Prenatal and perinatal factors associated with intellectual disability

Regional differences in autism and intellectual disability risk associated with cesarean section delivery

Prior epidemiological studies investigating the association between delivery mode (i.e., vaginal birth and cesarean section [C-section]) and autism spectrum disorder (ASD) and intellectual disability (ID) risk have reported mixed findings. This study examined ASD and ID risks associated with primary and repeat C-section within diverse US regions. During even years 2000-2016, 8-years-olds were identified with ASD and/or ID and matched to birth records [ASD only (N = 8566, 83.6% male), ASD + ID (N = 3445, 79.5% male), ID only (N = 6158, 60.8% male)] using the Centers for Disease Control and Prevention's Autism and Developmental Disabilities Monitoring Network methodology. The comparison birth cohort (N = 1,456,914, 51.1% male) comprised all births recorded in the National Center for Health Statistics corresponding to birth years and counties in which surveillance occurred. C-section rates in the birth cohort demonstrated significant regional variation with lowest rates in the West. Overall models demonstrate increased odds of disability associated with primary and repeat C-section. Adjusted models, stratified by region, identified significant variability in disability likelihood associated with repeat C-section: increased odds occurred for all case groups in the Southeast, for ASD only and ID only in the Mid-Atlantic, and no case groups in the West. Regional variability in disability risk associated with repeat C-section coincides with differences in birth cohorts' C-section rates. This suggests increased likelihood of disability is not incurred by the procedure itself, but rather C-section serves as a proxy for exposures with regional variability that influence fetal development and C-section rates.

Machine learning analysis with population data for prepregnancy and perinatal risk factors for the neurodevelopmental delay of offspring

Neurodevelopmental disorders (NDD) in offspring are associated with a complex combination of pre-and postnatal factors. This study uses machine learning and population data to evaluate the association between prepregnancy or perinatal risk factors and the NDD of offspring. Population-based retrospective cohort data were obtained from Korea National Health Insurance Service claims data for 209,424 singleton offspring and their mothers who gave birth for the first time in 2007. The dependent variables were motor development disorder (MDD), cognitive development disorder (CDD) and combined overall neurodevelopmental disorder (NDD) from offspring. Seventeen independent variables from 2002 to 2007 were included. Random forest variable importance and Shapley Additive Explanation (SHAP) values were calculated to analyze the directions of its associations with the predictors. The random forest with oversampling registered much higher areas under the receiver-operating-characteristic curves than the logistic regression of interaction and non-linearity terms, 79% versus 50% (MDD), 82% versus 52% (CDD) and 74% versus 50% (NDD). Based on random forest variable importance, low socioeconomic status and age at birth were highly ranked. In SHAP values, there was a positive association between NDD and pre- or perinatal outcomes, especially, fetal male sex with growth restriction associated the development of NDD in offspring.

The association between maternal infection and intellectual disability in children: A systematic review and meta-analysis

BACKGROUND

There is arguing evidence regarding the association between maternal infections during pregnancy and the risk of intellectual disability (ID) in children. This systematic review and meta-analysis are essential to determine and address inconsistent findings between maternal infections during pregnancy and the risk of ID in children.

METHODS

The MOOSE and PRISMA guidelines were followed to perform and report on this study. The Medline/PubMed, Web of Science, Embase, and Scopus databases were searched from inception up to March 15, 2023, to identify potentially eligible studies. Inclusion and exclusion criteria were applied, as well as the Newcastle-Ottawa Scale was used to assess the methodological quality of studies included. The included studies were divided into two types based on the participants: (1) ID-based studies, which involved children with ID as cases and healthy children as controls and evaluated maternal infection in these participants; (2) infection-based studies, which assessed the prevalence or incidence of ID in the follow-up of children with or without exposure to maternal infection. We used Random-effects models (REM) to estimate the overall pooled odds ratio (OR) and 95% confidence intervals (CIs). The between-studies heterogeneity was assessed with the χ2-based Q-test and I2 statistic. Subgroup and sensitivity analyses were applied to explore the source of heterogeneity and results consistency.

RESULTS

A total of eight studies including 1,375,662 participants (60,479 cases and 1,315,183 controls) met the eligibility criteria. The REM found that maternal infection significantly increased the risk of ID in children (OR, 1.33; 95% CI, 1.21-1.46; I2 = 64.6). Subgroup analysis showed a significant association for both infection-based (OR, 1.27; 95%CI, 1.15-1.40; I2 = 51.2) and ID-based (OR, 1.44; 95%CI, 1.19-1.74; I2 = 77.1) studies. Furthermore, subgroup analysis based on diagnostic criteria revealed a significant association when maternal infection or ID were diagnosed using ICD codes (OR, 1.33; 95% CI, 1.20-1.48; I2 = 75.8).

CONCLUSION

Our study suggests that maternal infection during pregnancy could be associated with an increased risk of ID in children. This finding is consistent across different types of studies and diagnostic criteria. However, due to the heterogeneity and limitations of the included studies, we recommend further longitudinal studies to confirm the causal relationship and the underlying mechanisms.

Random capillary glucose levels throughout pregnancy, obstetric and neonatal outcomes, and long-term neurodevelopmental conditions in children: a group-based trajectory analysis

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with both short- and long-term risks, although it is unknown if risks vary by severity, timing, and duration of gestational hyperglycemia. We aimed to identify trajectories of random capillary glucose (RCG) levels throughout pregnancy and assess their associations with both obstetric/neonatal outcomes and children's risk of neurodevelopmental conditions (NDCs) (i.e., autism, intellectual disability, and attention-deficit/hyperactivity disorders [ADHD]).

METHODS

A population-based cohort study was conducted involving 76,228 children born to 68,768 mothers without pregestational diabetes. Group-based trajectory modeling was utilized to identify distinct glucose trajectories across RCG values throughout the course of pregnancy. The associations between these trajectory groups and obstetric/neonatal outcomes as well as children's NDCs were then assessed using generalized estimating equation models with a logit link. The Benjamini-Hochberg (BH) procedure was employed to adjust P-values for multiple comparisons, controlling the false discovery rate (FDR).

RESULTS

Five distinct glucose trajectory groups were identified, each with varying percentages diagnosed with GDM. Their associations with obstetric/neonatal outcomes as well as children's NDCs varied. For example, when compared to the "Persistently Low" group, other groups exhibited varying degrees of increased risk for large-for-gestational-age babies, with the exception of the "High in Early Pregnancy" group. Compared to the "Persistently Low" group, all other trajectory groups were associated with NDC outcomes, except the "High in Mid-Pregnancy" group. However, none of the associations with offspring NDCs remained significant after accounting for the FDR correction.

CONCLUSIONS

Persistent high glucose levels or moderately elevated glucose levels throughout pregnancy, as well as transient states of hyperglycemia in early or mid-pregnancy, were found to be associated with increased risks of specific obstetric and neonatal complications, and potentially offspring NDCs. These risks varied depending on the severity, timing, duration, and management of hyperglycemia. The findings underscore the need for continuous surveillance and individualized management strategies for women displaying different glucose trajectories during pregnancy. Limitations such as potential residual confounding, the role of mediators, and small sample size should be addressed in future studies.

Relationship of Nonsteroidal Anti-Inflammatory Drug Use During Pregnancy with Autism Spectrum Disorder and Intellectual Disability Among Offspring

Objective: This study aimed to examine the association of nonsteroidal anti-inflammatory drug (NSAID) use by pregnant women during pregnancy with autism spectrum disorder (ASD) and intellectual disability (ID) in their children among Medicaid-insured mother-child dyads. Materials and Methods: We conducted a retrospective cohort study linking multiple datasets of South Carolina for the years between 2010 and 2017, in which the main exposure variable was NSAID use during pregnancy and outcome variables were ASD only, ID only, and ASD with ID. We conducted a multinomial logistic regression analysis, controlling for identified risk factors for ASD (mother's age, race, body-mass index, preeclampsia, and gestational diabetes). Results: NSAID use during pregnancy was found to be associated with ID only in both unadjusted and adjusted analyses. Children with mothers who had NSAID prescriptions were 26% more likely to have ID in comparison with children whose mothers did not have NSAID prescriptions (odds ratio: 1.26 [1.10-1.46]). The other risk factors identified for ASD were maternal age, race, preeclampsia, smoking, low birth weight, and obesity. For ID, the risk factors were maternal age, race, smoking, birth weight, overweight, and obesity, all of which were also associated with ASD with ID, except for overweight. Conclusions: NSAID usage during pregnancy was found to be associated with ID only and not with ASD. However, more research is needed to validate the effect of NSAIDs during pregnancy on ASD and ID among children.

