Socioeconomic differences and the impact of being small for gestational age on neurodevelopment among preschool-aged children

Perinatal Factors Associated with Autism Spectrum Disorder in Jamaican Children

Mode of delivery, preterm birth, and low birth weight (LBW) are hypothesized to be associated with autism spectrum disorder (ASD) in the offspring. Using data from 343 ASD cases (2-8 years) and their age- and sex-matched typically developing controls in Jamaica we investigated these hypotheses. Our statistical analyses revealed that the parish of residence could modify the association between cesarean delivery and ASD, with a difference found in this relationship in Kingston parish [matched odds ratio (MOR) (95% confidence interval (CI)) 2.30 (1.17-4.53)] and other parishes [MOR (95% CI) 0.87 (0.48-1.59)]. Although the associations of LBW and preterm birth with ASD were not significant, we observed a significant interaction between LBW and the household socioeconomic status. These findings require replication.

Association of Intrauterine Growth Restriction and Small for Gestational Age Status With Childhood Cognitive Outcomes: A Systematic Review and Meta-analysis

IMPORTANCE

The magnitude of the association of intrauterine growth restriction (IUGR) and small for gestational age (SGA) status with cognitive outcomes in preterm and term-born children has not been established.

OBJECTIVE

To examine cognitive outcomes of preterm and term-born children who had IUGR and were SGA compared with children who were appropriate for gestational age (AGA) during the first 12 years of life.

DATA SOURCES

For this systematic review and meta-analysis, the Scopus, PubMed, Web of Science, Science Direct, PsycInfo, and ERIC databases were searched for English-language, peer-reviewed literature published between January 1, 2000, and February 20, 2020. The following Medical Subject Heading terms for IUGR and SGA and cognitive outcomes were used: intrauterine growth restriction, intrauterine growth retardation, small for gestational age AND neurodevelopment, neurodevelopmental outcome, developmental outcomes, and cognitive development.

STUDY SELECTION

Inclusion criteria were assessment of cognitive outcomes (full-scale IQ or a cognitive subscale), inclusion of an AGA group as comparison group, and inclusion of gestational age at birth and completion of cognitive assessment up to 12 years of age.

DATA EXTRACTION AND SYNTHESIS

The Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines were followed. Data were double screened for full-text articles, and a subset were independently coded by 2 authors. Standardized mean differences (SMDs) and odd ratios from individual studies were pooled by applying random-effects models.

MAIN OUTCOMES AND MEASURES

Cognitive outcomes, defined as mental, cognitive, or IQ scores, estimated with standardized practitioner-based cognitive tests or as borderline intellectual impairment (BII), defined as mental, cognitive, or IQ scores at least 1 SD below the mean cognitive score.

RESULTS

In this study of 89 samples from 60 studies including 52 822 children, children who had IUGR and were SGA had significantly poorer cognitive outcomes (eg, cognitive scores and BII) than children with AGA in childhood. For cognitive scores, associations are consistent for preterm (SMD, -0.27; 95% CI, -0.38 to -0.17) and term-born children (SMD, -0.39; 95% CI, -0.50 to -0.28), with higher effect sizes reported for term-born IUGR and AGA group comparisons (SMD, -0.58; 95% CI, -0.82 to -0.35). Analyses on BII revealed a significantly increased risk in the preterm children who had IUGR and were SGA (odds ratio, 1.57; 95% CI, 1.40-1.77) compared with the children with AGA.

CONCLUSIONS AND RELEVANCE

Growth vulnerabilities assessed antenatally (IUGR) and at the time of birth (SGA) are significantly associated with lower childhood cognitive outcomes in preterm and term-born children compared with children with AGA. These findings highlight the need to develop interventions that boost cognitive functions in these high-risk groups.

Can increased resistance to uterine artery flow be a risk factor for adverse neurodevelopmental outcomes in childhood? A prospective cohort study

