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Adverse childhood experiences (ACEs) are risk factors for mental and physical illness and more likely to occur for children with autism spectrum disorder (ASD). The present study aimed to clarify the contribution of poverty, intellectual disability and mental health conditions to this disparity. Data on child and family characteristics, mental health conditions and ACEs were analyzed in 67,067 youth from the 2011-2012 National Survey of Children's Health. In an income-stratified sample, the association of ASD and ACEs was greater for lower income children and significantly diminished after controlling for child mental health conditions, but not intellectual disability. Findings suggest that the association of ACEs and ASD is moderated by family income and contingent on co-occurring mental health conditions.

Epilepsy is reported to co-occur in individuals with autism spectrum disorder (ASD). Previous studies across the world have found prevalence estimates ranging from 4 to 38%. We examined parent-reported prevalence of co-occurring epilepsy and ASD in the most recent U.S. National Survey of Children's Health, 2011-2012. All analyses accounted for survey weights to account for the complex sampling design. In the overall analytic sample of 85,248 children ages 2-17, there were 1,604 children with ASD (prevalence of 1.8%) and 1,083 children with epilepsy (prevalence of 1.2%). Epilepsy was reported to co-occur in 8.6% of ASD cases. In children with ASD, the co-occurrence of epilepsy was associated with increasing child age, female gender, intellectual disability, speech problems and lower socioeconomic status.

Autism spectrum disorder (ASD) is highly heritable, yet how its familial risk and heritability may vary by cognitive ability is not well understood. In this population‐based cohort study, we examined the familial risk and heritability of ASD with and without co‐occurring intellectual disability (ID). We estimated odds ratios and heritability of ASD with ID (ASD+ID) and ASD without ID (ASD−ID) using register‐based diagnosis data of 567,436 index persons born in 1984–2009 in Stockholm County, Sweden, and their parents, siblings, cousins, aunts, and uncles. The familial risk profile exhibited differences between ASD−ID and ASD+ID, most notably for index persons with affected parents. For example, for an index person who had at least one parent with ASD, the child's odds of ASD−ID and ASD+ID (95% confidence interval (CI)) increased by 16.2 (14.2–18.6) and 7.4 (5.5–10.0) folds, respectively. The more closely related a family member with ASD was, the greater the observed risk was of ASD in the index person, especially for ASD−ID. The broad‐sense heritability (95% CI) for ASD − ID and ASD+ID were 64.6% (46.0–100.0%) and 33.4% (14.4–58.4%), respectively. Familial risk and heritability of ASD may vary by intellectual ability, which implies that risk factors between these ASD phenotypes may differ. Our findings from the heritability analysis and familial risk analysis suggest that ASD−ID may have a greater genetic basis than ASD+ID, although this should be verified in future studies. Lay Summary Autism spectrum disorder (ASD) is highly heritable, yet how its familial risk and heritability may vary by cognitive ability is not well‐understood. In a population‐based cohort study on families of 567,436 index persons using Swedish registers data, we found that the familial risk profile differed between ASD with and without intellectual disability. Our findings from the heritability analysis and familial risk analysis suggest that ASD−ID may have a greater genetic basis than ASD+ID, although this should be verified in future studies. [ABSTRACT FROM AUTHOR]

Background: Preterm birth has been linked to increased risk of autism spectrum disorders (ASD), but how this risk changes with gestational age at birth has not been well characterised, especially with regard to co-occurring intellectual disability (ID).Methods: Register-based cohort study of singleton births in 1984-2007 in Stockholm County, Sweden (N total: 480 728; n ASD: 10 025). We assessed overall and sex-specific, gestational week-specific prevalence estimates and risk ratios of ASD with and without ID.Results: Preterm and postterm births were associated with elevated risk of ASD, and the relationship between gestational age at birth and ASD with and without ID differed in males and females. Risk of ASD without ID was higher in preterm births among both sexes and decreased continuously with increasing length of gestation. Risk of ASD with ID was higher in both preterm and postterm births among both sexes, with postterm birth in females being more highly associated with ASD with ID than that in males.Conclusions: The relationship between gestational age at birth and ASD differs by the presence/absence of co-occurring ID and fetal sex. Both preterm and postterm birth are associated with increased risk of ASD. Risk of ASD is not constant within conventionally defined gestational age at birth periods. Further research on mechanism underlying these associations is needed. [ABSTRACT FROM AUTHOR]