Intellectual functioning in survivors of extremely low birthweight: Cognitive outcomes in childhood and adolescence

BACKGROUND

Infants born at extremely low birthweight (ELBW: ≤1000 g) are vulnerable to intellectual disabilities, but the factors that may distinguish between ELBW survivors with and without these impairments are not well understood. In this study, prospective associations between neonatal factors and functional outcomes in childhood and adolescence were compared in ELBW survivors with and without borderline intellectual functioning (BIF).

METHODS

Borderline intellectual functioning was defined by IQ < 85, assessed at 8 years. Among 146 ELBW survivors, 48 (33%) had IQ scores under 85, and 98 (67%) had scores equal to or over 85. Group differences in demographic and risk factors were assessed via t-test, chi-squared analysis or non-parametric tests. Neonatal factors that differed between ELBW groups were tested for association with adaptive behaviour assessed at age 5 years, and reading and arithmetic skills assessed at ages 8 and 15 years, using hierarchical regression models.

RESULTS

Extremely low birthweight survivors with BIF had significantly lower birthweights than ELBW survivors without BIF (790 vs. 855 g, P < 0.01) and were more likely to be born to mothers with lower socioeconomic status (SES) (78% vs. 48%, P < 0.01). These ELBW survivors also were more likely to be diagnosed with significant neurosensory impairment (NSI; 35% vs. 19%, P < 0.04), experienced more bronchopulmonary dysplasia (56% vs. 38%, P < 0.04), received more days of respiratory support (median 33 vs. 14 days, P < 0.01) and remained in hospital for longer periods (median 81 vs. 63 days, P < 0.03). Birthweight, familial SES, NSI and duration of respiratory support were significant predictors for one or more outcomes. Across groups, lower familial SES was associated with lower academic scores (Ps < 0.05), and NSI predicted lower adaptive functioning (Ps < 0.001). Other associations were moderated by group: among ELBW survivors with BIF, heavier birthweights predicted better arithmetic skills, the presence of NSI was associated with poorer arithmetic skills and more ventilation days predicted poorer reading skills.

CONCLUSIONS

At birth, ELBW survivors with BIF faced more physiological and social disadvantages and required more medical intervention than their ELBW peers without BIF. Smaller birth size, NSI burden and prolonged neonatal ventilatory support displayed gradients of risk for childhood and adolescent academic outcomes across groups. Whereas academic performance in ELBW survivors with BIF was sensitive to variation in birth size, NSI or ventilation days, ELBW survivors without BIF attained thresholds of intellectual ability that were sufficient to support higher levels of academic performance at both ages, regardless of their status on these factors. The findings are discussed in relation to Zigler's developmental theory of intellectual disability.

Trimester-specific ambient PM2.5 exposures and risk of intellectual disability in Utah

Prenatal fine particulate matter (PM2.5) exposure is an understudied risk factor for neurodevelopmental outcomes, including intellectual disability (ID). Associations among prenatal exposures and neurodevelopmental outcomes may vary depending on the timing of exposure. Limited numbers of studies examining PM2.5 and neurodevelopmental outcomes have considered exposures occurring during the preconception period. To address these gaps, we conducted a case-control study of children born in Utah between 2002 and 2008 (n = 1032). Cases were identified using methods developed by the Centers for Disease Control and Prevention's Autism and Developmental Disabilities Monitoring Network and matched with controls on birth year, sex, and birth county. We estimated the daily average PM2.5 concentration during a period spanning 12 weeks before the estimated conception date, as well as during each of the three trimesters at the maternal residential address listed on the child's birth certificate. In a multivariable model, the third (OR: 2.119, CI: 1.123-3.998, p = .021) and fourth (OR: 2.631, CI: 1.750-3.956, p < .001) quartiles for preconception average PM2.5 demonstrated significantly increased risk of ID relative to the first quartile. Second quartile preconception exposure was also associated with increased risk, though it did not reach significance (OR: 1.385, CI: 0.979-1.959, p = .07). The fourth quartile of first trimester average PM2.5 was positive and significant (OR: 2.278, CI: 1.522-3.411, p < .001); the third quartile was positive, but not significant (OR: 1.159, CI: 0.870-1.544, p = .312). Quartiles of second and third trimester were not associated with higher risk of ID. These findings from Utah, which were robust to a variety of sensitivity analyses, provide initial evidence that preconception and prenatal PM2.5 exposure may be associated with ID. Future studies are needed across other geographic locations and populations.

Pre-/perinatal reduced optimality and neurodevelopment at 1 month and 3 years of age: Results from the Japan Environment and Children's Study (JECS)

Neurodevelopmental disorders (NDDs) in children are associated with a complex combination of genetic and/or environmental factors. Pre-/perinatal events are major known environmental suboptimal factors, and their individual and combined contributions vary. This study investigated the association between pre-/perinatal reduced optimality and child development observed by parents at 1 month, as well as NDDs at 3 years of age (i.e., motor delay, intellectual disability, developmental language disorder, and autism spectrum disorder), in the context of the Japan Environment and Children's Study. The study also assessed whether child development at 1 month predicted NDDs at 3 years of age. Associations between 25 pre-/perinatal factors and (a) developmental concerns at 1 month of age and (b) NDDs at 3 years were analyzed (n = 71,682). Binomial regression models were used to investigate risk ratios of the developmental outcome at each time point for total pre-/perinatal reduced optimality scale scores, as well as for individual pre-/perinatal factors of the reduced optimality scale. Finally, we assessed the ability of parental observations of offspring development at 1 month to predict NDDs at 3 years. Total reduced optimality scores were positively associated with 1-month developmental concerns and 3-year NDDs, with higher scores (i.e., a reduction in optimality) associated with an increased risk of both NDDs and earlier parental concerns. Neonatal transportation, epidural analgesia, advanced maternal age, cesarean section delivery, Apgar score ≤8, and hyperbilirubinemia were identified as individual risk factors for 3-year NDDs, overlapping with 14 risk factors for 1-month developmental concerns except Apgar score ≤8. Among six developmental items assessed at 1 month of age, concerns about gross motor function and difficulty holding/trouble calming down had the strongest associations with later-diagnosed motor delay and autism spectrum disorder, respectively. Five perinatal factors and advanced maternal age were associated with NDD at 3 years of age, as were early parental developmental concerns regarding their offspring's overall development, indicating the importance of careful follow-up of offspring born with pre-/perinatal reduced optimality. The results also implicated early parental concerns, as early as 1 month, may also be a useful indicator of later NDD status.

Associations between estimates of perinatal industrial pollution exposures and intellectual disability in Utah children

While heavy metals exposure is associated with intellectual disability (ID), little is known about associations between industrial pollution and ID. The objective of this analysis is to assess associations between estimated perinatal industrial pollution exposures from the US Environmental Protection Agency's Risk Screening Environmental Indicators Microdata and children's ID risk. We conducted a case-control study of children born in Utah from 2000 to 2008 (n = 1679). Cases were identified through the Center for Disease Control's Autism and Developmental Disabilities Monitoring Network's Utah site and matched with controls based on birth year, sex, and birth county. We used multivariable generalized estimating equations to examine associations between estimated perinatal industrial pollution exposures and ID risk. The fourth quartile of industrial pollution exposure was associated with increased odds of ID relative to the first (Odds Ratio [OR]: 1.73, 95% Confidence Interval [CI]: 1.23-2.44) and second (OR: 1.67, CI: 1.19-2.35) quartiles. Similarly, the third quartile was associated with increased odds of ID relative to the first (OR: 1.47, CI: 1.06-2.03) and second (OR: 1.41, CI: 1.02-1.96) quartiles. Findings were robust to varied model specifications. Maternal residential exposures to industrial pollution were associated with increased ID prevalence in Utah. Since environmental correlates of ID are understudied, additional research is needed.

