodine intake is essential during pregnancy for fetal neurodevelopment. Across Europe, iodine deficiency is common in pregnancy, but data are lacking on the predictors of iodine status at this life stage. We, therefore, aimed to explore determinants of iodine status during pregnancy in three European populations of differing iodine status. METHODS: Data were from 6566 pregnant women from three prospective population-based birth cohorts from the United Kingdom (ALSPAC, n = 2852), Spain (INMA, n = 1460), and The Netherlands (Generation R, n = 2254). Urinary iodine-to-creatinine ratio (UI/Creat, µg/g) was measured in spot-urine samples in pregnancy (≤ 18-weeks gestation). Maternal dietary intake, categorised by food groups (g/day), was estimated from food-frequency questionnaires (FFQs). Multivariable regression models used dietary variables (energy-adjusted) and maternal characteristics as predictors of iodine status. RESULTS: Median UI/Creat in pregnant women of ALSPAC, INMA, and Generation R was 121, 151, and 210 µg/g, respectively. Maternal age was positively associated with UI/Creat in all cohorts (P < 0.001), while UI/Creat varied by ethnicity only in Generation R (P < 0.05). Of the dietary predictors, intake of milk and dairy products (per 100 g/day) was positively associated with UI/Creat in all cohorts [ALSPAC (B = 3.73, P < 0.0001); INMA (B = 6.92, P = 0.002); Generation R (B = 2.34, P = 0.001)]. Cohort-specific dietary determinants positively associated with UI/Creat included fish and shellfish in ALSPAC and INMA, and eggs and cereal/cereal products in Generation R. CONCLUSIONS: The cohort-specific dietary determinants probably reflect not only dietary habits but iodine-fortification policies; hence, public-health interventions to improve iodine intake in pregnancy need to be country-specific.

Maternal selenium status and neuropsychological development in Spanish preschool children.

BACKGROUND: The relationship between maternal selenium (Se) status and child neurodevelopment has been scarcely assessed. In a previous study we observed an inverse U-shaped association between maternal Se concentrations and infant neurodevelopment at 12 months of age. In this study, this non-linear association was explored at preschool age. The effect modification by breastfeeding, child's sex and cord blood mercury was also evaluated. METHODS: Study subjects were 490 mother-child pairs from the Spanish Childhood and Environment Project (INMA, 2003-2012). Child neuropsychological development was assessed at around 5 years of age by the McCarthy Scales of Children's Abilities (MSCA). Sociodemographic and dietary characteristics were collected by questionnaire at the first and third trimester of gestation and at 5 years of age. Se was measured in serum samples by ICP-MS at the end of the first trimester of pregnancy (mean ±â€¯standard deviation (SD) = 12.4 ±â€¯0.6 weeks of gestation). RESULTS: The mean ±â€¯SD of maternal serum Se concentrations was 79.9 ±â€¯8.1 µg/L. In multivariate analysis, no linear association was found between Se concentrations and the nine MSCA scales. Generalized additive models indicated inverted U-shaped relationships between Se concentrations and the verbal and global memory scales. When assessing the influence of effect modifiers, breastfeeding played a role: the association between Se and neuropsychological development was inverted U-shaped for the quantitative, general cognitive, working memory, fine motor, global motor and executive function scales only for non-breastfed children. CONCLUSION: Low and high maternal Se concentrations seem to be harmful for child neuropsychological development, however further studies should explore this non-linear relationship.

Are Early Physical Activity and Sedentary Behaviors Related to Working Memory at 7 and 14 Years of Age?

