ADHD Linked to Alzheimer Disease Across Generations
Risk for AD increased for parents of individuals with ADHD; associations attenuated with decreasing genetic relatedness
MONDAY, Sept. 13, 2021 (HealthDay News) -- There is an association for attention-deficit/hyperactivity disorder (ADHD) with Alzheimer disease (AD) and any dementia across generations, according to a study published online Sept. 9 in Alzheimer's & Dementia.
Le Zhang, from the Karolinska Institutet in Stockholm, and colleagues examined the extent to which ADHD is linked with AD and any dementia across generations. Swedish national registers were used to link a nationwide cohort born between 1980 and 2001 to their biological relatives (parents, grandparents, uncles/aunts). Cross-generational associations were examined using Cox models.
The researchers found that 3,042 parents, 171,732 grandparents, and 1,369 uncles/aunts of 2,132,929 index persons had a diagnosis of AD. The risk for AD was increased among parents of individuals with ADHD (hazard ratio, 1.55; 95 percent confidence interval, 1.26 to 1.89). The associations were attenuated with decreasing genetic relatedness but remained elevated in grandparents (hazard ratio, 1.11; 95 percent confidence interval, 1.08 to 1.13). A stronger association was seen for early- versus late-onset AD. The results were similar for any dementia.
"The findings suggest that there are common genetic and/or environmental contributions to the association between ADHD and dementia. Now we need further studies to understand the underlying mechanisms," Zhang said in a statement.
Two authors disclosed financial ties to the biopharmaceutical industry.