Risk factors for autism spectrum disorder in the Thai population.

Unlabelled: Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder commonly prevalent in children worldwide including Thailand. However, there are very few studies thus far addressing risk factors for ASD in Thai children. This case-control study aims to investigate whether various risk factors especially socioeconomic status, advanced parental age (age >35 years), perinatal factors, maternal autoimmune diseases, and family history of neuropsychiatric illnesses were associated with the risk of having an offspring with ASD. There were 235 children with ASD (age 8.44 ± 3.37 years) and 235 controls (age 8.39 ± 3.37 years) enrolled in this study. The risk of developing ASD in these children included advanced paternal age (adjusted odds ratio (AOR) = 3.49, 95 % confidence interval (CI) = 2.05-5.96), family history of neuropsychiatric illnesses particularly if such disorders came from the paternal side of the child's family (AOR = 2.87, 95 % CI = 1.29-6.39), and having unemployed mothers (AOR = 1.65, 95 % CI = 1.08-2.54).

Conclusion: This study supports previous findings of Western countries where risk factors for ASD tend to occur in children whose fathers were of advanced paternal age and in the families with neuropsychiatric illnesses particularly if such disorders came from the paternal side of the child's family.

What Is Known: • Family history of neuropsychiatric disorders and advanced paternal age are risk factors for ASD in the offspring previously identified in the studies in Europe and North America. What is New: • To our knowledge, this is the first study documenting risk factors for ASD in the Asian population. • Our study supports previous findings of Western countries where risk factors for ASD tend to occur in the families with neuropsychiatric illnesses particularly if such disorders came from the paternal side of the child's family.