SPTBN5, Encoding the βV-Spectrin Protein, Leads to a Syndrome of Intellectual Disability, Developmental Delay, and Seizures

Whole exome sequencing has provided significant opportunities to discover novel candidate genes for intellectual disability and autism spectrum disorders. Variants in the spectrin genes SPTAN1, SPTBN1, SPTBN2, and SPTBN4 have been associated with neurological disorders; however, SPTBN5 gene-variants have not been associated with any human disorder. This is the first report that associates SPTBN5 gene variants (ENSG00000137877: c.266A>C; p.His89Pro, c.9784G>A; p.Glu3262Lys, c.933C>G; p.Tyr311Ter, and c.8809A>T; p.Asn2937Tyr) causing neurodevelopmental phenotypes in four different families. The SPTBN5-associated clinical traits in our patients include intellectual disability (mild to severe), aggressive tendencies, accompanied by variable features such as craniofacial and physical dysmorphisms, autistic behavior, and gastroesophageal reflux. We also provide a review of the existing literature related to other spectrin genes, which highlights clinical features partially overlapping with SPTBN5.

Defective Placentation Syndromes and Intellectual Disability in the Offspring: Nationwide Cohort and Sibling-Controlled Studies

We investigated the relationships between syndromic manifestations of defective placentation and the incidence of intellectual disability (ID) in offspring by conducting a population-based cohort study of 1,581,200 nonmalformed, live singleton infants born in Sweden between 1998 and 2014. Exposures were: 1) placental abruption, 2) preterm preeclampsia (<34 weeks of gestation), 3) preeclampsia combined with infant being small for gestational age (SGA) at birth, and 4) spontaneous preterm birth. The outcome was an ID diagnosis after 3 years of age. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for each syndrome using Cox regression and robust variances. There were 9,451 children with ID (5.5 per 10,000 child-years). ID incidence rates increased with placental abruption (HR = 2.8, 95% CI: 2.3, 3.5), preterm preeclampsia (HR = 3.7, 95% CI: 2.9, 4.7), preeclampsia combined with SGA (HR = 3.3, 95% CI: 2.6, 4.1), and spontaneous preterm birth (for 32-36 and 22-31 weeks, respectively, HR = 1.6 (95% CI: 1.4, 1.8) and 5.2 (95% CI: 4.3, 6.2)). The same pattern of results was evident in sibling-controlled analyses among 1,043,158 full siblings. The strength of associations increased with ID severity. Preterm birth only partly explained the associations of placental abruption, preeclampsia, or SGA with ID. We conclude that defective placentation is related to increased incidence of ID in the offspring.

A Meta-Analysis of the Effect of Iodine Excess on the Intellectual Development of Children in Areas with High Iodine Levels in their Drinking Water

The purpose of this meta-analysis is to comprehensively investigate the effect of iodine excess on children's intellectual development in areas with high iodine levels in their drinking water. We systematically searched the electronic databases and identified 17 publications (16 in Chinese and 1 in English) on the effect of iodine excess on children's intelligence published between January 31, 1985, and January 31, 2020. This meta-analysis included 14,794 children from 28 studies. The results showed that compared with the control group, the intelligence level of children in the high iodine group reduced significantly by 1.64 points (WMD=-1.64; 95% CI (-3.225, -0.049), Z=2.02, P<0.05). Subgroup analyses were performed according to the water iodine concentration, water iodine concentration of the control group, the intelligence test method, and regions of China (i.e., north and south). We noted that when the water iodine concentration was <300μg/L, 301-600μg/L, 600.1-900μg/L, and >900μg/L, the intelligence level of the high iodine groups decreased by varying degrees, although not statistically significant (all P>0.05). The water iodine concentration of the control group was divided into two groups (<150 μg/L and <100 μg/L) and the heterogeneity analysis showed that the heterogeneity of the control group decreased significantly when the concentration of water iodine was <150 μg/L, I² = 67.3%, P<0.001, which indicated a potential source of heterogeneity. The analyses by test method showed that among the studies which used the China Joint Raven's test, the intelligence level of children in the high iodine group was 0.86 points lower than in the control group (P>0.05). Conversely, we observed that among the studies which used the China Binet intelligence test and the binaphthalene intelligence test of Tanzhida in Japan to evaluate children's intelligence level, the intelligence level of children in the high iodine groups was significantly lower (3.65 points and 8.0 points, respectively) compared with the control groups (P<0.05). The analysis of the regions of China demonstrated that whereas the reduction in children's intelligence level from excess iodine in the north of China was not statistically significant (WMD=-0.16, 95% CI (-2.18, 1.85), P>0.05), the association was statistically significant in the southern part of China (WMD=-1.86, 95% CI (-3.57, -0.09), P<0.05). This study found that high iodine concentration was statistically significantly associated with a decline in intelligence level in children. Comparatively, the intelligence level of children who were exposed to high iodine concentrations reduced significantly by 1.64 points. These findings have public health implications.

Analysis of global prevalence of mental and substance use disorders within countries: focus on sociodemographic characteristics and income levels

This report presents the prevalence of mental and substance use disorders around the world discussing the impact of geographical, sociodemographic, and income characteristics on national epidemiological differences. We analysed data from the Institute of Health Metrics and Evaluation database published in 2019. The global prevalence of mental disorders was 13.0%, with higher prevalence of anxiety disorders rate (4.1%), followed by depressive disorders (3.8%, including major depressive disorder 2.49% and dysthymia 1.35%), intellectual disability (1.5%), ADHD (1.1%), conduct disorders (0.5%), bipolar disorders (0.5%), autism spectrum disorder s (0.4%), schizophrenia (0.3%), and eating disorders (0.2%, including bulimia nervosa 0.13% and anorexia nervosa 0.05%). The worldwide prevalence of substance-use disorders was 2.2%, not surprisingly, with higher prevalence of alcohol-use disorders (1.5%) than other drug-use disorders (0.8% total including: cannabis 0.32%; opioid 0.29%, amphetamine 0.10%; cocaine 0.06%). In general, high-income countries reported higher levels of mental and substance use disorders, with the exceptions of conduct and depressive disorders (no significant differences were found among low- and high-income countries), and intellectual disability (with higher prevalence in low-income countries). In regions of the America's prevalence rates of mental and substance use disorders were higher than in Europe. Western Pacific countries reported high levels of schizophrenia, and depressive disorders were highly prevalent in Africa as well as in the Americas. Intellectual disability reported higher rates in Eastern Mediterranean and South-East Asia. We discuss the cross-cultural variations in mental health expenditure and literacy as well as stigma-related factors and some of the environmental risk factors possibly related to these prevalence differences.

A systematic review of the biological, social, and environmental determinants of intellectual disability in children and adolescents

AIM

This systematic review aimed to identify the most important social, environmental, biological, and/or genetic risk factors for intellectual disability (ID).

METHODS

Eligible were published prospective or retrospective comparative studies investigating risk factors for ID in children 4-18 years. Exclusions were single group studies with no comparator without ID and a sample size <100. Electronic databases (Medline, Cochrane Library, EMBASE, PsycInfo, Campbell Collaboration, and CINAHL) were searched for eligible publications from 1980 to 2020. Joanna Briggs Institute critical appraisal instruments, appropriate for study type, were used to assess study quality and risk of bias. Descriptive characteristics and individual study results were presented followed by the synthesis for individual risk factors, also assessed using GRADE.

RESULTS

Fifty-eight individual eligible studies were grouped into six exposure topics: sociodemographic; antenatal and perinatal; maternal physical health; maternal mental health; environmental; genetic or biological studies. There were few eligible genetic studies. For half the topics, the certainty of evidence (GRADE) was moderate or high.

