Effect of birth weight, maternal education and prenatal smoking on offspring intelligence at school age

Early cognitive development and psychopathology in children at familial high risk for schizophrenia

Schizophrenia is a neurodevelopmental disorder associated with deficits in cognitive development and childhood psychopathology. Previous studies have focused on older children and the few studies of early childhood have yielded inconsistent findings. We studied cognitive development and psychopathology in children at familial high risk (FHR) of schizophrenia and matched controls from 1 to 6 years and hypothesized that FHR children would show consistent deficits across cognitive and behavioral measures in early childhood.

STUDY DESIGN

Cognitive development in children at high familial risk for schizophrenia or schizoaffective disorder (n = 33) and matched healthy controls (n = 66) was assessed at 1 and 2 years with the Mullen Scales of Early Learning, and at 4 and 6 years with the Stanford Binet Intelligence Scales, BRIEF-P/BRIEF and CANTAB. Psychopathology was assessed at 4 and 6 years with the BASC-2. General linear models were used to examine differences on outcome scores, and chi-square analyses were used to explore differences in the proportion of "at risk" or "below average" score profiles.

STUDY RESULTS

FHR children scored significantly lower than controls on Mullen Composite at age 2, and demonstrated broad deficits in IQ, executive function and working memory and 4 and 6 years. FHR children were also rated as significantly worse on most items of the BASC-2 at ages 4 and 6.

CONCLUSIONS

Children at FHR for schizophrenia demonstrate abnormal cognitive development and psychopathology at younger ages than previously detected, suggesting that early detection and intervention needs to be targeted to very early childhood.

How are they doing? The academic performance and mental wellbeing of world cup babies

In June 2002, South Korea cohosted the 17th FIFA World Cup. Unexpected wins carried the Korean National Football Team to the semi-finals and sparked an unprecedented euphoria among Koreans. Die-hard fans and occasional football viewers, young and old, women and men flocked the streets side by side, cheered for their team, and partied through the nights. In the subsequent spring of 2003, the country experienced a temporary and significant increase in its fertility rate. Using a difference-in-differences design, we exploit the quasi-experimental nature of this episode to investigate the Beckerian trade-off between the quantity and quality of children born to parents in South Korea. Our results support the notion of an adverse effect on child quality. Students born approximately ten months after the World Cup tend to perform significantly worse in school. Moreover, our results uncover a hitherto overlooked aspect: the same students exhibit significantly higher degrees of mental wellbeing.

Maternal smoking during pregnancy and intelligence quotient of offspring aged 18 and 30 years: Evidence from two birth cohorts in southern Brazil

Maternal smoking during pregnancy causes several harmful effects, including deficits in the intelligence quotient (IQ), a measure associated with academic achievements and higher socioeconomic position. We aimed to measure the association between maternal smoking during pregnancy and offspring's IQ in two birth cohorts from Pelotas, Brazil. Data from the 1982 and 1993 birth cohorts were analyzed. Smoking during pregnancy was ascertained at the perinatal follow-up, and IQ was measured at 30 years (1982) and 18 years (1993). Simple and multiple linear regressions were used for crude and adjusted analysis. Mediation analysis was performed using birth weight and breastfeeding as possible mediators. Data analysis was conducted in 2020. There were 3611 and 4050 participants from the 1982 and 1993 cohorts, respectively. After adjustment for potential confounders, the inverse association between smoking during pregnancy and children's IQ remained significant in both cohorts. Offspring of mothers who smoked during pregnancy had an average of 1.32 less IQ points (95%CI: -2.23, -0.242) in the 1982 cohort, and an average of 1.66 less IQ points (95%CI: -2.42, -0.90) in the 1993 cohort. Neither cohort showed association with paternal smoking (negative controls) after adjustment. Breastfeeding's mediated effects accounted for 26.2% and 23.9% of the association in the 1982 and 1993 cohorts, respectively, while birth weight's accounted for 6.8% and 30.1%, respectively; indirect effects were not significant. The inverse association between maternal smoking and IQ and the lack of association with paternal smoking reinforces our findings of a negative association between exposure and outcome.

Association of Very Preterm Birth or Very Low Birth Weight With Intelligence in Adulthood: An Individual Participant Data Meta-analysis

IMPORTANCE

Birth before 32 weeks' gestation (very preterm [VPT]) and birth weight below 1500 g (very low birth weight [VLBW]) have been associated with lower cognitive performance in childhood. However, there are few investigations of the association of neonatal morbidities and maternal educational levels with the adult cognitive performance of individuals born VPT or VLBW (VPT/VLBW).

OBJECTIVE

To assess differences in adult IQ between VPT/VLBW and term-born individuals and to examine the association of adult IQ with cohort factors, neonatal morbidities, and maternal educational level among VPT/VLBW participants.

DATA SOURCES

Systematic review of published data from PubMed and meta-analysis of individual participant data (IPD) of cohorts from 2 consortia (Research on European Children and Adults Born Preterm [RECAP] and Adults Born Preterm International Collaboration [APIC]).

STUDY SELECTION

The meta-analysis included prospective longitudinal cohort studies that assessed the full-scale IQ of adults born VPT or VLBW and respective control groups comprising term-born adults.

DATA EXTRACTION AND SYNTHESIS

The study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline for analyses of individual participant data and identified 8 studies that provided data from 2135 adults (1068 VPT/VLBW and 1067 term-born participants) born between 1978 and 1995. Meta-analyses of IPD were performed using a 1-stage approach, treating VPT birth or VLBW and cohort as random effects.

MAIN OUTCOMES AND MEASURES

Full-scale IQ scores were converted to z scores within each cohort using the combined SD of VPT/VLBW participants and a control group of term-born participants, with scores centered on the mean of the control group.