OBJECTIVE: To evaluate the role of extracurricular physical activity and sedentary behavior at preschool and primary school age on working memory at primary school age and adolescence, respectively. STUDY DESIGN: This prospective study was based on a birth cohort across 4 Spanish regions. In the 3 younger subcohorts (n = 1093), parents reported lifestyle habits of child at age 4 years of age on a questionnaire, and children performed a computerized working memory task at 7 years of age. In the older subcohort (n = 307), the questionnaire was completed at 6 years of age and working memory was tested at 14 years of age. Adjusted regression models were developed to investigate the associations between lifestyle habits and working memory. RESULTS: Low extracurricular physical activity levels at 4 years of age were associated with a nonsignificant 0.95% (95% CI -2.81 to 0.92) reduction of correct responses in the working memory task at age 7 years of age. Low extracurricular physical activity levels at 6 years of age were associated with a 4.22% (95% CI -8.05 to -0.39) reduction of correct responses at age 14 years. Television watching was not associated with working memory. Other sedentary behaviors at 6 year of age were associated with a 5.07% (95% CI -9.68 to -0.46) reduction of correct responses in boys at 14 years of age. CONCLUSION: Low extracurricular physical activity levels at preschool and primary school ages were associated with poorer working memory performance at primary school age and adolescence, respectively. High sedentary behavior levels at primary school age were related negatively to working memory in adolescent boys.

Distributions and determinants of urinary biomarkers of organophosphate pesticide exposure in a prospective Spanish birth cohort study.

BACKGROUND: Prenatal exposure to organophosphate pesticides (OPs) has been associated with impaired child development. Pesticide exposure determinants need to be studied in order to identify sources and pathways of pesticide exposure. The aim of this paper is to describe prenatal exposure to OPs and evaluate the associated factors in pregnant women. METHODS: The study population consisted of pregnant women (n = 573) who participated in the INMA birth cohort study in Valencia (Spain, 2003-2006). OP metabolites were analyzed in maternal urine at the 32nd week of gestation using a liquid chromatography-high resolution mass spectrometry method. The analysis included non-specific (diethyl phosphate [DEP], diethyl thiophosphate [DETP], dimethyl thiophosphate [DMTP], dimethyl dithiophosphate [DMDTP]) and specific metabolites (2-diethylamino-6-methyl-4-pyrimidinol [DEAMPY], 2-isopropyl-4-methyl-6-hydroxypyrimidine [IMPY], para-nitrophenol [PNP], and 3,5,6-trichloro-2-pyridinol [TCPY]). Information about the sociodemographic, environmental, and dietary characteristics was obtained by questionnaire. The association between log-transformed OPs and covariates was analyzed using multivariable interval censored regression. RESULTS: The detection frequencies were low, DMTP and TCPY being the most frequently detected metabolites (53.8% and 39.1%, respectively). All the OP metabolites were positively associated with maternal intake of fruits and vegetables. Other maternal characteristics related to the OPs were body mass index (BMI) before pregnancy and smoking habit during pregnancy. Women with lower BMI and those who did not smoke presented higher OP concentrations. Moreover, mothers who had a yard or garden with plants at home or who lived in an urban area were also more exposed to OPs. CONCLUSIONS: The OP detection frequencies and the concentrations observed in our study population were low, compared with most of the previously published studies. Given the high vulnerability of the fetus to neurotoxicant exposure, further research on the determinants of the body burden of OPs during pregnancy would be necessary. The knowledge gained from such studies would enhance the effectiveness of public health control and future recommendations in order to reduce the risk to both the health of pregnant women and the health and development of their children.

[Exposure to noise at home, emotional behaviour, and attention deficit hyperactivity disorder in 9-year-old children].

BACKGROUND: The purpose of this study was to assess the relationship between noise disturbance at home, sleep disturbance, and neurodevelopmental problems in 9-year-old children. MATERIAL AND METHODS: Noise exposure (frequency) perceived by 430 9-year-old children from the INMA cohort in Valencia, Spain, were reported by their mothers. The risk of developing attention deficit hyperactivity disorder, as well as internalizing and externalizing problems, were assessed using the Child Behaviour Checklist. RESULTS: The risk of internalizing (18%) and externalizing problems (11.7%) was higher compared to the risk of developing attention deficit hyperactivity disorder (1.4%) and were more prevalent in boys than in girls. The most common and bothersome noise exposures were generated at home (50.8-55.3%) and by neighbours (24.5%). The risk of neurodevelopmental problems was associated with sleep disturbances, particularly in relation with attention deficit hyperactivity disorder (16.1 vs 4%; p<0.001), with no differences observed between sex. Sleep disturbances were significantly more common in children exposed to noise from household or neighbours. High levels of noise exposure from street traffic and neighbours were linked to an increased risk of attention deficit hyperactivity disorder, while noise from other children at home was associated with a higher risk of internalizing and externalizing problems. These effects remained consistent even after adjusting for sleep disturbances. CONCLUSIONS: High levels of noise annoyance from various sources perceived at home are differently associated with the risks of different neurodevelopmental problems in 9-year-old boys and girls, with sleep disturbances not influencing this relationship.

