Scientists at the University of California San Diego School of Medicine analyzed data from more than 17,000 middle aged and older adults and found that certain modifiable dementia risk factors appear to have a greater impact on women's cognitive function than men's. The findings were published May 19, 2026, in Biology of Sex Differences.

"Looking beyond which risk factors are most common, we found that some have a disproportionately larger impact on women's cognition," said Megan Fitzhugh, PhD, assistant professor of neurosciences at UC San Diego School of Medicine and first author of the study. "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."

Researchers say the findings could help explain why women account for nearly two thirds of Alzheimer's cases in the United States.

Women Bear a Larger Alzheimer's Burden

Nearly seven million Americans are currently living with Alzheimer's disease, and women make up the majority of those cases. Although women generally live longer than men, scientists say longer lifespan alone does not fully explain the gap.

Researchers are increasingly studying how biological, social, and lifestyle related factors combine to shape dementia risk differently in women and men. Many of these factors can potentially be changed through medical care or lifestyle adjustments.

For the new study, Fitzhugh and senior author Judy Pa, PhD, professor of neurosciences at UC San Diego School of Medicine, examined 13 established dementia risk factors using information from the Health and Retirement Study, a nationally representative group of U.S. adults in mid to late life.

The factors included education level, hearing loss, smoking, alcohol consumption, obesity, depression, physical inactivity, hypertension, diabetes, and other cardiometabolic conditions.

Key Dementia Risks Affect Women and Men Differently

The analysis uncovered several notable differences between women and men.

Women were more likely to report:

• Depression (17% compared with 9% in men)
• Physical inactivity (48% compared with 42%)
• Sleep problems (45% compared with 40%)

Women in the study also had slightly lower average educational attainment, which is considered a risk factor for later cognitive decline.

Men showed higher rates of:

• Hearing loss (64% compared with 50% in women)
• Diabetes (24% compared with 21%)
• Heavy alcohol use (22% compared with 12%)

High blood pressure was widespread in both groups, affecting roughly six out of 10 participants. Average body mass index for both sexes also fell within the overweight to obese range.

Some Risk Factors Had a Stronger Cognitive Impact in Women

The researchers found that several risk factors were linked to poorer cognitive performance more strongly in women than in men.

Conditions related to heart and metabolic health, including hypertension and elevated body mass index, showed steeper negative associations with cognition among women. Hearing loss and diabetes, despite being more common in men, were also tied to lower cognitive scores in women.

The findings suggest the same dementia risk factor may not affect everyone equally. A health issue that causes only moderate cognitive effects in men could potentially have a much stronger influence on women's brain health.

"These differences highlight the importance of considering sex as a key variable in dementia research," said Pa. "Sex differences are profoundly overlooked among many leading causes of death like Alzheimer's, heart disease and cancer."

Toward More Personalized Dementia Prevention

The results support growing interest in precision medicine, an approach that aims to tailor prevention and treatment strategies to individual characteristics, including sex.

Rather than focusing only on the most common dementia risk factors across the population, the researchers suggest it may be more effective to prioritize those that appear to have the greatest cognitive impact within specific groups.

The team emphasized that many of the risk factors identified in the study are modifiable, meaning there may be opportunities to reduce risk through targeted interventions.

For women, that could include greater attention to managing depression, increasing physical activity, and improving cardiovascular health, especially untreated hypertension.

Researchers Call for More Study

The researchers say more work is needed to understand why dementia risk factors may affect women differently. Possible explanations include hormonal influences, genetic differences, and unequal access to health care, though the exact interactions remain unclear.

"Ultimately, a more nuanced understanding of these differences could help us design smarter, more targeted interventions," Fitzhugh said. "That's an essential step toward reducing the burden of dementia for everyone, but especially for women, who are disproportionately affected."

The study, titled "Sex differences in modifiable risk factors of dementia and their associations with cognition," was funded by the National Institute on Aging (RF1AG088811, PI: Pa) and the Alzheimer's Association (SAGA23-1141238, PI: Pa).

The authors reported no conflicts of interest.