Men’s brains age faster, but women still face higher Alzheimer’s risk
A new analysis published in PNAS challenges long-held assumptions about why women are more likely to develop Alzheimer’s disease. While men’s brains were found to shrink faster than women’s with age, the study concludes that this difference does not account for women’s higher rates of Alzheimer’s diagnosis, pointing instead to more complex biological and social explanations, Kazinform News Agency correspondent reports.
The research, led by Anne Ravndal and colleagues at the University of Oslo, analyzed more than 12,600 MRI scans from 4,700 cognitively healthy people aged 17 to 95. Drawing data from 14 cohorts, including the Alzheimer’s Disease Neuroimaging Initiative and the Australian Imaging Biomarkers and Lifestyle study, the team tracked how brain structures changed over time in men and women.
After controlling for differences in head size and lifespan, the researchers found that men experienced steeper losses in cortical thickness and subcortical volume, particularly in regions such as the parahippocampal cortex, putamen, and caudate nucleus, all of which are involved in memory and movement. Women, in contrast, showed more limited cortical changes but greater ventricular expansion, a marker of overall brain shrinkage that typically accompanies aging.
Aging patterns don’t explain Alzheimer’s risk
Despite these findings, the study found no sex difference in hippocampal decline, the brain region most affected in Alzheimer’s disease. Even after adjusting for education and life expectancy, men still showed broader patterns of age-related atrophy, suggesting that women’s higher Alzheimer’s prevalence cannot be explained by faster brain aging.
The team notes that men’s faster brain aging aligns with broader biological patterns, such as more rapid epigenetic aging and metabolic decline observed in men across multiple studies. Yet women tend to live longer, and this longevity might expose them to Alzheimer’s risk for a greater portion of life. Moreover, diagnostic and survival biases could also play a role - women’s symptoms may be recognized earlier, or they may survive longer after onset.
The study also highlights possible differences in how the APOE ε4 gene, a major genetic risk factor for Alzheimer’s, interacts with sex. Prior work suggests that the variant may increase tau protein accumulation - a key feature of Alzheimer’s pathology - more strongly in women than in men.
The authors stress that future research must look beyond structural brain changes to understand the gender gap in dementia. They call for deeper investigation into sex-specific biological mechanisms, social and behavioral factors, and differences in diagnosis and care.
Earlier, Kazinform News Agency reported that women carry a higher genetic risk of depression.