Residential green and blue spaces and working memory in children aged 6-12 years old. Results from the INMA cohort.

Availability of green and blue spaces in the area of residence has been related to various health outcomes during childhood, including neurodevelopment. Some studies have shown that children living in greener and/or bluer areas score better on cognitive tasks although the evidence is inconsistent. These protective effects are hypothesized to occur in part through reductions in air pollution exposure and odds of attention-deficit/hyperactivity disorder (ADHD). This study analysed the effects of residential green and blue spaces on working memory of children in the Spanish INfancia y Medio Ambiente (INMA) birth cohort and the potential joint mediating role of air pollution and ADHD. The study samples were composed of 1738 six-to eight-year-olds (M = 7.53, SD = 0.68, 49% female) and 1449 ten-to twelve-year-olds (M = 11.18, SD = 0.69, 50% female) living in Asturias, Gipuzkoa, Sabadell or Valencia, Spain. Individual Normalized Difference Vegetation Index (NDVI) values in 100-, 300- and 500-m buffers and availability of green and blue spaces >5000 m2 in 300-m buffers were calculated using Geographic Information Systems software. Individual NO2 values for the home environment were estimated using ESCAPE's land use regression models. ADHD diagnosis was reported by participants' parents via a questionnaire. Working memory was measured with numbers and colours (in the younger group only) N-back tests (2- and 3-back d'). Mixed-effects models informed of the beneficial effects of NDVI in a 300-m buffer on numerical working memory in the younger sample although the results were not consistent for all d' scores considered and failed to detect significant effects through the candidate mediators. Availability of major blue spaces did not predict working memory performance. Provision of green spaces may play a role in children's working memory but further research is required.

Social inequalities, green and blue spaces and mental health in 6-12 years old children participating in the INMA cohort.

Availability of green and blue spaces in the area of residence has been related to various health outcomes during childhood, including mental health. These environmental exposures are not evenly distributed among socioeconomic groups, which may increase social inequalities in mental health. The mechanisms through which natural environments may promote mental health are numerous and diverse. This study aimed to explore 1) the potential associations of socioeconomic variables (SES and maternal education attainment) with mental health scores and residential greenness, blueness and NO2 metrics, and, 2) the association between greenness and blueness metrics and mental health scores of children in the Spanish INfancia y Medio Ambiente (INMA) birth cohort at two different time points. The study samples were composed of 1738 six-to eight-year-olds (49% female) and 1449 ten-to twelve-year-olds (living in Asturias, Gipuzkoa, Sabadell and Valencia, Spain. Individual Normalized Difference Vegetation Index (NDVI) values in 100-, 300- and 500-m buffers and availability of green and blue spaces >5000 m2 in 300-m buffers were calculated using Geographic Information Systems software. Residential NO2 values were estimated using land use regression models. Internalizing, externalizing and total problems scores were obtained with the Strengths and Difficulties Questionnaire (SDQ). Linear and logistic mixed-effects models revealed unequal distribution of environmental exposures by SES and maternal education but did not show statistically significant associations between greenness and blueness metrics and mental health indicators. The protective effect of green and blue spaces on children's mental health could not be confirmed in this study and therefore further research is required.

Risk of child poverty and social exclusion in two Spanish regions: social and family determinants.