RESULTS

A total of 426 records were identified and screened. After exclusions, 13 studies were included in the aggregate meta-analysis. The IPD meta-analysis included 8 of the 9 RECAP and APIC cohorts with adult IQ data. The mean (SD) age among the 8 IPD cohorts was 24.6 (4.3) years, and 1163 participants (54.5%) were women. In unadjusted analyses, VPT/VLBW participants had mean adult IQ scores that were 0.78 SD (95% CI, -0.90 to -0.66 SD) lower than term-born participants, equivalent to a difference of 12 IQ points. Among VPT/VLBW participants, lower gestational age (score difference per week of gestation, 0.11; 95% CI, 0.07-0.14), lower birth weight z scores (score difference per 1.0 SD, 0.21; 95% CI, 0.14-0.28), the presence of neonatal bronchopulmonary dysplasia (score difference, -0.16; 95% CI, -0.30 to -0.02) or any grade of intraventricular hemorrhage (score difference, -0.19; 95% CI, -0.33 to -0.05), and lower maternal educational level (score difference, 0.26; 95% CI, 0.17-0.35) were all significantly associated with lower IQ scores in adulthood.

CONCLUSIONS AND RELEVANCE

In this IPD meta-analysis, lower gestational age, lower weight for gestational age, neonatal morbidities, and lower maternal educational levels were all important risk factors associated with lower IQ among young adults born VPT or VLBW.

Effects of accumulated environmental, social and host exposures on early childhood educational outcomes

BACKGROUND

Persistent disparities in academic performance may result from a confluence of adverse exposures accruing disproportionately to specific subpopulations.

OBJECTIVE

Our overarching objective was to investigate how multiple exposures experienced over time affect early childhood educational outcomes. We were specifically interested in whether there were: racial/ethnic disparities in prevalence of adverse exposures; racial/ethnic disparities in associations observed between adverse exposures and early childhood educational outcomes; and interactions between exposures, suggesting that one exposure augments susceptibility to adverse effects of another exposure.

METHODS

We link geocoded North Carolina birth data for non-Hispanic white (NHW) and non-Hispanic black (NHB) children to blood lead surveillance data and 4th grade end-of-grade (EOG) standardized test scores (n = 65,151). We construct a local, spatial index of racial isolation (RI) of NHB at the block group level. We fit race-stratified multi-level models of reading and mathematics EOG scores regressed on birthweight percentile for gestational age, blood lead level, maternal smoking, economic disadvantage, and RI, adjusting for maternal- and child-level covariates and median household income.

RESULTS

There were marked racial/ethnic disparities in prevalence of adverse exposures. Specifically, NHB children were more likely than NHW children to be economically disadvantaged (80% vs. 40%), live in block groups with the highest quintile of RI (46% vs. 5%), have higher blood lead levels (4.6 vs. 3.7 μg/dL), and lower birthweight percentile for gestational age (mean: 39th percentile vs. 51st percentile). NHB children were less likely to have mothers who reported smoking during pregnancy (11% and 22%). We observed associations between key adverse exposures and reading and math EOG scores in 4th grade. Higher birthweight percentile for gestational age was associated with higher EOG scores, while economic disadvantage, maternal smoking, and elevated blood lead levels were associated with lower EOG scores. Associations observed for NHB and NHW children were generally not statistically different from one another, with the exception of neighborhood RI. NHB children residing in block groups in the highest RI quintile had reading and math scores 1.54 (0.74, 2.34) and 1.12 (0.38, 1.87) points lower, respectively, compared to those in the lowest RI quintile; statistically significant decrements in EOG scores associated with RI were not observed for NHW children. We did not find evidence of multiplicative interactions between exposures for NHB or NHW children.

DISCUSSION

Key adverse host, environmental, and social exposures accrue disproportionately to NHB children. Decrements in test scores associated with key adverse exposures were often but not always larger for NHB children, but were not significantly different from those estimated for NHW children. While we did not observe interactive effects, NHB children on average experience more deleterious combined exposures, resulting in larger decrements to test scores compared to NHW children.

Helping Clinicians to Detect ODD in Children with ADHD in Clinical Settings

The objectives of this study were to provide a basic tool for pediatricians or other physicians to suspect and detect ODD in children with ADHD and to distinguish the symptomatic profile of ODD from ADHD. 101 subjects with ADHD, 83 with both ADHD and ODD and 342 controls aged 8 to 15 years were included in the study. A semi-structured interview was performed for evaluation of psychiatric diagnoses. Both parents and teachers completed DSM-IV Disruptive Behavior Disorders Rating Scale. We found differences among all three diagnostic subsamples in two-by-two analyses for all dimensions (Inattention, Hyperactivity/Impulsivity and ODD) both according to parent and teacher reports (p < 0.03 for all analyses). Based on parental ODD scores, ROC Curve analyses between 'only ADHD' and 'ADHD+ODD' groups showed that AUC was equal 0.80 (95%CI = 0.73-0.86) and the best cutoff point for ODD diagnosis in the ADHD subjects was 0.68. This study demonstrates the presence of a basic tool for detection and suspicion of ODD in children with ADHD for primary care clinicians or pediatricians in clinical settings. Findings also indicate that patients with ODD and ADHD have more severe inattention, hyperactivity/impulsivity and oppositional symptoms than those with only ADHD have.

Maternal smoking during pregnancy and intelligence quotient in offspring: A systematic review and meta-analysis

BACKGROUND

Exposure to tobacco during pregnancy may disrupt fetal brain development and impact offspring cognitive development.