CONCLUSION

Multiple studies have examined individual potential determinants of ID, but few have investigated holistically to identify those populations most at risk. Our review would indicate that there are vulnerable groups where risk factors we identified, such as low socioeconomic status, minority ethnicity, teenage motherhood, maternal mental illness, and alcohol abuse, may cluster, highlighting a target for preventive strategies. At-risk populations need to be identified and monitored so that interventions can be implemented when appropriate, at preconception, during pregnancy, or after birth. This could reduce the likelihood of ID and provide optimal opportunities for vulnerable infants.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=120032], identifier [CRD42019120032].

Maternal and Neonatal Risk Factors Affecting the Occurrence of Neurodevelopmental Disorders: A Population-Based Nationwide Study

To investigate the maternal and neonatal risk factors related to pregnancy and birth affecting the occurrence of neurodevelopmental disorders to their children using the medical claim data for the whole population. The study was conducted on all the babies born in Korea from 2005 to 2009 based on data from the National Health Information Database. All birth records were tracked from birth to December 31, 2015. To analyze factors related to the mother, data related to the mother of the newborn were collected. Increased maternal age was found to increase the risk of cerebral palsy (adjusted odds ratio [aOR] = 1.46, 95% confidence interval [CI] [1.22, 1.75]) and autism spectrum disorder (aOR = 1.48, 95% CI [1.25, 1.76]), while lowering the risk of intellectual disability (aOR = 1.83, 95% CI [1.33, 2.53]) and speech and language impairment (aOR = 1.41, 95% CI [1.08, 1.83]) compared with the reference group aged 25 to 29 years old. The incidence affected by socioeconomic factors varied according to the types of disorders. Among various risk factors, prematurity or low birth weight, problems associated with amniotic fluid or amniotic membrane, preeclampsia or eclampsia, and cesarean section affect the incidence of neurodevelopmental disorders. To reduce the incidence or severity of neurodevelopmental disorders, a better understanding of the risk factors of neurodevelopmental disorders is important. The results of this study can be used as basic data to help such understanding.

Co-occurrence of preconception maternal childhood adversity and opioid use during pregnancy: Implications for offspring brain development

Understanding of the effects of in utero opioid exposure on neurodevelopment is a priority given the recent dramatic increase in opioid use among pregnant individuals. However, opioid abuse does not occur in isolation-pregnant individuals abusing opioids often have a significant history of adverse experiences in childhood, among other co-occurring factors. Understanding the specific pathways in which these frequently co-occurring factors may interact and cumulatively influence offspring brain development in utero represents a priority for future research in this area. We highlight maternal history of childhood adversity (CA) as one such co-occurring factor that is more prevalent among individuals using opioids during pregnancy and which is increasingly shown to affect offspring neurodevelopment through mechanisms beginning in utero. Despite the high incidence of CA history in pregnant individuals using opioids, we understand very little about the effects of comorbid prenatal opioid exposure and maternal CA history on fetal brain development. Here, we first provide an overview of current knowledge regarding effects of opioid exposure and maternal CA on offspring neurodevelopment that may occur during gestation. We then outline potential mechanistic pathways through which these factors might have interactive and cumulative influences on offspring neurodevelopment as a foundation for future research in this area.

Association of maternal body mass index with intellectual disability risk

OBJECTIVES

The study aimed to investigate the association between maternal body mass index (BMI) in early pregnancy and children's intellectual disability (ID) risk in the absence of chromosomal disorders, neurofibromatosis and tuberous sclerosis, taking adverse birth outcomes, maternal hypertension/diabetes and maternal socioeconomic status into consideration.

METHODS

We conducted a cohort study of singletons without common genetic defects born in Sweden during 1992-2006, and followed them from birth until 31 December 2014 (n=1 186 836). Cox proportional hazards models were used to analyse the association between maternal BMI in early pregnancy and the risk of offspring's ID.

RESULTS

The risk of ID was higher in children born to mothers who were underweight (HR=1.21, 95% CI=1.07 to 1.36), overweight (HR=1.28, 95% CI=1.21 to 1.34) or had obesity class I (HR=1.63, 95% CI=1.53 to 1.74), obesity class II (HR=2.08, 95% CI=1.88 to 2.30) and obesity class III (HR=2.31, 95% CI=1.46 to 3.65) than in children born to normal weight mothers. Results remained consistent after excluding children with adverse birth outcome or born to mothers with gestational hypertension/diabetes. Analysis stratified by maternal education and annual household income showed that the association between maternal underweight and children's ID risk was attenuated among children of mothers with tertiary education or with high income.

CONCLUSIONS

Our findings suggest that maternal underweight or overweight/obesity in early pregnancy was associated with the development of ID in their offspring. This association was independent of the effect of adverse birth outcomes and maternal hypertension/diabetes. High socioeconomic status may attenuate the risk of ID among children of underweight mothers. This study highlights the importance of improving health education before conception to reduce children's ID risk.

Age of walking and intellectual ability in autism spectrum disorder and other neurodevelopmental disorders: a population-based study

BACKGROUND

Delayed walking is common in intellectual disability (ID) but may be less common when ID occurs with autism spectrum disorder (ASD). Previous studies examining this were limited by reliance on clinical samples and exclusion of children with severe motor deficits.

OBJECTIVE

To examine in a population-based sample if age of walking is differentially related to intellectual ability in children with ASD versus other neurodevelopmental disorders (NDD).

METHODS

Participants were from the nested Autism Birth Cohort Study of the Norwegian Mother, Father and Child Cohort Study (MoBa). Cox proportional hazards regression assessed if diagnosis (ASD n = 212 vs. NDD n = 354), continuous nonverbal IQ, and their interaction, were associated with continuous age of walking.

RESULTS

The relationship between nonverbal IQ and age of walking was stronger for NDD than for ASD (Group × nonverbal IQ interaction, χ²  = 13.93, p = .0002). This interaction was characterized by a 21% decrease in the likelihood of walking onset at any given time during the observation period per 10-point decrease in nonverbal IQ (hazard ratio = 0.79, 95% CI: 0.78-0.85) in the NDD group compared to 8% (hazard ratio = 0.92, 95% CI: 0.86-0.98) in the ASD group.

CONCLUSIONS

The finding that age of walking is less strongly related to low intellectual ability in children with ASD than in children without other NDDs supports the hypothesis that ID in ASD may result from heterogeneous developmental pathways. Late walking may be a useful stratification variable in etiological research focused on ASD and other NDDs.

Association of maternal gestational weight gain with intellectual developmental disorder in the offspring: a nationwide follow-up study in Sweden

OBJECTIVES

To investigate the association between maternal gestational weight gain (GWG) and offspring's intellectual developmental disorders (IDD); how this association is modified by maternal early-pregnancy BMI.

DESIGN

Population-based cohort study.

SETTING AND POPULATION

All liveborn singletons with information on maternal GWG in the Swedish Medical Register during 1992-2006 (n = 467 485).

METHODS

We used three GWG classifications, (1) Institute of Medicine (IOM) guidelines ('ideal' GWG: maternal underweight = 12.7-18.1 kg; normal = 11.3-15.9 kg; overweight = 6.8-11.3 kg; obesity = 5.0-9.1 kg), (2) LifeCycle project recommendation ('ideal' GWG: maternal underweight = 14.0-16.0 kg; normal = 10.0-18.0 kg; overweight = 2.0-16.0 kg; obesity class I = 2.0-6.0 kg; obesity class II ≤0.0-4.0 kg; obesity class III ≤0.0-6.0 kg) and (3) GWG centiles. Hazard ratio (HR) and 95% CI for offspring's IDD risk using Cox regression.

MAIN OUTCOME MEASURES

IDD was extracted from Swedish National Patient Register (code ICD-9:317-319/ICD-10:F70-F79).