OBJECTIVE: Describe the risk of poverty and social exclusion in children aged 8-11 years from Gipuzkoa and Valencia (Spain), through AROPE (At Risk Of Poverty or Social Exclusion) indicators, and evaluate their associated factors in the INMA Project (Childhood and Environment). METHOD: Families in Gipuzkoa and Valencia (394 and 382, respectively) completed a questionnaire in 2015-2016. Low work intensity (LWI), at risk of poverty (RP) and material deprivation (MD) were estimated. AROPE consisted in meeting any of the previous sub-indicators. Socio-demographic, family and parental characteristics were considered. Frequencies, Venn's diagrams, and chi-square and Fisher tests were used in bivariate analysis and logistic regression in multivariate analysis. RESULTS: For LWI, RP, MD and AROPE, prevalence of 2.5%, 5.6%, 2.3% and 7.2% were obtained in Gipuzkoa, and 8.1%, 31.5%, 7.8% and 34.7% in Valencia, respectively. In the multivariate analysis, the AROPE was associated in both areas with maternal social class and non-nuclear families. In Gipuzkoa, it was also related to maternal education. In Valencia, other factors were the mother's foreign origin, and paternal education and smoking. CONCLUSION: There is higher AROPE prevalence in Valencia. Social class and family type were shared factors, but a differential pattern is observed in other social determinants. It is essential to implement social policies to reduce this axis of inequalities in health, especially in childhood.

Exposure to mercury among 9-year-old children and neurobehavioural function.

Mercury (Hg) is an environmental neurotoxicant whose main route of exposure in humans is the consumption of seafood. The aim of this study was to explore the relationship between Hg exposure at 9 years old and behaviour assessed at 9 and 11 years old. Study subjects were mother-child pairs participating in the INMA (Environment and Childhood) Project in Valencia (Spain). Total Hg (THg) was measured in hair samples from the children at 9 years old. Behaviour and emotions were assessed at 9 (n = 472) years and 11 (n = 385) years of age using the Child Behaviour Checklist test (CBCL) and the Conners Parents Rating Scale-Revised: Short Form (CPRS-R:S). Furthermore, the attention function was assessed by the Attention Network Test at 11 years old. Socio-demographic, lifestyle and dietary information was collected through questionnaires during pregnancy and childhood. Polymorphism in BDNF, APOE and GSTP1 were genotyped in cord blood DNA. Multivariable negative binomial regression models were built in order to study the association between THg concentrations and the scores obtained by the children at 9 and 11 years old. Effect modification by sex and genetic polymorphisms was assessed. The association between Hg levels and CBCL scores was positive (worse neurobehavioural development) for the CBCL internalizing and total problem scales (Incidence Rate Ratio [95% confidence interval] = 1.07 [1.01, 1.13] and 1.05 [0.99, 1.11], respectively). The association between Hg and the externalizing and total problems CBCL scales and the Attention Deficit Hyperactivity Disorder (ADHD) index of the CPRS-R:S was different according to sex, with boys obtaining worse scores with increasing Hg, compared to girls. Statistically significant interactions were also observed for genetic polymorphisms affecting the association between early exposure to Hg and both CBCL and CPRS-R:S scores. In conclusion, postnatal Hg exposure is associated with poorer neurobehavioural development in 9- and 11-year-old children. Sex and the presence of certain genetic polymorphisms modified this association.

The role of parental social class, education and unemployment on child cognitive development.

OBJECTIVE: Assessing the association between socioeconomic gradient and cognitive development among children of a Spanish birth cohort aged 5-6 years from a gender perspective. METHOD: Cognitive development was assessed on 525 children aged 5-6 years in the INMA-Valencia cohort, with the Global Cognitive Score (GCS) from McCarthy Scales of Children's Abilities. Information on social class, education level and employment was collected for both parents in addition to other sociodemographic factors, parental, family and child characteristics. The relationship between maternal and paternal socioeconomic gradient and cognitive development was assessed by linear regressions and comparing the variance explained by each indicator measured in the mother and father. RESULTS: Maternal socioeconomic gradient indicators explained more variance on GCS than paternal. Maternal education and paternal social class had an important individual effect that stayed after adjusting by other parental, child and family determinants. In the multivariable analysis, maternal education, age and intelligence, paternal social class and the child's age and sex were significantly associated with cognitive development. CONCLUSIONS: Diverse socioeconomic gradient factors have an important influence on cognitive development, maternal education being the strongest determinant. Policies should be implemented to mitigate the negative effects of this gradient on child development.

