Parental age and attention-deficit/hyperactivity disorder (ADHD)

Area of Science:

• Pediatrics
• Genetics
• Public Health

Background:

• Previous research suggests a link between young maternal age and Attention Deficit Hyperactivity Disorder (ADHD) in offspring.
• The role of genetic, socioeconomic, and environmental factors in this association requires further investigation.

Purpose of the Study:

• To examine the association between parental age and ADHD risk using sibling comparisons.
• To determine the extent to which genetic, socioeconomic, and early environmental factors explain this association.

Main Methods:

• A large Danish population-based cohort study (N=943,985) from 1991-2011.
• Sibling-matched Cox regression analysis to control for shared familial factors.
• ADHD diagnosis based on ICD-10 criteria for Hyperkinetic Disorder (HKD).

Main Results:

• Children of parents aged 20 or younger had over double the risk of ADHD compared to those with parents aged 26-30.
• Sibling comparisons attenuated the association, but a trend of increased ADHD risk with decreasing maternal age persisted.
• No significant association was observed between paternal age and ADHD risk in sibling comparisons.

Conclusions:

• Genetic and socioeconomic factors partially explain the association between parental age and ADHD.
• The persistent trend with maternal age suggests potential contributions from pregnancy or early-life environmental factors.
• Supporting young parents is a public health priority, even if environmental factors account for a smaller portion of the risk.