A prospective cohort study was conducted to determine whether an increased uterine artery pulsatility index (UtA-PI) in the second trimester of pregnancy is a risk factor for neurodevelopmental outcomes in children 2-3 years of age. A group of pregnant women with a UtA-PI below the 90th percentile (P90) and a second group with a UtA-PI ≥ P90 in the second trimester were included in this study. The children of these women were evaluated during their second or third year of life using the Bayley III Screening Test. A total of 858 pregnancies with UtA-PI < P90 and 96 pregnancies with UtA-PI ≥ 90 were studied. The differences between the groups related to UtA-PI ≥ 90 were detected in relation to the variables of the Caucasian ethnicity, hypertension, newborn weight and stay in the intensive care unit after birth. However, adjusted neurodevelopmental outcomes did not differ between the groups: OR 0.53 (95% CI 0.27-1.04%). This study failed to demonstrate that the UtA-PI is a risk factor for adverse neurodevelopment in children.Impact statementWhat is already known on this subject? Early interventions in children at high risk for neurodevelopmental deficiency have proved to be beneficial. The complications associated with gestation and delivery negatively influence neurodevelopment. Several studies have shown that some adverse pregnancy outcomes such as preeclampsia, foetal growth restriction and foetal death can be predicted by increased resistance to flow in the uterine artery in the second trimester. However, there are no studies evaluating the association of the uterine artery with neurodevelopmental results.What do the results of this study add? This study concludes that neurodevelopment is influenced by multiple environmental and intrinsic factors and cannot be predicted by only one variable, such as the uterine artery blood flow. The brain has repair mechanisms to attenuate insults that occur during gestation and delivery.What are the implications of these findings for clinical practice and/or further research? This study was unable to demonstrate that blood flow in the uterine artery is a risk factor for neurodevelopment. Different, larger studies should be conducted by combining other factors with the uterine artery in an algorithm to allow the early identification of children at risk for neurodevelopmental impairment.

Preterm Birth, Poverty, and Cognitive Development

BACKGROUND

Preterm birth and childhood poverty each adversely impact children's cognitive development and academic outcomes. In this study, we investigated whether the relationships between preterm and early term birth and children's cognitive scores at 3, 5, and 7 years old were modified by childhood poverty.

METHODS

This study was conducted by using data on singletons born at 24 to 40 weeks' gestation enrolled in the Millennium Cohort Study in the United Kingdom. Linear regression models were used to test independent and joint associations of gestational age (early or moderate preterm, late preterm, or early term compared with term) and childhood poverty (<60% of median UK income) with children's cognitive scores. Presence of additive interaction between gestational age and poverty was tested by using interaction terms.

RESULTS

Children born preterm (<37 weeks) or early term (37-38 weeks) tended to score more poorly on cognitive assessments than children born at term (39-40 weeks). The estimated deficits were ∼0.2 to 0.3 SD for early or moderate preterm, 0.1 SD for late preterm, and 0.05 SD for early term compared with term. Children living in poverty scored 0.3 to 0.4 SD worse than children not living in poverty on all assessments. For most assessments, the estimated effects of the 2 factors were approximately additive, with little or no evidence of interaction between gestational age and poverty.

CONCLUSIONS

Although children born preterm who lived in poverty had the poorest cognitive outcomes, living in poverty did not magnify the adverse effect of being preterm on cognitive development.

Comparison of Perinatal Risk Factors Associated with Autism Spectrum Disorder (ASD), Intellectual Disability (ID), and Co-occurring ASD and ID

While studies report associations between perinatal outcomes and both autism spectrum disorder (ASD) and intellectual disability (ID), there has been little study of ASD with versus without co-occurring ID. We compared perinatal risk factors among 7547 children in the 2006-2010 Autism and Developmental Disability Monitoring Network classified as having ASD + ID, ASD only, and ID only. Children in all three groups had higher rates of preterm birth (PTB), low birth weight, small-for-gestational-age, and low Apgar score than expected based on the US birth cohort adjusted for key socio-demographic factors. Associations with most factors, especially PTB, were stronger for children with ID only than children with ASD + ID or ASD only. Associations were similar for children with ASD + ID and ASD only.

Maternal fat mass at mid-pregnancy and birth weight in Brazilian women

BACKGROUND

The relationship between maternal body composition and foetal development is unclear.

AIM

To determine the relationship between maternal body composition [fat mass (FM) and fat-free mass (FFM)] and foetal growth and birth weight, independent of potential confounding factors.

SUBJECTS AND METHODS

This study consisted of 92 women, normal and overweight/obese, recruited from the Instituto Fernandes Figueira in Rio de Janeiro, Brazil. Body composition (FM and FFM) was estimated using bioelectrical impedance. Foetal growth was assessed using serial ultrasound measurements at the second and third trimester and infant's weight and length were measured at birth. Multiple linear regression analyses were used to determine the association between maternal FM and FFM and birth weight adjusted for gestational age (BWt) and change in estimated foetal weight (ΔEFW), controlling for infant gender, maternal serum glucose, energy intake, parity, height and income.

