Objectives: This study aimed at evaluating advanced parental age as a risk factor for autism spectrum disorder (ASD) in an Omani cohort. Methods: This case-control study compared 278 ASD cases with 722 gendermatched controls, retrieved from the electronic records of the Developmental Paediatric Clinic, Sultan Qaboos University Hospital, Muscat, Oman, between January 2015 and June 2016. Results: Most ASD cases were male (76.6%) and mostly diagnosed between 3–4 years of age, with more than 50% of the cases originating from Muscat and Batinah governorates. Compared to controls, mothers from the case group had significantly higher educational levels (post-secondary education versus high school/no formal education: odds ratio [OR] = 1.62, 95% confidence interval [CI]: 1.197–2.192). In a multivariate logistic regression, the OR of maternal age as a risk for ASD increased dramatically with advancing age category (using age <25 as reference, OR = 3.39, 6.12, 7.86 and 13.13 for age categories 25–29, 30–34, 35–39 and ≥40 years, respectively). The ORs of advancing paternal age as a risk for ASD were also statistically significant (using age <30 as reference, OR = 2.20, 2.36 and 3.12 for age categories 30–34, 35–39 and 40–44 years, respectively); however, there was a drop in the effect with paternal age ≥45 years (OR = 1.42; 95% CI: 0.64–3.15). Conclusion: Both maternal and paternal increased age were associated with a higher risk of ASD; however, the association was more pronounced and more consistent with advanced maternal age compared to paternal age.

Objectives: This study aimed at evaluating advanced parental age as a risk factor for autism spectrum disorder (ASD) in an Omani cohort. Methods: This case-control study compared 278 ASD cases with 722 gendermatched controls, retrieved from the electronic records of the Developmental Paediatric Cl...