Parental Age and Autism Spectrum Disorders Among New York City Children 0-36 Months of Age.

We examined trends in autism spectrum disorders (ASD) and the association of ASD with parental age among young New York City (NYC) children. Children born in NYC to resident mothers from 1994-2001 were identified through vital statistics records (N = 927,003). Records were linked to data from NYC Early Intervention (EI) Program through 2004. The independent parental age-specific odds of having an ASD before 36 months of age were estimated using multiple logistic regression controlling for risk factors. The increase in ASD attributable to changes in parental age at birth was examined. Births to mothers and fathers 35 years or older increased 14.9 and 11.5 %, respectively, between 1994 and 2001. ASD prevalence in EI increased significantly from 1 in 3,300 children born in 1994 to 1 in 233 children born in 2001. Children born to mothers ages 25-29, 30-34 and 35 or older had significantly greater odds of being diagnosed with ASD than children of mothers younger than 25 years (OR 1.5, 1.6, and 1.9, respectively). Children born to fathers ages 35 or older (OR 1.4) had greater odds of ASD than children of fathers younger than 25. The change in parental age accounted for only 2.7 % of the increase in ASD prevalence. Older paternal age and maternal age were independently associated with increased risk of ASD. However, while parental age at birth increased between the 1994 and 2001 birth cohorts in NYC, it did not explain the increase in number of ASD cases.