RESULTS

Forty-one per cent of children were born to mothers with excessive GWG, 32.8% with ideal GWG and 26.2% with inadequate GWG according to IOM guidelines. Inadequate GWG was associated with 21% higher risk of offspring's IDD (95% CI 1.11-1.31) relative to ideal GWG. In contrast, when using the LifeCycle classification, children of mothers with inadequate GWG (HR 1.14, 95% CI 1.05-1.24) or excessive GWG (HR 1.09, 95% CI 1.01-1.17) had higher risks of IDD than those of mothers with ideal GWG. When using GWG centiles, extremely low GWG (<20th centile) and low GWG (20th-40th centile) were associated with elevated offspring's IDD risk. Further stratified analysis by maternal early-pregnancy body mass index (BMI) showed that overweight/obese mothers (BMI ≥25 kg/m² ) with extremely excessive GWG (>25 kg) was associated with an increased offspring's IDD.

CONCLUSION

Our findings suggest that inadequate maternal GWG may increase offspring's IDD risk, irrespective of maternal early-pregnancy BMI. Extremely excessive GWG (>25 kg) may increase offspring's IDD risk, but only among mothers with an early-pregnancy BMI ≥25 kg/m² .

TWEETABLE ABSTRACT

Inadequate maternal weight gain during pregnancy may increase the risk of offspring's intellectual disability, regardless of maternal BMI.

Prevalence of intellectual disability among eight-year-old children from selected communities in the United States, 2014

BACKGROUND

Children with intellectual disability (ID), characterized by impairments in intellectual functioning and adaptive behavior, benefit from early identification and access to services. Previous U.S. estimates used administrative data or parent report with limited information for demographic subgroups.

OBJECTIVE

Using empiric measures we examined ID characteristics among 8-year-old children and estimated prevalence by sex, race/ethnicity, geographic area and socioeconomic status (SES) area indicators.

METHODS

We analyzed data for 8-year-old children in 9 geographic areas participating in the 2014 Autism and Developmental Disabilities Monitoring Network. Children with ID were identified through record review of IQ test data. Census and American Community Survey data were used to estimate the denominator.

RESULTS

Overall, 11.8 per 1,000 (1.2%) had ID (IQ ≤ 70), of whom 39% (n = 998) also had autism spectrum disorder. Among children with ID, 1,823 had adaptive behavior test scores for which 64% were characterized as impaired. ID prevalence per 1,000 was 15.8 (95% confidence interval [95% CI], 15.0-16.5) among males and 7.7 (95% CI, 7.2-8.2) among females. ID prevalence was 17.7 (95% CI, 16.6-18.9) among children who were non-Hispanic black; 12.0 (95% CI, 11.1-13.0), among Hispanic; 8.6 (95% CI, 7.1-10.4), among non-Hispanic Asian; and 8.0 (95% CI, 7.5-8.6), among non-Hispanic white. Prevalence varied across geographic areas and was inversely associated with SES.

CONCLUSIONS

ID prevalence varied substantively among racial, ethnic, geographic, and SES groups. Results can inform strategies to enhance identification and improve access to services particularly for children who are minorities or living in areas with lower SES.

Comprehensive Assessment of Individuals With Significant Levels of Intellectual Disability: Challenges, Strategies, and Future Directions

The variety and extent of impairments in individuals with severe-profound levels of intellectual disability (ID) impact their ability to complete valid behavioral assessments. Although standardized assessment is crucial for objectively evaluating patients, many individuals with severe-profound levels of ID perform at the floor of most assessments designed for their chronological age. Additionally, the presence of language and motor impairments may influence the individual's ability to perform a task, even when that task is meant to measure an unrelated construct leading to an underestimation of their true ability. This article provides an overview of the assessment protocols used by multiple groups working with individuals with severe-profound levels of ID, discusses considerations for obtaining high-quality assessment results, and suggests guidelines for standardizing these protocols across the field.

Head circumference at birth and intellectual disability: a nationwide cohort study

BACKGROUND

Intellectual disability (ID) is a prevalent chronic disability affecting up to 1-3% of the general population. Small head circumference at birth, a surrogate measure of foetal cerebral growth, may be a risk factor for ID. We aimed to investigate the association between the full distribution of head circumference at birth and ID.

METHODS

This cohort study was based on Danish nationwide registries and included all Danish singletons born alive from 1997 to 2013. Follow-up ended at October 2015. The data was analysed using a Cox proportional hazards regression model adjusted for a large number of potential confounders.

RESULTS

The cohort comprised 986,909 infants. Neither microcephaly nor macrocephaly at birth was consistently associated with the risk of ID. Within the normal range of head circumference, larger head circumference was associated with a decreased risk of ID (HR per standard deviation increase in head circumference z score 0.85, 95% CI 0.81-0.88). The association detected within the normal range was consistent in all sensitivity analyses.

CONCLUSIONS

Intrauterine brain growth restriction may be a risk factor for ID.

Association of Cesarean Delivery With Risk of Neurodevelopmental and Psychiatric Disorders in the Offspring: A Systematic Review and Meta-analysis

Importance

Birth by cesarean delivery is increasing globally, particularly cesarean deliveries without medical indication. Children born via cesarean delivery may have an increased risk of negative health outcomes, but the evidence for psychiatric disorders is incomplete.

Objective

To evaluate the association between cesarean delivery and risk of neurodevelopmental and psychiatric disorders in the offspring.

Data Sources

Ovid MEDLINE, Embase, Web of Science, and PsycINFO were searched from inception to December 19, 2018. Search terms included all main mental disorders in the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition).

Study Selection

Two researchers independently selected observational studies that examined the association between cesarean delivery and neurodevelopmental and psychiatric disorders in the offspring.

Data Extraction and Synthesis

Two researchers independently extracted data according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines and assessed study quality using the Newcastle-Ottawa Scale. Random-effects meta-analyses were used to pool odds ratios (ORs) with 95% CIs for each outcome. Sensitivity and influence analyses tested the robustness of the results.

Main Outcomes and Measures

The ORs for the offspring with any neurodevelopmental or psychiatric disorder who were born via cesarean delivery compared with those were born via vaginal delivery.

Results

A total of 6953 articles were identified, of which 61 studies comprising 67 independent samples were included, totaling 20 607 935 deliveries. Compared with offspring born by vaginal delivery, offspring born via cesarean delivery had increased odds of autism spectrum disorders (OR, 1.33; 95% CI, 1.25-1.41; I2 = 69.5%) and attention-deficit/hyperactivity disorder (OR, 1.17; 95% CI, 1.07-1.26; I2 = 79.2%). Estimates were less precise for intellectual disabilities (OR, 1.83; 95% CI, 0.90-3.70; I2 = 88.2%), obsessive-compulsive disorder (OR, 1.49; 95% CI, 0.87-2.56; I2 = 67.3%), tic disorders (OR, 1.31; 95% CI, 0.98-1.76; I2 = 75.6%), and eating disorders (OR, 1.18; 95% CI, 0.96-1.47; I2 = 92.7%). No significant associations were found with depression/affective psychoses or nonaffective psychoses. Estimates were comparable for emergency and elective cesarean delivery. Study quality was high for 82% of the cohort studies and 50% of the case-control studies.

Conclusions and Relevance

The findings suggest that cesarean delivery births are associated with an increased risk of autism spectrum disorder and attention-deficit/hyperactivity disorder, irrespective of cesarean delivery modality, compared with vaginal delivery. Future studies on the mechanisms behind these associations appear to be warranted.

Psychiatric symptoms in men with hypospadias - preliminary results of a cross-sectional cohort study

AIM

Population studies have shown an increased risk of neurodevelopmental disorders in males born with the congenital condition hypospadias, where the opening of the urethra is on the underside of the penis. We investigated overall psychiatric morbidity in cases and matched controls.

METHODS

This study compared 167 men born with hypospadias from 1959 to 1994 in Stockholm or Gothenburg in Sweden using hospital registers. They were compared with controls from the Swedish population registry, who were contacted by regular mail and students who were recruited by local advertisements. The total sample had a mean age of 33.5 years (range: 19-54). They completed self-rating scales for depressive, anxiety and obsessive-compulsive symptoms and symptoms of attention deficit hyperactivity disorder. In addition, 33 cases and 47 controls underwent psychiatric morbidity interviews that covered the 17 most common psychiatric diagnoses.