Maternal copper status and neuropsychological development in infants and preschool children.

INTRODUCTION: Copper (Cu) is an essential element involved in biological processes; however, excessive Cu could be harmful because of its reactive nature. Very few studies have evaluated its potential neurotoxic effects. We aimed to evaluate the association between maternal Cu levels and children's neuropsychological development. METHODS: Study subjects were mother-child pairs from the Spanish INMA (i.e. Childhood and Environment) Project. Cu was measured by inductively coupled plasma mass spectrometry in serum samples taken at the first trimester of pregnancy (2003-2005). Neuropsychological development was assessed using the Bayley Scales of Infant Development (BSID) at 12 months (n = 651) and the McCarthy Scales of Children's Abilities (MSCA) at 5 years of age (n = 490). Covariates were obtained by questionnaires during pregnancy and childhood. Multivariate linear and non-linear models were built in order to study the association between maternal Cu and child neuropsychological development. RESULTS: The mean ±â€¯standard deviation of maternal Cu concentrations was 1606 ±â€¯272 µg/L. In the multivariate analysis, a negative linear association was found between maternal Cu concentrations and both the BSID mental scale (beta = -0.051; 95% confidence intervals [CI]: -0.102, -0.001) and the MSCA verbal scale (beta = -0.044; 95%CI:-0.094, 0.006). Boys obtained poorer scores than girls, with increasing Cu at 12 months (interaction p-value = 0.040 for the mental scale and 0.074 for the psychomotor scale). This effect modification disappeared at 5 years of age. The association between Cu and the MSCA scores (verbal, perceptive performance, global memory and motor, general cognitive, and executive function scales) was negative for those children with lowest maternal iron concentrations (<938µg/L). CONCLUSION: The Cu concentrations observed in our study were within the reference range established for healthy pregnant women in previous studies. The results of this study contribute to the body of scientific knowledge with important information on the possible neurotoxic capability of Cu during pregnancy.

Maternal circulating Vitamin D3 levels during pregnancy and behaviour across childhood.

Vitamin D deficiency during critical periods of development could lead to persistent brain alterations. We aimed to assess the association between maternal vitamin D3, the major circulatory form of vitamin D, at pregnancy and neurodevelopmental outcomes during childhood, namely: behavioural problems, Attention Deficit and Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) symptoms, and social competence. This study included 2,107 mother-child pairs of a Spanish population-based birth cohort. Maternal plasma vitamin D3 was measured in pregnancy. The outcomes were measured through questionnaires at 5, 8, 14, and 18 years old. We ran multivariate regression models adjusted for potential confounding variables. We found that per each 10 ng/mL increment of maternal vitamin D3, children obtained higher social competence scores (coefficient = 0.77; 95% CI = 0.19, 1.35) at 5 years old. However, we observed null associations between maternal vitamin D3 and total behavioural problems and ADHD and ASD symptoms in children from 5 to 18 years old. Further studies carried out in countries where the population is exposed to lower vitamin D levels are needed.

Iodine intake from supplements and diet during pregnancy and child cognitive and motor development: the INMA Mother and Child Cohort Study.

BACKGROUND: The effect of mild-to-moderate maternal iodine deficiency on the neuropsychological development of their offspring is uncertain. We aimed to assess the association between iodine status during pregnancy and the cognitive and motor development of children at 4-5 years. METHODS: We conducted a prospective cohort study in four Spanish regions with recruitment of pregnant women between 2003 and 2008 and follow-up of their children up to 4-5 years (mean (SD)=4.8 (0.6)). Cognitive and motor function was assessed in 1803 children using the McCarthy Scales of Children's Abilities. Dietary iodine and supplementation were measured through questionnaires twice during pregnancy. Urinary iodine concentration (UIC) was measured in spot samples. The residuals of a regression of UIC against creatinine were used to define a variable corrected for creatinine (UIC~Cr). RESULTS: Neither iodine supplements nor iodised salt consumption or maternal UIC were associated with cognitive or motor function. After adjusting for creatinine, children of women with UIC~Cr <100 µg/L had 3.93 (95% CI -6.18 to -1.69) general cognitive scores lower than the reference (150-249 µg/L). Dietary iodine was inversely associated with motor scores and milk but not other dairy products or seafood consumption accounted for this association (beta: -1.36; 95% CI -2.12 to -0.61; per one daily milk serving). CONCLUSIONS: We found an association between low maternal urinary iodine and lower cognitive scores in childhood, although only when corrected for creatinine, adding to the evidence that iodine deficiency may have potential harmful effects on neurodevelopment. Iodine supplementation does not appear to improve child's neurodevelopment at 4-5 years.