AIMS

To perform a systematic review and meta-analysis on maternal smoking during pregnancy and intelligence quotient (IQ) in childhood, adolescence, and adulthood.

METHODS

We searched PubMed, Lilacs, PsycINFO, and Web of Science. Original articles evaluating tobacco use/exposure during pregnancy and the offspring's IQ as the outcome. The review protocol is registered in PROSPERO (number CRD 42,019,116,257). For the meta-analysis, we included studies with information on the regression coefficient and its confidence interval (CI) or standard error. Random effects model was used for pooling the estimates.

RESULTS

25 studies were included in the review, and of these 14 met the inclusion criteria for the meta-analysis. The overall pooled estimate showed that subjects who were exposed to maternal smoking during pregnancy presented lower IQ scores, compared to those not exposed to maternal smoking (β -1.30; 95 % CI -1.74, -0.86; I² = 87.8 %); IQ scores were also lower in crude (β -5.46; 95 % CI -7.31, -3.60; I²: 79.0 %) and adjusted pooled estimates (β =-0.45; 95 % CI -0.76, -0.13; I² = 80.4 %), for the group exposed to maternal smoking. In the stratified analysis, an inverse association was also observed in studies with large sample size (n≥1000 participants) (β=-0.49; 95 % CI -0.96, -0.02), among those performed with adolescents (β=-1.16; 95 % CI -2.18, -0.14), and among those adjusted for maternal education (β=-0.57; 95 % CI -1.05, -0.08).

CONCLUSIONS

Our findings suggest that exposure to tobacco during pregnancy may have negative effects on IQ. However, the findings of this meta-analysis should be interpreted with caution.

A systematic literature review of epidemiologic studies of developmental manganese exposure and neurodevelopmental outcomes

BACKGROUND

Neurotoxic effects of high-level occupational exposure to manganese (Mn) are well established; however, whether lower-level environmental exposure to Mn in early life causes neurodevelopmental toxicity in children is unclear.

METHODS

A systematic literature review was conducted to identify and evaluate epidemiologic studies of specific Mn biomarkers assessed during gestation, childhood, or adolescence in association with neurodevelopmental outcomes, focusing on quantitative exposure-response estimates with specific endpoints that were assessed in multiple independent study populations. Study quality was evaluated using the revised RTI item bank and the Cochrane Risk of Bias tool, and the overall weight of epidemiologic evidence for causality was evaluated according to the Bradford Hill considerations.

RESULTS

Twenty-two epidemiologic studies were identified that estimated associations between early-life Mn biomarkers and neurodevelopmental outcomes. Seven of these studies provided adjusted estimates for the association with child intelligence assessed using versions of the Wechsler Intelligence Scales for Children; no other specific neurodevelopmental endpoints were assessed in more than three independent study populations each. Among the studies of child intelligence, five studies in four independent populations measured blood Mn, three studies measured hair Mn, and one measured dentin Mn. Overall, cross-sectional associations between Mn biomarkers and measures of child intelligence were mostly statistically nonsignificant but in a negative direction; however, the lone prospective cohort study found mostly null results, with some positive (favorable) associations between dentin Mn and child intelligence. Studies were methodologically limited by their cross-sectional design and potential for confounding and selection bias, as well as unaddressed questions on exposure assessment validity and biological plausibility.

CONCLUSIONS

The statistical associations reported in the few studies of specific Mn biomarkers and specific neurodevelopmental endpoints do not establish causal effects based on the Bradford Hill considerations. Additional prospective cohort studies of Mn biomarkers and validated neurodevelopmental outcomes, and a better understanding of the etiologic relevance of Mn biomarkers, are needed to shed light on whether environmental exposure to Mn causes adverse neurodevelopmental effects in children.

A multifactorial approach of nutritional, intellectual, brain development, cardiovascular risk, socio-economic, demographic and educational variables affecting the scholastic achievement in Chilean students: An eight- year follow-up study

The aim of this study was to quantitate the relative impact of nutritional, intellectual, brain development, cardiovascular risk, socio-economic, demographic and educational variables on the results of the 2009 Quality Education Measurement System (SIMCE) tests of language and mathematics for scholastic achievement (SA) applying a multifactorial approach, in school-age children of the 2010 5th elementary school grade (5ESG) and of the 1st grade of high school (1HSG). The purposes were: i) to test the hypothesis that intellectual ability, the level of SA of the educational establishments in the 2009 SIMCE tests, sex, parental schooling levels, and head circumference-for-age Z-score are the most relevant parameters associated with 2009 SIMCE outcomes; ii) to determine the predictive ability of the 2009 SIMCE results in determining the 2013 SIMCE outcomes for the 2010 5ESG cohort (when they graduated from elementary school, 8th grade) and for determining the 2013 University Selection Test (PSU) outcomes for the 2010 1HSG group (for university admission, when they graduated from high school, 4th grade); iii) to determine the association between the 2009 SIMCE results with the 2017 PSU outcomes for the 2010 5ESG group (for university admission, when they graduated from high school, 4th grade). A representative, proportional and stratified sample of 33 schools of the Metropolitan Region of Chile was randomly chosen. In these schools, 1,353 school-age children of both sexes, of the 2010 5ESG (n = 682; mean age = 10.8 years, SD = 0.6) and of the 2010 1HSG (n = 671; mean age = 14.8 years, SD = 0.6) participated. In both grades and tests, the findings confirm the hypotheses formulated. 2009 SIMCE outcomes were positively and significantly associated with 2013 SIMCE and with 2017 PSU and, with 2013 PSU outcomes in school-age children from 2010 5ESG and 1HSG, respectively. These findings may be useful for educational and health planning in Chile and countries in a comparable stage of development.