RESULTS

A fifth (21%) of both the cases and controls reported current or previous psychiatric symptoms. There were no significant differences in self-rated depression, anxiety or obsessive-compulsive disorder symptoms between the patients and controls or between the different phenotype groups. The distribution was not significantly affected by the severity of hypospadias.

CONCLUSION

Psychiatric morbidity was no higher in men with hypospadias than population-based controls.

Neuroanatomical Correlates of Advanced Paternal and Maternal Age at Birth in Autism Spectrum Disorder

Although advanced paternal and maternal age at birth (PA/MA) increases the risk of autism spectrum disorder (ASD), the underlying neurobiological mechanisms are not fully understood. To explore the neuroanatomical correlates of advanced PA/MA, the current study conducted brain morphometric analyses in 39 high-functioning adult males with ASD and 39 age-, intellectual level-, and parental socioeconomic background-matched, typically developed (TD) males. Whole-brain analysis revealed that the regional gray matter volume (GMV) in bilateral posterior cingulate cortex (PCC) and precuneus (PCU) were significantly smaller in the individuals with ASD than in TD subjects (false discovery rate-corrected P = 0.014). Additional analyses of the constituents of GMV reduction in these brain regions revealed that the cortical thickness of the right ventral PCC was significantly thinner (P = 0.014) and the surface area of bilateral PCU was significantly smaller (left: P = 0.001; right: P = 0.049) in the adults with ASD, compared with TD subjects. Although the analyses were exploratory, the thinner cortical thickness of right ventral PCC was significantly correlated with older PA in the ASD individuals (P = 0.028). The current findings shed new light on the neurobiological mechanisms underlying the link between advanced PA and ASD.

Predictive validity of developmental milestones for detecting limited intellectual functioning

Developmental milestones are commonly used in child health care, although from many milestones the predictive validity has not been adequately assessed. We aimed to determine the predictive validity of 75 developmental milestones for detecting limited intellectual functioning that can be obtained before the age of 4 years. We performed a case-control study with 148 children aged 5–10 years with limited intellectual functioning (IQ 50–69), who were in special education (cases) and a random sample of 300 children aged 5–10 years who were in regular elementary education (controls). Developmental milestones scores were retrieved from Child Healthcare files. We calculated sensitivity, specificity, positive likelihood ratios (LR+) and diagnostic odds ratios (DOR) for limited intellectual functioning. The LR+ determines whether a test result changes the probability that a condition exists. Given the prevalence of intellectual disability (1–3%), we considered that an LR+ > 10 would be clinically useful, as it increases the a priori probability of limited intellectual functioning from 2% to a posteriori probability of at least 17%. Out of 75 assessed milestones, 50 were included in the analysis. We found nine milestones to have a significant adjusted (for socio-economic status and prematurity) DOR > 1 and a significant LR+ > 10 (assessment age in months between brackets): ‘says "dada-baba‴ (9), ‘balances head well while sitting’ (9), ‘sits on buttocks while legs stretched’ (9), ‘babbles while playing’ (12), ‘sits in stable position without support’ (12), ‘walks well alone’ (24), ‘says "sentences" of 3 or more words’ (36), ‘places 3 forms in form-box’ (36) and ‘copies circle’ (48). Sensitivities of these 9 milestones varied from 8–54%, specificities of these 9 milestones varied from 95–100%. Combining these milestones at 9, 12, and 36 months respectively resulted in sensitivities of 27–60% and specificities of 94–99%. These nine developmental milestones have substantial predictive validity for limited intellectual functioning.

Risk Factors for Preoperative Developmental Delay in Patients with Nonsyndromic Sagittal Craniosynostosis

BACKGROUND

Some patients with isolated sagittal craniosynostosis have demonstrated mild neurodevelopmental delays. This study examined potential preoperative risk factors for developmental delay.

METHODS

Patients completed preoperative Bayley Scales of Infant and Toddler Development, Third Edition, and medical records were reviewed. Multivariate analyses of covariance and correlations were calculated.

RESULTS

Participants (n = 77) were predominantly male (77.9 percent) and were aged 2 to 12 months (mean, 5.1 ± 2.3 months). Patients were classified with no delays [n = 63 (82 percent)] or delays [n = 14 (18 percent)] in one or more developmental area(s). There were no group sociodemographic differences. Prenatally, patients with delays versus no delays had lower mean gestational age in weeks (36.9 ± 2.8 weeks versus 39.1 ± 1.7 weeks; p = 0.001) with higher rates of gestational diabetes (36 percent versus 5 percent; p = 0.006) and premature rupture of membranes (14 percent versus 2 percent; p = 0.026). At birth, patients with delays had lower mean birth weight (2982 ± 714 g versus 3374 ± 544 g; p = 0.053), higher rates of respiratory distress (29 percent versus 5 percent; p = 0.005), additional medical diagnoses (57 percent versus 13 percent; p = 0.001), and longer mean neonatal intensive care unit stays (1.4 ± 1.8 weeks versus 0.2 ± 0.9 week; p = 0.002). Variables differing by group had moderate correlations.

CONCLUSIONS

Patients with nonsyndromic sagittal craniosynostosis that had delays in development had lower gestational age and birth weight, with more prenatal and birth complications. These factors can help identify patients who might be at risk for delay and need close monitoring.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Apgar score and risk of autism

Low Apgar score has been associated with higher risk for several neurological and psychiatric disorders, including cerebral palsy and intellectual disability. Studies of the association between Apgar score and autism spectrum disorder (ASD) have been inconsistent. We aimed to investigate (1) the association between low Apgar score at 5 min and risk for ASD, and (2) the modifying effects of gestational age and sex on this association in the largest multinational database of ASD. We included prospective data from 5.5 million individuals and over 33,000 cases of ASD from Norway, Sweden, Denmark and Western Australia who were born between 1984 and 2007. We calculated crude and adjusted risk ratios (RR) with 95% confidence intervals (95% CIs) for the associations between low Apgar score and ASD. All analyses for ASD were repeated for autistic disorder (AD). We used interaction terms and stratified analysis to investigate the effects of sex, gestational age, and birth weight on the association. In fully adjusted models, low Apgar scores (1-3) (RR, 1.42; 95% CI, 1.16-1.74), and intermediate Apgar scores (4-6) (RR, 1.50; 95% CI, 1.36-1.65) were associated with a higher RR of ASD than optimal Apgar score (7-10). The point estimates for low (RR, 1.88; 95% CI, 1.41-2.51) and intermediate Apgar score (RR, 1.54; 95% CI, 1.32-1.81) were larger for AD than for ASD. This study suggests that low Apgar score is associated with higher risk of ASD, and in particular AD. We did not observe any major modifying effects of gestational age and sex, although there seems to be substantial confounding by gestational age and birth weight on the observed association.

Autism Spectrum Disorder and Neonatal Serum Magnesium Levels in Preterm Infants

Premature birth is associated with increased risk of autism spectrum disorder. Antenatal maternal magnesium administration is known to reduce subsequent risk of cerebral palsy including among premature infants, suggesting a potentially broader neuroprotective role for magnesium. Our objective was to determine whether magnesium could be protective against autism spectrum disorders in premature infants. A cohort of 4855 preterm children was identified, magnesium levels from 24 to 48 hours of life recorded, and subsequent autism spectrum disorder status determined. Adjusted relative risk of autism spectrum disorder with each 1 mg/dL increase in neonatal magnesium level was 1.15 (95% confidence interval: 0.86-1.53). Analysis of variance indicated that magnesium levels varied by gestational age and maternal antenatal magnesium supplementation, but not autism spectrum disorder status (F_1,4824 = 1.43, P = .23). We found that neonatal magnesium levels were not associated with decreased autism spectrum disorder risk. Future research into autism spectrum disorder risks and treatments in premature infants is needed.

Low Apgar scores at both one and five minutes are associated with long-term neurological morbidity

AIM

This study evaluated the associations between low Apgar scores at one and five minutes and long-term neurological impairments.

METHODS

This study used population-based data on 399,815 singletons born in Finland in 2004-2010 and multivariable logistic regression to examine any associations between low (0-3) and intermediate (4-6) Apgar scores and cerebral palsy, epilepsy, intellectual disability and sensorineural defects by the age of four years.