RESULTS

Maternal FM, but not FFM, was positively associated with BWt (p = 0.02) and borderline with ΔEFW (p = 0.05). FM expressed as a percentage of body weight (%FM) showed a significant positive association with BWt (p < 0.001) and ΔEFW (p < 0.01). Using backward linear regression analysis, FM was a significant predictor of BWt (p < 0.001) and ΔEFW (p = 0.03), but not change in femur length.

CONCLUSION

In this small sample of normal and overweight/obese women, maternal FM at mid-pregnancy is associated with neonatal BW and foetal growth.

Maternal prepregnancy body mass index and child psychosocial development at 6 years of age

BACKGROUND

Both obesity and developmental disabilities have increased in recent decades. Limited studies suggest associations between maternal prepregnancy obesity and child neurodevelopment.

METHODS

The Infant Feeding Practices Study II, a US nationally distributed longitudinal study of maternal health and infant health and feeding practices, was conducted from 2005 to 2007. In 2012, mothers were recontacted for information on their children's health and development. We examined associations between maternal prepregnancy BMI and child psychosocial development in 1311 mother-child pairs included in this follow-up study. Children's development was assessed by maternal report of child psychosocial difficulties from the Strengths and Difficulties Questionnaire, past developmental diagnoses, and receipt of special needs services.

RESULTS

Adjusting for sociodemographic factors, children of obese class II/III mothers (BMI >35.0) had increased odds of emotional symptoms (adjusted odds ratio [aOR] 2.24; 95% confidence interval [CI], 1.27-3.98), peer problems (aOR 2.07; 95% CI, 1.26-3.40), total psychosocial difficulties (aOR 2.17; 95% CI, 1.24-3.77), attention-deficit/hyperactivity disorder diagnosis (aOR 4.55; 95% CI, 1.80-11.46), autism or developmental delay diagnosis (aOR 3.13; 95% CI, 1.10-8.94), receipt of speech language therapy (aOR 1.93; 95% CI, 1.18-3.15), receipt of psychological services (aOR 2.27; 95% CI, 1.09-4.73), and receipt of any special needs service (aOR 1.99; 95% CI, 1.33-2.97) compared with children of normal weight mothers (BMI 18.5-24.9). Adjustment for potential causal pathway factors including pregnancy weight gain, gestational diabetes, breastfeeding duration, postpartum depression, and child's birth weight did not substantially affect most estimates.

CONCLUSIONS

Children whose mothers were severely obese before pregnancy had increased risk for adverse developmental outcomes.

SGA children: auxological and metabolic outcomes - the role of GH treatment

The definition Small for Gestational Age (SGA) describes those newborns weighing and/or measuring in length <-2 SD than expected for their gestational age. These subjects are at higher risk of short stature, neonatal complications, alterations of glucose, lipid metabolism, body composition, bone metabolism and puberty, neurocognitive vulnerabilities and alterations of the GH-IGF-I axis. With regards to growth, in 85-90% of the cases children born SGA experience a period of catch up growth that allows them to achieve an adult stature within normal range. In a 10-15% of the cases, the catch up growth period does not take place and this entails short stature in adulthood. In the latter group, GH treatment may be considered to achieve adult height in the range of genetical target stature. With reference to glucose and lipid metabolism, young adults born SGA and particularly those with early catch up growth are at higher risk of developing insulin resistance, type 2 diabetes mellitus, arterial hypertension, dyslipidemia, overweight, obesity and metabolic syndrome. Subjects born SGA are in need of a correct diagnostic and eventually therapeutic approach.

Socioeconomic status, child enrichment factors, and cognitive performance among preschool-age children: results from the Follow-Up of Growth and Development Experiences study