The effect of prenatal smoke exposure on child neuropsychological function: a prospective mother-child cohort study

Objective: To study prospectively the effect of prenatal smoke exposure (PSE) on child neuropsychological function and intelligence quotient (IQ).Background: PSE has been associated with adverse effects on child neurodevelopment. However, some studies reported that these associations disappear after adjustment for potential confounders.Methods: A cohortof 248 mothers-child dyad was followed from the first trimester of pregnancy until children were 7.5 years old. PSE was recorded during pregnancy by questionnaire and plasma cotinine. The Wechsler Intelligence Scale for Children, the Neuropsychological Assessment of Executive Functions for Children (ENFEN) and the School Neuropsychological Maturity Questionnaire were administered at 7.5 years of age. The effect of PSE on child IQ and neuropsychological function was assessed with ANCOVA, adjusting for obstetric, neonatal and sociodemographic factors.Results: Children whose mothers smoked throughout pregnancy scored lower in interference (ENFEN) compared to unexposed children (F = 4.1; p = .008). The results showed no differences in other executive functions, verbal and visual memory and IQ between the PSE groups.Conclusion: PSE had little effect on child neuropsychological outcome and was limited to mental flexibility. Nevertheless, these findings support further efforts aimed at encouraging mothers to quit smoking in pregnancy.

A gradient relationship between low birth weight and IQ: A meta-analysis

Multiple studies have reported that individuals with low birth weights (LBW, <2500 g) have a lower intelligence quotient (IQ) than those with normal birth weights (NBW, ≥2500 g). Based on 57 eligible individual studies including 12,137 participants, we performed a meta-analysis to estimate the association between low birth weight and individuals' IQ scores (IQs). The pooled weight mean difference (WMD) in IQs between NBW and LBW individuals was 10 (95% CI 9.26-11.68). The WMD was stable regardless of age. No publication bias was detected. The mean IQs of the extremely low birth weight (ELBW, <1000 g), very low birth weight (VLBW, 1000-1499 g), moderately low birth weight (MLBW, 1500-2499 g) and NBW individuals were 91, 94, 99 and 104, respectively. Additionally, the WMD in IQs with NBW were 14, 10 and 7 for ELBW, VLBW, and MLBW individuals, respectively. Two studies permitted estimates of the influence of social determinants of health to the discrepancy in IQs, which was 13%. Since IQ is inherited and influenced by environmental factors, parental IQs and other factors contribute to residual confounding of the results. As the conclusion was based on population studies, it may not be applicable to a single individual.

Long-term Cognitive Implications of Intrauterine Hyperglycemia in Adolescent Offspring of Women With Type 1 Diabetes (the EPICOM Study)

OBJECTIVE

Exposure to maternal diabetes in utero may have a negative impact on the developing brain. The objective was to examine long-term cognitive consequences of intrauterine hyperglycemia in adolescent offspring of women with type 1 diabetes and to ascertain a possible association with maternal HbA1c.

RESEARCH DESIGN AND METHODS

Offspring of a prospectively followed cohort of women with type 1 diabetes (n = 277) participated in a follow-up examination at the age of 13-19 years. A control group from the background population was identified (n = 301). Cognitive function was evaluated using Reynolds Intellectual Assessment Scales and classified into indices of composite intelligence, verbal and nonverbal intelligence, and composite memory. Frequencies of reading and writing problems and attendance to classes for children with learning difficulties were assessed.

RESULTS

Offspring of women with type 1 diabetes scored lower in all normalized and standardized intelligence indices compared with controls: composite intelligence (95.7 vs. 100, P = 0.001), verbal intelligence (96.2 vs. 100, P = 0.004), nonverbal intelligence (96.4 vs. 100, P = 0.008), and composite memory (95.7 vs. 100, P = 0.001). A higher frequency of diabetes-exposed offspring had parent-reported learning difficulties in primary school. Differences between groups remained after adjustment for confounders and potential mediators. We found no direct association between maternal HbA1c and offspring cognitive function in the exposed group.

CONCLUSIONS

Adolescent offspring of women with type 1 diabetes had lower cognitive function compared with a control group, also after adjustment for confounders and potential mediators. These differences may reflect direct harmful effects of maternal diabetes on neurodevelopment in the offspring.

Association between prenatal and current exposure to selected LCPUFAs and school performance at age 7

INTRODUCTION

Long-chain polyunsaturated fatty acids (LCPUFAs) are important for brain functioning and might, thus, influence cognition and school performance. However, research investigating LCPUFAs relationships with school performance is limited. The objective of this study was to determine the association between levels of the LCPUFAs docosahexaenoic acid (DHA), arachidonic acid (AA), eicosapentaenoic acid (EPA) and n-6 docosapentaenoic acid (Osbond acid, ObA) at study entry, 22 weeks of pregnancy, 32 weeks of pregnancy, at partus, in umbilical cord plasma and child's plasma at age 7 and school performance scores at age 7.

METHODS

Data from the Maastricht Essential Fatty Acid Birth cohort (MEFAB) were used for this study. Fatty acid levels of plasma phospholipids were measured in maternal blood plasma at study entry, 22 weeks of pregnancy, 32 weeks of pregnancy and partus. Childs fatty acid levels of plasma phospholipids were measured a in umbilical cord blood plasma, and in blood plasma of the child at age 7. Scores on national standardised tests for spelling, reading and arithmetic at age 7 were obtained via the school (scores were available for 149, 159 and 155 children, respectively). Associations between LCPUFA levels and school performance scores were analysed with categorical regression analyses with correction for covariates (smoking, maternal education, sex, breastfeeding, maternal intelligence, birth weight and BMI at age 7).