Selenium status during pregnancy: Influential factors and effects on neuropsychological development among Spanish infants.

Selenium (Se) has been positively associated with neurodevelopment in early life. However, its margin of safety is rather narrow, and few prospective studies have evaluated its potential neurotoxic effects at intermediate levels. We aimed to explore the association between maternal Se concentrations and child neuropsychological development, including the genetic effect modification of the Se metabolizing gene INMT. Study subjects were 650 mother-child pairs from the Spanish Childhood and Environment Project (INMA, 2003-2005). Infant neuropsychological development was assessed around 12months of age by the Bayley Scales of Infant Development. Sociodemographic and dietary characteristics were collected by questionnaire at the first and third trimester of gestation. Se was measured in serum samples at the first trimester. The mean serum Se concentration was 79.7 (standard deviation=7.9) µg/L. In multivariate analysis, nonsignificant inverse linear associations were found between Se concentrations and standardized mental and psychomotor development scores (ß (95% CI)=-0.13 (-0.29, 0.03) and ß (95% CI)=-0.08 (-0.24, 0.07), respectively). Generalized additive models indicated inverted U-shaped relationships between Se concentrations and both scales. Using segmented regression, the turning point for the associations was estimated at 86µg/L for both scales. The association between Se and neuropsychological development was inverted U-shaped for children with the AG+AA genotype for rs6970396 INMT but a descending curve was suggested for the GG genotype. Further studies would be necessary in order to disentangle the complex equilibrium between the toxicity and benefits of Se exposure during the prenatal period.

Sleeping, TV, Cognitively Stimulating Activities, Physical Activity, and Attention-Deficit Hyperactivity Disorder Symptom Incidence in Children: A Prospective Study.

OBJECTIVE: To analyze associations between time spent sleeping, watching TV, engaging in cognitively stimulating activities, and engaging in physical activity, all at 4 years, and (1) attention-deficit/hyperactivity disorder (ADHD) symptoms and (2) behavior problems, both assessed at 7 years, in ADHD-free children at baseline. METHOD: In total, 817 participants of the Infancia y Medio Ambiente birth cohort, without ADHD at baseline, were included. At the 4-year follow-up, parents reported the time that their children spent sleeping, watching TV, engaging in cognitively stimulating activities, and engaging in physical activity. At the 7-year follow-up, parents completed the Conners' Parent Rating Scales and the Strengths and Difficulties Questionnaire, which measure ADHD symptoms and behavior problems, respectively. Negative binomial regression models were used to assess associations between the activities at 4 years and ADHD symptoms and behavior problems at 7 years. RESULTS: Children (48% girls) spent a median (p25-p75) of 10 (10-11) hours per day sleeping, 1.5 (0.9-2) hours per day watching TV, 1.4 (0.9-1.9) hours per day engaging in cognitively stimulating activities, and 1.5 (0.4-2.3) hours per day engaging in physical activity. Longer sleep duration (>10 hours per day) was associated with a lower ADHD symptom score (adjusted incidence rate ratio = 0.97, 95% confidence interval, 0.95-1.00). Longer time spent in cognitively stimulating activities (>1 hours per day) was associated with lower scores of both ADHD symptoms (0.96, 0.94-0.98) and behavior problems (0.89, 0.83-0.97). Time spent watching TV and engaging in physical activity were not associated with either outcomes. CONCLUSION: A shorter sleep duration and less time spent in cognitively stimulating activities were associated with an increased risk of developing ADHD symptoms and behavior problems.