Women Face a Hidden Alzheimer’s Risk Men Don’t, New Study Finds
Alzheimer’s disease disproportionately affects women. Of the roughly seven million Americans living with the condition, nearly two-thirds are women. Women also face about twice the lifetime risk of developing Alzheimer’s-related dementia as men. While women tend to live four to five years longer than men on average, researchers increasingly believe that longer lifespans tell only part of the story. Researchers from the University of California San Diego explored whether risk factors linked to Alzheimer’s disease differ between men and women — and whether those risk factors affect cognitive function differently by sex.
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The Risk Factors Aren’t the Same for Women and Men
The 2024 Lancet Commission on Dementia Prevention, Intervention, and Care identified 14 modifiable risk factors that, if addressed, could reduce an estimated 45% of dementia cases globally. These factors accumulate across the lifespan.
The new study builds directly on this framework, asking a crucial question: Do these risk factors operate the same way in women and men? The study, published in Biology of Sex Differences, analyzed data from more than 17,000 adults ages 40 and older participating in the Health and Retirement Study, a nationally representative U.S. cohort of older adults. Not all participants had data available for every risk factor, so sample sizes varied considerably. For example, BMI data were available for just over 6,000 participants, while diabetes data were available for nearly the entire cohort. The researchers assessed cognitive performance using the Telephone Interview for Cognitive Status, a widely used test that scores memory, attention, and other thinking skills on a scale of 0 to 27. The test measures cognitive function, not dementia itself.
The study found that women had a significantly higher prevalence of seven of the 13 risk factors examined, while men had a higher prevalence of only three. Hypertension, body mass index (BMI), and social isolation showed no clear overall sex difference. Men were more likely to have hearing loss, diabetes, and excessive alcohol use. Women, meanwhile, were more likely to have lower educational attainment, higher cholesterol, depression, physical inactivity, smoking, poor vision, and poor sleep.
Dr. Victor Henderson, a professor of epidemiology and population health and director of the NIH Stanford Alzheimer’s Disease Research Center, told Stanford Medicine News Center that men and women often experience dementia risk factors differently due to differences in biology and life experiences. He added that reducing modifiable dementia risk factors could help lessen the burden of Alzheimer’s disease. “If we can move the needle on those, we should be able to reduce the burden of Alzheimer’s,” he said. “And women stand to gain from that.”
Risk Factors Take a Bigger Toll on Women
Megan Fitzhugh, assistant professor of neurosciences at UC San Diego School of Medicine and first author of the study, said one of the most important findings was that some risk factors appeared to affect women’s cognition more strongly than men’s.
“This suggests that prevention efforts may be more effective if they are tailored not just to risk factor prevalence, but to how strongly each factor affects cognition in women versus men,” Fitzhugh said.
For example, although hearing loss and diabetes were more common among men, both were associated with greater declines in memory and thinking skills in women. Hypertension was also linked to poorer cognitive performance in both sexes, but the association was stronger in women. Women also appeared to gain more cognitive benefit from certain factors. More years of education were associated with better memory and thinking skills in both sexes, but the relationship was stronger in women.
Researchers also found a small positive association between higher total cholesterol levels and cognitive function in women, though not in men — a finding the authors said warrants further study. The difference became even more apparent when researchers looked at the overall number of risk factors a person had. Memory and thinking scores declined in both women and men as risk factors accumulated, but the decline was steeper in women.
In other words, women appeared to be more affected by both individual risk factors and the combined effect of multiple risks.
Rethinking Dementia Prevention
Because the study was observational, it cannot prove that these risk factors directly cause cognitive decline or dementia. Nor did it assess dementia diagnoses. Instead, it examined how risk factors were associated with cognitive performance at a single point in time. Taken together, the findings suggest that dementia prevention may need to be tailored by sex rather than assuming the same risk factors affect women and men equally. Fitzhugh said a more nuanced understanding of sex-based differences in Alzheimer’s risk factors could help researchers design smarter, more targeted interventions.
“That’s an essential step toward reducing the burden of dementia for everyone, but especially for women, who are disproportionately affected.”