RESULTS

Significant (p<0.001) associations between DHA level at age 7 and both reading (β=0.158) and spelling (β=0.146) were found. Consistent significant negative associations were observed between all maternal DHA plasma levels and arithmetic scores at age 7 (all p<0.001, all β<-0.019). Additional significant negative associations were observed between maternal LCPUFA plasma levels at study entry and both reading and spelling scores at age 7; these associations were less consistent.

CONCLUSION

Plasma DHA levels at age 7 were positively associated with reading and spelling scores at age 7. Consistent significant negative associations between maternal plasma DHA levels and arithmetic scores of the child at age 7 were found. Although this is an observational study, which cannot proof causality, the consistent negative associations observed between maternal plasma DHA levels and the arithmetic scores of the children at age 7 calls upon prudence when considering DHA supplementation during pregnancy.

Prenatal smoking and childhood behavior problems: is the association mediated by birth weight?

Maternal smoking during pregnancy is associated with both reduced birth weight and adverse neurobehavioral outcomes. The aim of this study was to investigate longitudinal associations between maternal smoking during pregnancy and childhood behavioral outcomes, and to determine the role of birth weight in mediating such associations. The study included 489 mother-child pairs. Prenatal exposures were assessed via maternal interviews conducted on average 1 year after delivery and child behavior assessments were completed at 5-12 years of age using the Child Behavior Checklist (CBCL) and Teacher Report Form (TRF). Maternal smoking during pregnancy was associated with externalizing and total behavior problems according to both mother and teacher report. Maternal smoking was also associated with the following percentage increases in scores: 41% (CBCL) and 44% (TRF) for aggressive behavior and 65% (CBCL) and 47% (TRF) for attention problems. Associations with behavior problems were attenuated or no longer observed for mothers that quit smoking in early pregnancy. The proportion of the total effect of maternal smoking on behavioral outcomes explained by differences in birth weight was small and ranged from 6.6% for externalizing behavior on the CBCL to 20.1% for rule-breaking behavior on the CBCL. Our results suggest that birth weight differences explain only a small proportion of the magnitude of association between maternal smoking during pregnancy and selected behavioral outcomes.

Motor development related to duration of exclusive breastfeeding, B vitamin status and B12 supplementation in infants with a birth weight between 2000-3000 g, results from a randomized intervention trial

Background

Exclusive breastfeeding for 6 months is assumed to ensure adequate micronutrients for term infants. Our objective was to investigate the effects of prolonged breastfeeding on B vitamin status and neurodevelopment in 80 infants with subnormal birth weights (2000-3000 g) and examine if cobalamin supplementation may benefit motor function in infants who developed biochemical signs of impaired cobalamin function (total homocysteine (tHcy) > 6.5 μmol/L) at 6 months.

Methods

Levels of cobalamin, folate, riboflavin and pyridoxal 5´-phosphate, and the metabolic markers tHcy and methylmalonic acid (MMA), were determined at 6 weeks, 4 and 6 months (n = 80/68/66). Neurodevelopment was assessed with the Alberta Infants Motor Scale (AIMS) and the parental questionnaire Ages and Stages (ASQ) at 6 months.

At 6 months, 32 of 36 infants with tHcy > 6.5 μmol/L were enrolled in a double blind randomized controlled trial to receive 400 μg hydroxycobalamin intramuscularly (n = 16) or sham injection (n = 16). Biochemical status and neurodevelopment were evaluated after one month.

Results

Except for folate, infants who were exclusively breastfed for >1 month had lower B vitamin levels at all assessments and higher tHcy and MMA levels at 4 and 6 months. At 6 months, these infants had lower AIMS scores (p = 0.03) and ASQ gross motor scores (p = 0.01).

Compared to the placebo group, cobalamin treatment resulted in a decrease in plasma tHcy (p < 0.001) and MMA (p = 0.001) levels and a larger increase in AIMS (p = 0.02) and ASQ gross motor scores (p = 0.03).

Conclusions

The findings suggest that prolonged exclusive breastfeeding may not provide sufficient B vitamins for small infants, and that this may have a negative effect on early gross motor development. In infants with mild cobalamin deficiency at 6 months, cobalamin treatment significantly improvement cobalamin status and motor function, suggesting that the observed impairment in motor function associated with long-term exclusive breastfeeding, may be due to cobalamin deficiency.

Clinical trial registration

ClinicalTrials.gov, number NCT01201005

Prenatal and neonatal risk factors associated with children's developmental status at ages 4-7: lessons from the Jiangsu China birth defects prevention cohort

BACKGROUND

There is limited information involving population data about the role of maternal health, fetal growth and neonatal health on children's developmental status at ages 4-7 years. Our aim was to determine the contribution of maternal, fetal and neonatal health to developmental status at ages 4-7 years.

METHODS

In this 7-year follow-up prospective cohort study, a sample of 26,803 mothers participated in the beginning. Among their children, 19,187 voluntarily completed the development screening test or the social life ability survey, which were designed for two different age groups (<6 or ≥ 6 years old, respectively). Logistic regression analysis was used to link the data with the prenatal outcome card and interview questionnaire applied to pregnant women in previous study, to the analysis of various related factors such as demographic, socio-economic, disease and menstrual history, marriage and pregnancy care.

RESULT

Univariate and multivariate logistic regression analysis were used separately in two age groups [4-6 (n = 8439) and 6-7 (n = 10,748) years old] to analyse relative factors. Maternal age of 25-30 years, maternal education of high school and greater, family income and not drinking during pregnancy were associated with higher scores in development.

CONCLUSION

Both preconception and pregnancy health education and health care are the important maternal factors closely associated with children's cognitive and social competence. Public health policies for preconception care and public welfare for high-quality childcare are essential for improving children's life.