RESULTS

The odd ratios (OR) and 95% confidence intervals (95% CI) showed that low Apgar scores were associated with cerebral palsy at one and five minutes (ORs 2.08, 95% CI 1.32-3.26 and 5.19, 95% CI 3.06-8.80), epilepsy (ORs 1.62, 95% CI 1.13-2.33 and 4.79, 95% CI 3.03-7.56), and intellectual disability (ORs 2.46, 95% CI 1.45-4.16 and 6.21, 95% CI 3.33-11.58). Only a low five-minute Apgar score was associated with sensorineural defects (OR 3.13, 95% CI 1.95-5.02). Neurological impairment risks were increased by low Apgar scores at both one and five minutes (OR 11.1, 95% CI 8.6-14.5), but 90.3% of children with persistent low Apgar scores had no impairment.

CONCLUSION

Low one-minute and five-minute Apgar scores were associated with long-term neurological morbidity, especially when both scores were low.

Risk Factors Associated with Severity of Nongenetic Intellectual Disability (Mental Retardation) among Children Aged 2-18 Years Attending Kenyatta National Hospital

Background

Many of the nongenetic causal risk factors of intellectual disability (ID) can be prevented if they are identified early. There is paucity on information regarding potential risk factors associated with this condition in Kenya. This study aimed to establish risk factors associated with severity of nongenetic intellectual disability (ID) among children presenting with this condition at Kenyatta National Hospital (KNH).

Methods

A hospital-based cross-sectional study was conducted over the period between March and June 2017 in pediatric and child/youth mental health departments of Kenyatta National Hospital (KNH), Kenya. It included children aged 2–18 years diagnosed with ID without underlying known genetic cause.

Results

Of 97 patients with nongenetic ID, 24% had mild ID, 40% moderate, 23% severe-profound, and 10% unspecified ID. The mean age of children was 5.6 (±3.6) years. Male children were predominant (62%). Three independent factors including “labor complications” [AOR = 9.45, 95% CI = 1.23–113.29, P = 0.036], “admission to neonatal intensive care unit” [AOR = 8.09, 95% CI = 2.11–31.07, P = 0.002], and “cerebral palsy” [AOR = 21.18, CI = 4.18–107.40, P ≤ 0.001] were significantly associated with increased risk of severe/profound nongenetic ID.

Conclusion

The present study findings suggest that perinatal complications as well as postnatal insults are associated with increased risk of developing severe-profound intellectual disability, implying that this occurrence may be reduced with appropriate antenatal, perinatal, and neonatal healthcare interventions.

Childhood Health Outcomes in Term, Large-for-Gestational-Age Babies With Different Postnatal Growth Patterns

Large-for-gestational-age (LGA) babies have a higher risk of metabolic disease later in life, and their postnatal growth in early childhood may be associated with long-term adverse outcomes. This study aimed to determine childhood health outcomes of term LGA babies with different growth patterns. Data were obtained from the US Collaborative Perinatal Project for the years between 1959 and 1976. The growth trajectories of 3,316 term LGA babies were identified and odds ratios of obesity, growth restriction, low intelligence quotient (IQ), and high blood pressure (HBP) were calculated by logistic regression. Compared with term appropriate-for-gestational-age infants, term LGA babies without catch-down growth had increased risks of obesity (adjusted odds ratio (aOR) = 6.37, 95% confidence interval (CI): 5.24, 7.73) and HBP (aOR = 1.67, 95% CI: 1.37, 2.03). Those with high catch-down growth had higher risks of growth restriction (aOR = 2.21, 95% CI: 1.66, 2.95) and low IQ (aOR = 1.61, 95% CI: 1.04, 2.49). Nevertheless, infants with small catch-down growth had lower risks of obesity (aOR = 0.78, 95% CI: 0.63, 0.95), growth restriction (aOR = 0.28, 95% CI: 0.17, 0.46), low IQ (aOR = 0.66, 95% CI: 0.41, 1.06), and HBP (aOR = 0.89, 95% CI: 0.77, 1.04). According to our data, term LGA infants with small catch-down growth had no increased risks of adverse outcomes.

Intellectual disability in children aged less than seven years born moderately and late preterm compared with very preterm and term-born children - a nationwide birth cohort study

BACKGROUND

Prematurity has been shown to be associated with an increased risk of intellectual disability (ID).

METHOD

The aim was to establish whether the prevalence of ID, defined as significant limitations in both intellectual (intelligence quotient below 70) and adaptive functioning among moderately preterm (MP; 32⁺⁰ -33⁺⁶  weeks) and late preterm (LP; 34⁺⁰ -36⁺⁶  weeks) infants, is increased compared with that in term infants (≥37⁺⁰  weeks). Antenatal and neonatal risk factors for ID among gestational age groups were sought. The national register study included all live-born infants in Finland in 1991-2008, excluding those who died before one year age, or had any major congenital anomaly or missing data. A total of 1 018 256 infants (98.0%) were analysed: very preterm (VP; <32⁺⁰  weeks, n = 6329), MP (n = 6796), LP (n = 39 928) and term (n = 965 203).

RESULTS

By the age of seven years, the prevalence of ID was 2.48% in the VP group, 0.81% in the MP group, 0.55% in the LP group and 0.35% in the term group. Intracranial haemorrhage increased the ID risk in all groups. Male sex and born small for gestational age predicted an increased risk in all but the MP group.

CONCLUSIONS

The prevalence of ID decreased with increasing gestational age. Prevention of intracranial haemorrhages may have a beneficial effect on the neurodevelopmental outcomes of neonates.

Are Major Depression and Generalized Anxiety Disorder Associated With Oligohydramnios in Pregnant Women? A Case-Control Study

PURPOSE

This study examined the prevalence of major depression and generalized anxiety disorder (GAD) in pregnant women with and without a diagnosis of oligohydramnios.

DESIGN AND METHODS

The study sample included 53 pregnant women with a diagnosis of oligohydramnios and 80 healthy pregnant women subjects. Major depression and GAD were diagnosed with the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (SCID-I).

FINDINGS

Pregnant women with oligohydramnios had higher scores of depressive and anxiety symptom, and a higher prevalence rate of major depression (24.5% vs. 6.2%) and GAD (30.2% vs. 3.2%).

PRACTICE IMPLICATIONS

The results of the present study suggest that oligohydramnios appears to be associated with both major depression and GAD in pregnant women.

Do children born to teenage parents have lower adult intelligence? A prospective birth cohort study

Teenage motherhood has been associated with a wide variety of negative offspring outcomes including poorer cognitive development. In the context of limitations of previous research, this paper assesses the contemporary relevance of this finding. In this study we investigate the long-term cognitive status (IQ) among 21 year adult offspring born to teenage parents using the Mater University Study of Pregnancy- a prospective birth cohort study, which recruited all pregnant mothers attending a large obstetrical hospital in Brisbane, Australia, from 1981 to 1983. The analyses were restricted to a sub-sample of 2643 mother-offspring pair. Offspring IQ was measured using the Peabody Picture Vocabulary Test at 21 year. Parental age was reported at first clinic visit. Offspring born to teenage mothers (<20 years) have -3.0 (95% Confidence Interval (CI): -4.3, -1.8) points lower IQ compared to children born to mothers ≥20 years and were more likely to have a low IQ (Odds Ratio (OR) 1.7; 95% CI: 1.3, 2.3). Adjustment for a range of confounding and mediating factors including parental socioeconomic status, maternal IQ, maternal smoking and binge drinking in pregnancy, birthweight, breastfeeding and parenting style attenuates the association, though the effect remains statistically significant (-1.4 IQ points; 95% CI: -2.8,-0.1). Similarly the risk of offspring having low IQ remained marginally significantly higher in those born to teenage mothers (OR 1.3; 95% CI: 1.0, 1.9). In contrast, teenage fatherhood is not associated with adult offspring IQ, when adjusted for maternal age. Although the reduction in IQ is quantitatively small, it is indicative of neurodevelopmental disadvantage experienced by the young adult offspring of teenage mothers. Our results suggest that public policy initiatives should be targeted not only at delaying childbearing in the population but also at supporting early life condition of children born to teenage mothers to minimize the risk for disadvantageous outcomes of the next generation.