Background: The objectives of this study were to examine the independent and dependent associations of maternal and paternal age and risk of offspring autism spectrum disorders (ASD), with and without intellectual disability (ID).Methods: The sample consisted of 417 303 Swedish children born 1984–2003. ASD case status (N = 4746) was ascertained using national and regional registers. Smoothing splines in generalized additive models were used to estimate associations of parental age with ASD.Results: Whereas advancing parental age increased the risk of child ASD, maternal age effects were non-linear and paternal age effects were linear. Compared with mothers at the median age 29 years, those <29 had similar risk, whereas risk increased after age 30, with an odds ratio (OR) of 1.75 [95% (CI): 1.63–1.89] at ages 40–45. For fathers, compared with the median age of 32 years, the OR for ages 55–59 was 1.39 (1.29–1.50). The risk of ASD was greater for older mothers as compared with older fathers. For example, mothers aged 40–45 (&geq;97.2th percentile) had an estimated 18.63 (95% CI: 17.25–20.01) ASD cases per 1000 births, whereas fathers aged 55–59 (&geq;99.7th percentile) had 16.35 (95% CI: 15.11–17.58) ASD cases per 1000 births. In analyses stratified by co-parental age, increased risk due to advancing paternal age was evident only with mothers &leq;35 years. In contrast, advancing maternal age increased risk regardless of paternal age. Advancing parental age was more strongly associated with ASD with ID, compared with ASD without ID.Conclusions: We confirm prior findings that advancing parental age increases risk of ASD, particularly for ASD with ID, in a manner dependent on co-parental age. Although recent attention has emphasized the effects of older fathers on ASD risk, an increase of n years in maternal age has greater implications for ASD risk than a similar increase in paternal age. [ABSTRACT FROM PUBLISHER]

Objective: Original case descriptions of autism noted that parents of the affected children tended to be highly educated and intelligent, a characterization that has endured publicly. Recent genetic studies indicate that risk for autism spectrum disorders (ASD) is associated with high intelligence. We examined the association between paternal intelligence and ASD, considering co-occurring intellectual disability (ID) and attention-deficit/hyperactivity disorder (ADHD).Method: We used a register-based cohort study design including 360,151 individuals with fathers conscripted to the Swedish military, resident in Stockholm, Sweden, born from 1984 to 2008, and followed until December 31, 2011, for diagnosis of ASD, ADHD, and/or ID. Risk of neurodevelopmental disorders relative to paternal IQ (rated on a 9-point scale) was assessed using a score of 5 (average intelligence) as the referent in models accounting for potentially nonlinear relationships and clustering of siblings.Results: We observed an association between high paternal IQ and offspring risk of ASD without ID/ADHD in models adjusted for individual and family characteristics (ORIQ=9 1.32, 95% CI 1.15-1.52), an association that appeared to be driven largely by the fathers' score on the technical comprehension portion of the test (ORTechnical IQ = 9 1.53, 95% CI 1.31-1.78). Conversely, low paternal IQ was associated with ASD+ID (ORIQ = 11.78, 95% CI 1.27-2.49) and ASD+ADHD (ORIQ = 11.40, 95% CI 1.16-1.70); low paternal IQ was strongly associated with ID (ORIQ = 1 4.46, 95% CI 3.62-5.49) and present also for ADHD (ORIQ = 11.56, 95% CI 1.42-1.72)] without co-occurring ASD or ID.Conclusion: The relationship between paternal IQ and offspring risk of ASD was nonmonotonic and varied by the presence of co-occurring disorders, probably reflecting phenotypic diversity among affected individuals. [ABSTRACT FROM AUTHOR]