Polymorphic variation in the epigenetic gene DNMT3B modulates the environmental impact on cognitive ability: a twin study

BACKGROUND

Though cognitive abilities in adulthood are largely influenced by individual genetic background, they have also been shown to be importantly influenced by environmental factors. Some of these influences are mediated by epigenetic mechanisms. Accordingly, polymorphic variants in the epigenetic gene DNMT3B have been linked to neurocognitive performance. Since monozygotic (MZ) twins may show larger or smaller intrapair phenotypic differences depending on whether their genetic background is more or less sensitive to environmental factors, a twin design was implemented to determine if particular polymorphisms in the DNMT3B gene may be linked to a better (worse) response to enriched (deprived) environmental factors.

METHODS

Applying the variability gene methodology in a sample of 54 healthy MZ twin pairs (108 individuals) with no lifetime history of psychopathology, two DNMT3B polymorphisms were analyzed in relation to their intrapair differences for either intellectual quotient (IQ) or working memory performance.

RESULTS

MZ twin pairs with the CC genotype for rs406193 SNP showed statistically significant larger intrapair differences in IQ than CT pairs.

CONCLUSIONS

Results suggest that DNMT3B polymorphisms may explain variability in the IQ response to either enriched or impoverished environmental conditions. Accordingly, the applied methodology is shown as a potentially valuable tool for determining genetic markers of cognitive plasticity. Further research is needed to confirm this specific result and to expand on other putative genetic markers of environmental sensitivity.

The effects of smoking on steroid metabolism and fetal programming

Tobacco addiction is a serious psychosocial and health problem. A pregnant woman who smokes not only influences the maternal organism, but also passes health risks on to the unborn child. A fetus exposed to maternal smoking is not only directly influenced, but is also endangered by a wide range of diseases up to his or her adult years. The components of tobacco smoke play a significant role in the development of a number of diseases for a large proportion of the smoking population, as well as among those pregnant. This article summarizes findings regarding the impacts on the production of steroid hormones - first describing the smoking-related changes in steroidogenesis in women, and then focusing on the influence of maternal smoking on the fetus's developing steroidogenesis. We assume that if during prenatal development the fetus has already been exposed to the effect of endocrine disruptors at the time fetal steroidogenesis begins fetal programming, this exposure can have serious pathophysiological effects both in the pregnancy as well as later in life. An example of such effects might be a delay in the creation of kidney adrenal androgens, which could also be evident on the level of steroid neuroactive metabolites that may influence the individual's psychological state and lead to later addictions.

Prenatal exposure to air pollution, maternal psychological distress, and child behavior

BACKGROUND

Airborne polycyclic aromatic hydrocarbons (PAHs) are pollutants generated by combustion of fossil fuel and other organic material. Both prenatal PAH exposure and maternal psychological distress during pregnancy have each been associated with neurodevelopmental problems in children. The goal was to evaluate potential interactions between prenatal exposure to airborne PAHs and maternal psychological distress during pregnancy on subsequent behavioral problems in children.

METHODS

In a longitudinal birth cohort study, 248 children of nonsmoking white women in the coal-burning region of Krakow, Poland, were followed from in utero until age 9. Prenatal PAH exposure was measured by personal air monitoring during pregnancy, maternal demoralization during pregnancy by the Psychiatric Epidemiology Research Instrument-Demoralization, and child behavior by the Child Behavior Checklist.

RESULTS

Significant interactions between maternal demoralization and PAH exposure (high versus low) were identified for symptoms of anxious/depressed, withdrawn/depressed, social problems, aggressive behavior, internalizing problems, and externalizing problems. The effects of demoralization on syndromes of anxious/depressed, withdrawn/depressed, rule-breaking, aggressive behavior, and the composite internalizing and externalizing scores were seen only in conjunction with high PAH exposure. Fewer significant effects with weaker effect sizes were observed in the low-PAH-exposure group.

CONCLUSIONS

Maternal demoralization during pregnancy appears to have a greater effect on child neurobehavioral development among children who experienced high prenatal PAH exposure. The results provide the first evidence of an interaction between prenatal exposure to maternal demoralization and air pollution on child neurobehavioral development, indicating the need for a multifaceted approach to the prevention of developmental problems in children.

Effects of maternal prenatal smoking and birth outcomes extending into the normal range on academic performance in fourth grade in North Carolina, USA

BACKGROUND

Research has documented the adverse relationship of child cognitive development with maternal prenatal smoking and poor birth outcomes. The potential, however, for maternal prenatal smoking to modify the association between birth outcomes and cognitive development is unclear.

METHODS

We linked statewide North Carolina birth data for non-Hispanic white and non-Hispanic black children to end-of-grade test scores in reading and mathematics at fourth grade (n = 65 677). We fit race-stratified multilevel models of test scores regressed on maternal smoking, birth outcomes (as measured by continuous and categorical gestational age and birthweight percentile for gestational age), and their interaction, controlling for maternal- and child-level socio-economic factors.

RESULTS

Smoking was consistently associated with decrements in test scores, and better birth outcomes were associated with improvements in test scores, even in clinically normal ranges. Test scores increased quadratically with improving birth outcomes among smoking and non-smoking mothers. Among non-Hispanic white children, the magnitude of the association between gestational age and test scores was larger for children whose mothers smoked during pregnancy compared with the non-smoking group. However, among non-Hispanic black children, birth outcomes did not appear to interact with maternal smoking on test scores.

CONCLUSIONS

Maternal prenatal smoking may interact with birth outcomes on reading and mathematics test scores, particularly among non-Hispanic white children. Improvements in birth outcomes, even within the clinically normal range, may be associated with improved academic performance. Pregnancy-related exposures and events exert a significant and long-term impact on cognitive development.