Impaired Gas Exchange at Birth and Risk of Intellectual Disability and Autism: A Meta-analysis

We conducted meta-analyses of 67 studies on the association between neonatal proxies of impaired gas exchange and intellectual disability (ID) or autism spectrum disorders (ASD). Neonatal acidosis was associated with an odds ratio (OR) of 3.55 [95 % confidence interval (95 % CI) 2.23-5.49] for ID and an OR of 1.10 (95 % CI 0.91-1.31) for ASD. Children with a 5-min Apgar score of <7 had an OR of 5.39 (95 % CI 3.84-7.55) for ID and an OR of 1.67 (95 % CI 1.34-2.09) for ASD. O2 treatment was associated with an OR of 4.32 (95 % CI 3.23-5.78) for ID and an OR of 2.02 (95 % CI 1.45 to 2.83) for ASD. Our meta-analysis demonstrates an increased risk of ID and (to a lesser extent) ASD in children with neonatal hypoxia. Moreover, our findings raise the possibility that concomitant ID might account for the observed association between the gas exchange proxies and ASD.

Prenatal, Perinatal and Neonatal Risk Factors for Intellectual Disability: A Systemic Review and Meta-Analysis

BACKGROUND

The etiology of non-genetic intellectual disability (ID) is not fully known, and we aimed to identify the prenatal, perinatal and neonatal risk factors for ID.

METHOD

PubMed and Embase databases were searched for studies that examined the association between pre-, peri- and neonatal factors and ID risk (keywords "intellectual disability" or "mental retardation" or "ID" or "MR" in combination with "prenatal" or "pregnancy" or "obstetric" or "perinatal" or "neonatal". The last search was updated on September 15, 2015. Summary effect estimates (pooled odds ratios) were calculated for each risk factor using random effects models, with tests for heterogeneity and publication bias.

RESULTS

Seventeen studies with 55,344 patients and 5,723,749 control individuals were eligible for inclusion in our analysis, and 16 potential risk factors were analyzed. Ten prenatal factors (advanced maternal age, maternal black race, low maternal education, third or more parity, maternal alcohol use, maternal tobacco use, maternal diabetes, maternal hypertension, maternal epilepsy and maternal asthma), one perinatal factor (preterm birth) and two neonatal factors (male sex and low birth weight) were significantly associated with increased risk of ID.

CONCLUSION

This systemic review and meta-analysis provides a comprehensive evidence-based assessment of the risk factors for ID. Future studies are encouraged to focus on perinatal and neonatal risk factors and the combined effects of multiple factors.

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.

Cognitive impairments are different in single-incidence and multi-incidence ADHD families

BACKGROUND

We may improve our understanding of the role of common versus unique risk factors in attention-deficit/hyperactivity disorder (ADHD) by examining ADHD-related cognitive deficits in single- (SPX), and multi-incidence (MPX) families. Given that individuals from multiplex (MPX) families are likely to share genetic vulnerability for the disorder, whereas simplex (SPX) ADHD may be the result of sporadic (non-)genetic causes unique to the patient, we hypothesized that cognitive impairments may be different in SPX and MPX ADHD as indicated by (a) the presence of cognitive deficits in MPX, but not SPX unaffected siblings and (b) dissimilar cognitive profiles in SPX and MPX ADHD patients.

METHODS

Tasks measuring total IQ, verbal attention, executive functioning, motor functioning, and time estimation were administered to 31 SPX/264 MPX ADHD probands, 47 SPX/123 MPX unaffected siblings, and 263 controls, aged 6-19 years.

RESULTS

SPX unaffected siblings were unimpaired compared to controls, except for verbal working memory, whereas MPX unaffected siblings showed impairments on most cognitive domains. The cognitive profiles of SPX and MPX probands were highly similar, except that verbal attention, response inhibition and motor control deficits were more pronounced in MPX probands, and -compared to their unaffected siblings- impairments in IQ, visual working memory and timing abilities were more pronounced in SPX cases.

CONCLUSIONS

Our results support the hypothesis that a partly different cognitive architecture may underlie SPX and MPX forms of ADHD, which becomes evident when contrasting cognitive performances within families. Cognitive factors underlying MPX forms of ADHD are familial, whereas nonfamilial in SPX ADHD. SPX-MPX stratification may be a step forward in unraveling diverse causal pathways.

Hypospadias and increased risk for neurodevelopmental disorders

BACKGROUND

Hypospadias (aberrant opening of the urethra on the underside of the penis) occurs in 1 per 300 newborn boys. It has been previously unknown whether this common malformation is associated with increased psychiatric morbidity later in life. Studies of individuals with hypospadias also provide an opportunity to examine whether difference in androgen signaling is related to neurodevelopmental disorders. To elucidate the mechanisms behind a possible association, we also studied psychiatric outcomes among brothers of the hypospadias patients.

METHODS

Registry study within a national cohort of all 9,262 males with hypospadias and their 4,936 healthy brothers born in Sweden between 1973 and 2009. Patients with hypospadias and their brothers were matched with controls by year of birth and county. The following outcomes were evaluated (1) any psychiatric (2) psychotic, (3) mood, (4) anxiety, (5) eating, and (6) personality disorders, (7) substance misuse, (8) attention-deficit hyperactivity disorder (ADHD), (9) autism spectrum disorders (ASD), (10) intellectual disability, and (11) other behavioral/emotional disorders with onset in childhood.

RESULTS

Patients with hypospadias were more likely to be diagnosed with intellectual disability (OR 3.2; 95% CI 2.8-3.8), ASD (1.4; 1.2-1.7), ADHD (1.5; 1.3-1.9), and behavioral/emotional disorders (1.4; 1.2-1.6) compared with the controls. Brothers of patients with hypospadias had an increased risk of ASD (1.6; 1.3-2.1) and other behavioral/emotional disorders with onset in childhood (1.2; 0.9-1.5) in comparison to siblings of healthy individuals. A slightly higher, although not statistically significant, risk was found for intellectual disability (1.3; 1.0-1.9). No relation between other psychiatric diagnosis and hypospadias was found.

CONCLUSIONS

This is the first study to identify an increased risk for neurodevelopmental disorders in patients with hypospadias, as well as an increased risk for ASD in their brothers, suggesting a common familial (genetic and/or environmental) liability.

Association between mechanical ventilation and neurodevelopmental disorders in a nationwide cohort of extremely low birth weight infants

Mechanical ventilation for preterm infants independently contributes to poor neurodevelopmental performance. However, few studies have investigated the association between the duration of mechanical ventilation and the risk for various developmental disorders in extremely low birth weight (ELBW) (<1000g) infants. Using a large nationwide database, we did a 10-year retrospective follow-up study to explore the effect of mechanical ventilation on the incidence of cerebral palsy (CP), autism spectrum disorder (ASD), intellectual disability (ID), and attention-deficit/hyperactivity disorder (ADHD) in ELBW infants born between 1998 and 2001. Seven hundred twenty-eight ELBW infants without diagnoses of brain insults or focal brain lesions in the initial hospital stay were identified and divided into three groups (days on ventilator: ≦2, 3-14, ≧15 days). After adjusting for demographic and medical factors, the infants in the ≧15 days group had higher risks for CP (adjusted hazard ratio: 2.66; 95% confidence interval: 1.50-4.59; p<0.001) and ADHD (adjusted hazard ratio: 1.95; 95% confidence interval: 1.02-3.76; p<0.05), than did infants in the ≦2 days group. The risk for ASD or ID was not significantly different between the three groups. We conclude that mechanical ventilation for ≧15 days increased the risk for CP and ADHD in ELBW infants even without significant neonatal brain damage. Developing a brain-protective respiratory support strategy in response to real-time cerebral hemodynamic and oxygenation changes has the potential to improve neurodevelopmental outcomes in ELBW infants.