Autism spectrum disorder and parents' age: a case-control study in Brazil

Autism spectrum disorder (ASD) has become a public health problem with major family, social, and economic impacts. This study aimed to estimate the association between ASD and parents' age at the time of their child's birth. A case-control study was performed, consisting of 243 individuals with ASD (cases) and 886 neurotypical controls. A semi-structured questionnaire was applied, following by multiple logistic regression. Associations between ASD and paternal age (in years) from 25 to 34 (OR = 1.65; 95%CI: 1.01-2.71), 35 to 44 (OR = 1.62; 95%CI: 0.96-2.73), and ≥ 45 (OR = 2.44; 95%CI: 1.14-5.00); and maternal age from 25 to 34 (OR = 2.38; 95%CI: 1.54-3.37) and ≥ 35 (OR = 2.09; 95%CI: 1.29-3.39) were significant when assessed in independent models. However, when included in a single model, only maternal age from 25 to 34 (OR = 2.27; 95%CI: 1.45-3.55) and ≥ 35 years (OR = 2.15; 95%CI: 1.21-3.83) remained associated with ASD. The association was stronger when both parents were older (OR = 4.87; 95%CI: 1.71-13.80). The results have important implications for clinical psychiatry and public health, since parents' age at childbirth has increased. Emphasis is needed on the prevention of late childbearing and screening and follow-up of children born to these couples.