Tobacco smoke exposure during childhood: effect on cochlear physiology

The rate of smoking in Brazil is about 18.8%. Exposure to environmental tobacco smoke is one of the major factors predisposing children to several hazardous health problems. The objective of the present research was to analyze the effect of tobacco smoke exposure during childhood on cochlear physiology by measuring the transient evoked otoacoustic emissions (TEOAE) response levels. Cotinine, the main metabolite of nicotine, was measured in 145 students’ (8–10 years old) urine. Sixty students indicated tobacco smoke exposure (TSE) (cotinine urine levels ≥ 5.0 ng/mL) and 85 did not. The evaluation of TEOAE of TSE students showed lower response levels, mainly on frequencies of 2.8 kHz on the right and left ears and 2.0 kHz on left ear and lower signal noise response levels, mainly on the 1.0 kHz and 1.4 kHz frequencies, when compared to controls that were not exposed to tobacco. The mean hearing loss in tobacco smoke exposure children was 2.1 dB SPL. These results have important implications on the damage to the cochlear structures and indicate a possible loss in hearing and hearing ability development.

Factores asociados con el índice de masa corporal materno en un grupo de gestantes adolescentes, Medellín, Colombia

El estudio tuvo como objetivo evaluar la influencia de factores socioeconómicos, de seguridad alimentaria, de salud, y algunas medidas antropométricas, en la clasificación del índice de masa corporal (IMC) en un grupo de gestantes adolescentes de la ciudad de Medellín, Colombia, durante el tercer trimestre de gestación. Se realizó un estudio analítico observacional transversal con 294 gestantes. Para el análisis se utilizó un análisis bivariado y un modelo de regresión logística. La mayor probabilidad de presentar bajo peso gestacional la tuvieron aquellas gestantes cuyas familias devengaban menos de un salario mínimo (OR = 5,8; IC95%: 1,97-16,8). Ser menor de 15 años aumentó cuatro veces la probabilidad bajo peso gestacional y tener un perímetro del brazo y de pantorrilla por encima de 24cm y 32cm, respectivamente, reduce la probabilidad de presentar bajo peso gestacional en un 94% (perímetro de brazo: OR = 0,1; IC95%: 0,0-0,2); (perímetro de pantorrilla: OR = 0,1; IC95%: 0,0-0,2). Se concluye que los ingresos y la edad cronológica se asociaron con el bajo peso gestacional. Los perímetros de brazo y pantorrilla se correlacionaron de forma positiva con el peso materno.

Neurobehavioral phenotype of C57BL/6J mice prenatally and neonatally exposed to cigarette smoke

Although maternal cigarette smoking during pregnancy is a well-documented risk factor for a variety of adverse pregnancy outcomes, how prenatal cigarette smoke exposure affects postnatal neurobehavioral/cognitive development remains poorly defined. In order to investigate the cause of an altered behavioral phenotype, mice developmentally exposed to a paradigm of 'active' maternal cigarette smoke is needed. Accordingly, cigarette smoke exposed (CSE) and air-exposed C57BL/6J mice were treated for 6h per day in paired inhalation chambers throughout gestation and lactation and were tested for neurobehavioral effects while controlling for litter effects. CSE mice exhibited less than normal anxiety in the elevated zero maze, transient hypoactivity during a 1h locomotor activity test, had longer latencies on the last day of cued Morris water maze testing, impaired hidden platform learning in the Morris water maze during acquisition, reversal, and shift trials, and impaired retention for platform location on probe trials after reversal but not after acquisition or shift. CSE mice also showed a sexually dimorphic response in central zone locomotion to a methamphetamine challenge (males under-responded and females over-responded), and showed reduced anxiety in the light-dark test by spending more time on the light side. No differences on tests of marble burying, acoustic startle response with prepulse inhibition, Cincinnati water maze, matching-to-sample Morris water maze, conditioned fear, forced swim, or MK-801-induced locomotor activation were found. Collectively, the data indicate that developmental cigarette smoke exposure induces subnormal anxiety in a novel environment, impairs spatial learning and reference memory while sparing other behaviors (route-based learning, fear conditioning, and forced swim immobility). The findings add support to mounting evidence that developmental cigarette smoke exposure has long-term adverse effects on brain function.

Clinical and biochemical effects of environmental tobacco smoking on pregnancy outcome

The effects of environmental tobacco smoke (ETS) are less studied especially on neonates. This study evaluates the clinical and biochemical effects in neonates exposed to ETS during pregnancy. Two hundred pregnant women asked to complete the questioners about their ETS. Ninety from them were enrolled in biochemical assays as two groups according to ETS. The cotinine level determined in saliva and serum of mothers to confirm their tobacco exposure. The routine tracheal suction from the fetus was used to determine the level of neuron specific enolase (NSE), soluble E-cadherin, sApo-1/Fas, nitric oxide (NO) and cotinine. In clinical assessment, the percent of full term babies in non-exposed group (72 %) are higher compared to exposed group (67 %). Apgar score at the first min, admission to intensive care unit (ICU) and morbidity during the first month shows statistical significance increase in exposed compared to non-exposed group (p = 0.03, 0.05, 0.01, respectively). The new born weight in exposed group significantly decreased compared to non-exposed group (2,850 g ± 3.74 vs 2,967.67 g ± 3.34; p = 0.02). In biochemical assessment, NSE and sE-cadherin significantly increased, while NO significantly decreased (p = 0.000) in exposed compared to non-exposed group. There is a positive correlation between level of cotinine and both NSE, sE-cadherin (r = 0.7, 0.9; p = 0.000, 0.006, respectively). To our knowledge, this is the first study link between prenatal tobacco exposure (PTE) and biochemical parameters measured in tracheal suction. PTE will lead to decrease in birth weight most probably by decreasing NO, sFas, and increasing sE-cadherin. While, increased morbidity of neonates in the exposed group could be attributed to cessation of breast feeding and its complication and increased NSE in the studied markers.

