Attention-deficit/hyperactivity disorder and Alzheimer's disease and any dementia: A multi-generation cohort study in Sweden

Introduction We examined the extent to which attention-deficit/hyperactivity disorder (ADHD), a neurodevelopmental disorder, is linked with Alzheimer's disease (AD) and any dementia, neurodegenerative diseases, across generations. Methods A nationwide cohort born between 1980 and 2001 (index persons) were linked to their biological relatives (parents, grandparents, uncles/aunts) using Swedish national registers. We used Cox models to examine the cross-generation associations. Results Among relatives of 2,132,929 index persons, 3042 parents, 171,732 grandparents, and 1369 uncles/aunts had a diagnosis of AD. Parents of individuals with ADHD had an increased risk of AD (hazard ratio 1.55, 95% confidence interval 1.26-1.89). The associations attenuated but remained elevated in grandparents and uncles/aunts. The association for early-onset AD was stronger than late-onset AD. Similar results were observed for any dementia. Discussion ADHD is associated with AD and any dementia across generations. The associations attenuated with decreasing genetic relatedness, suggesting shared familial risk between ADHD and AD.

Automated summary

The study found an intergenerational association between attention-deficit/hyperactivity disorder (ADHD) and Alzheimer's disease (AD) and other forms of dementia and neurodegenerative diseases, with the association weakening with decreasing genetic relatedness.