Lower cognitive performance is associated with poorer health and functioning throughout the lifespan and disproportionately affects children from lower socioeconomic status (SES) populations. Previous studies reporting positive associations between child home enrichment and cognitive performance generally had a limited distribution of SES. We evaluated the associations of SES and child enrichment with cognitive performance in a population with a wide range of SES, particularly whether enrichment attenuates associations with SES. Children were sampled from a case-control study of small-for-gestational-age (SGA) conducted in a public hospital serving a low SES population (final n=198) and a private hospital serving a middle-to-high SES population (final n=253). SES (maternal education and income) and perinatal factors (SGA, maternal smoking and drinking) were obtained from maternal birth interview. Five child home enrichment factors (e.g. books in home) and preschool attendance were obtained from follow-up interview at age 4.5 years. Cognitive performance was assessed with the Differential Ability Scales (DAS), a standardized psychometric test administered at follow-up. SES and enrichment scores were created by combining individual factors. Analyses were adjusted for perinatal factors. Children from the public birth hospital had a significantly lower mean DAS general cognitive ability (GCA) score than children born at the private birth hospital (adjusted mean difference -21.4, 95% CI: -24.0, -18.7); this was substantially attenuated by adjustment for individual SES, child enrichment factors, and preschool attendance (adjusted mean difference -5.1, 95% CI: -9.5, -0.7). Individual-level SES score was associated with DAS score, beyond the general SES effect associated with hospital of birth. Adjustment for preschool attendance and home enrichment score attenuated the association between individual SES score and adjusted mean DAS-GCA among children born at both of the hospitals. The effect of being in the lower compared to the middle tertile of SES score was reduced by approximately a quarter; the effect of being in the upper compared to the middle tertile of SES score was reduced by nearly half, but this comparison was possible only for children born at the private hospital. A child's individual SES was associated with cognitive performance within advantaged and disadvantaged populations. Child enrichment was associated with better cognitive performance and attenuated the SES influence. Health care providers should reinforce guidelines for home enrichment and refer children with delays to early intervention and education, particularly children from disadvantaged populations.

The Effects of Arsenic Exposure on Neurological and Cognitive Dysfunction in Human and Rodent Studies: A Review

Arsenic toxicity is a worldwide health concern as several millions of people are exposed to this toxicant via drinking water, and exposure affects almost every organ system in the body including the brain. Recent studies have shown that even low concentrations of arsenic impair neurological function, particularly in children. This review will focus on the current epidemiological evidence of arsenic neurotoxicity in children and adults, with emphasis on cognitive dysfunction, including learning and memory deficits and mood disorders. We provide a cohesive synthesis of the animal studies that have focused on neural mechanisms of dysfunction after arsenic exposure including altered epigenetics; hippocampal function; glucocorticoid and hypothalamus-pituitary-adrenal axis (HPA) pathway signaling; glutamatergic, cholinergic and monoaminergic signaling; adult neurogenesis; and increased Alzheimer’s-associated pathologies. Finally, we briefly discuss new studies focusing on therapeutic strategies to combat arsenic toxicity including the use of selenium and zinc.

Impact of caste on the neurodevelopment of young children from birth to 36 months of age: a birth cohort study in Chitwan Valley, Nepal

Background

Caste, a proxy of socioeconomic position, can influence the neurodevelopment of children through several pathways, including exposure to toxic elements. Studies from developing countries where caste is represented by prevailing caste groups and people are highly exposed to toxic elements can provide useful insights into the mechanisms of neurodevelopmental inequities among children. This study aims to investigate the impact of caste on the neurodevelopment of children from birth to 36 months of age in Chitwan Valley, Nepal, where people are exposed to high levels of arsenic (As) and lead (Pb).

Methods

Participants (N = 94) were mother-infant pairs from the Chitwan district in Nepal. The neurodevelopment of the infants was assessed using the Brazelton Neonatal Behavioral Assessment Scale, Third Edition, (NBAS III) at birth and the Bayley Scales of Infant Development, Second Edition, (BSID II) at ages 6, 24, and 36 months. Caste was categorized based on surname, which, in Nepal generally refers to one of four caste groups. We also measured the concentrations of As and Pb in cord blood.

Results

Caste was positively associated with the state regulation cluster score of the NBAS III at birth after adjustment for covariates (p for trend < 0.01). Adding cord blood As levels attenuated the association (p for trend = 0.12). With regard to neurodevelopment at six months of age, the third-ranked caste group scored higher than the first-ranked caste group on the Mental Development Index (MDI) of the BSID II (coefficient = 3.7; 95% confidence interval (CI) = 1.3 to 6.0). This difference remained significant after adjustment for cord blood As levels and other covariates was made (coefficient = 3.9; 95% CI = 1.2 to 6.7). The remaining clusters of the NBAS III and BSID II at 6, 24, and 36 months were not significantly associated with caste group.

Conclusions

Caste was positively associated with the state regulation cluster score of NBAS III at birth. This association was partially mediated by cord blood As levels. However, the negative impact of caste on neurodevelopment disappeared as the children grew. Furthermore, an inverse association between caste and MDI at six months of age was observed. Additional studies are needed to elucidate the mechanism of how caste affects neurodevelopment.