The role of maternal smoking in effect of fetal growth restriction on poor scholastic achievement in elementary school

Fetal growth restriction and maternal smoking during pregnancy are independently implicated in lowering intellectual attainment in children. We hypothesized that only reduction of fetal growth that is attributable to extrinsic causes (e.g., maternal smoking) affects intellectual development of a child. Cross-sectional survey of 3,739 students in Nova Scotia (Canada) in 2003 was linked with the perinatal database, parental interviews on socio-demographic factors and the performance on standardized tests when primarily 11–12 years of age, thereby forming a retrospective cohort. Data was analyzed using hierarchical logistic regression with correction for clustering of children within schools. The risk of poor test result among children born small-for-gestational-age (SGA) to mothers who smoked was 29.4%, higher than in any other strata of maternal smoking and fetal growth. The adjusted odds ratio among SGA children born to mothers who smoked was the only one elevated compared to children who were not growth restricted and born to mothers who did not smoke (17.0%, OR = 1.46, 95% CI 1.02, 2.09). Other perinatal, maternal and socio-demographic factors did not alter this pattern of effect modification. Heterogeneity of etiology of fetal growth restriction should be consider in studies that address examine its impact on health over life course.

Variation in cognitive functioning as a refined approach to comparing aging across countries

Comparing the burden of aging across countries hinges on the availability of valid and comparable indicators. The Old Age Dependency Ratio allows only a limited assessment of the challenges of aging, because it does not include information on any individual characteristics except age itself. Existing alternative indicators based on health or economic activity suffer from measurement and comparability problems. We propose an indicator based on age variation in cognitive functioning. We use newly released data from standardized tests of seniors' cognitive abilities for countries from different world regions. In the wake of long-term advances in countries' industrial composition, and technological advances, the ability to handle new job procedures is now of high and growing importance, which increases the importance of cognition for work performance over time. In several countries with older populations, we find better cognitive performance on the part of populations aged 50+ than in countries with chronologically younger populations. This variation in cognitive functioning levels may be explained by the fact that seniors in some regions of the world experienced better conditions during childhood and adult life, including nutrition, duration and quality of schooling, lower exposure to disease, and physical and social activity patterns. Because of the slow process of cohort replacement, those countries whose seniors already have higher cognitive levels today are likely to continue to be at an advantage for several decades to come.

Maternal smoking during pregnancy: impact on otoacoustic emissions in neonates

OBJECTIVES

To determine the effect of maternal smoking during pregnancy on transient evoked otoacoustic emissions levels in neonates.

METHODS

This was a cross-sectional study investigating neonates in the maternity ward of a university hospital in the city of São Paulo, Brazil. A total of 418 term neonates without prenatal or perinatal complications were evaluated. The neonates were divided into two groups: a study group, which comprised 98 neonates born to mothers who had smoked during pregnancy; and a control group, which comprised 320 neonates born to mothers who had not. In order to compare the two ears and the two groups in terms of the mean overall response and the mean transient evoked otoacoustic emissions in response to acoustic stimuli delivered at different frequencies, we used analysis of variance with repeated measures.

RESULTS

The mean overall response and the mean frequency-specific response levels were lower in the neonates in the study group (p<0.001). The mean difference between the groups was 2.47 dB sound pressure level (95% confidence interval: 1.47-3.48).

CONCLUSIONS

Maternal smoking during pregnancy had a negative effect on cochlear function, as determined by otoacoustic emissions testing. Therefore, pregnant women should be warned of this additional hazard of smoking. It is important that smoking control be viewed as a public health priority and that strategies for treating tobacco dependence be devised.

Longitudinal study of smoking cessation before pregnancy and children's cognitive abilities at 56 months of age

BACKGROUND

An inverse relationship exists between the rates of maternal smoking during pregnancy and children's cognitive abilities. The effect of maternal cessation of smoking before pregnancy on child's cognitive development is less clear.

AIMS

To study whether maternal cessation of smoking before pregnancy is associated with children's cognitive abilities.

STUDY DESIGN AND SUBJECTS

The original cohort included all 1535 live-born infants admitted to the neonatal wards during 1 year and 658 randomly recruited non-admitted infants. The present study sample comprised 1019 (68.2%) children of the original sample born at term and free of any major impairment followed up to 56 months.

OUTCOME MEASURES

Child's general reasoning, visual-motor integration, verbal competence, and language comprehension at 56 months of age.

RESULTS

The results showed that children whose mothers smoked >10 cigarettes per day before pregnancy but none during pregnancy, fared 12.07 (95% confidence interval [CI]: 4.07 to 20.08) and 11.23 (95% CI: 2.81 to 19.66) age-standardized points poorer in general reasoning and in language comprehension tests, respectively, than children of never-smokers. All results were adjusted for the sex, gestational age-adjusted birth weight, multiple/singleton pregnancy, birth order, preeclampsia, maternal diabetes, admission to neonatal ward, 5-minute Apgar score (<7), breastfeeding, parental level of education, maternal age, BMI at the end of pregnancy and single parenting.

CONCLUSIONS

Heavy smoking before pregnancy is associated with children's lower cognitive abilities even if the mother has quit smoking before pregnancy. Identification and intervention of heavy smoking women of fertile age would potentially improve not only their odds to become pregnant but also benefit the offspring's cognitive functioning.