Understanding Why Women Are Twice as Likely to Develop Alzheimer’s

In a growing body of research, experts are investigating the reasons why women are disproportionately affected by Alzheimer’s disease, with findings suggesting biological differences related to chromosomes and hormonal changes during menopause. Published on July 7, 2025, in the Harvard Gazette by staff writer Alvin Powell, the article outlines significant insights from recent studies conducted by leading researchers in the field.

Alzheimer’s disease, characterized by memory loss and cognitive decline, presents a stark gender disparity. While it is commonly understood that women generally live longer than men, researchers assert that this alone cannot explain the alarming statistic that women are twice as likely to develop Alzheimer’s disease. According to Dr. Anna Bonkhoff, a resident and research fellow in neurology at Harvard Medical School and Mass General Brigham, the biological differences associated with sex chromosomes and hormonal levels are critical to understanding this phenomenon.

Women have two X chromosomes, while men possess one X and one Y chromosome. This chromosomal difference could contribute to variations in genetic expression related to Alzheimer's risk. Dr. Bonkhoff noted, "The X chromosome is rich in genes that regulate brain function and the immune system, which may leave women more susceptible to neurodegenerative diseases like Alzheimer’s."

Menopause, typically occurring between the ages of 45 and 55, marks a significant hormonal transition for women, characterized by a decline in estrogen and progesterone levels. Research led by Dr. Rachel Buckley, an associate professor of neurology at Harvard Medical School, indicates that this hormonal change may play a critical role in increasing the risk of cognitive decline. In a 2023 study published in the journal Science Advances, Dr. Buckley and her colleagues found that women undergoing hormone replacement therapy (HRT) after age 70 displayed significant tau protein accumulation in the brain, a hallmark of Alzheimer’s disease that correlates with cognitive decline.

Dr. Buckley explained, "Our findings suggest that while hormone replacement therapy may be beneficial for alleviating menopausal symptoms, its use in older women should be approached with caution given the potential risks associated with cognitive health."

The implications of this research extend beyond the individual, highlighting the need for gender-specific approaches to Alzheimer’s treatment and prevention. Dr. Bonkhoff emphasized that understanding sex differences in Alzheimer's can pave the way for new therapeutic strategies. "If we can find ways to incorporate sex differences into treatment protocols, we can optimize care for both men and women, which is crucial for effective Alzheimer’s management," she stated.

The epidemiological trends in neurological diseases reveal that conditions such as multiple sclerosis and migraines are more prevalent among women, while men are more commonly affected by Parkinson’s disease and brain tumors. This suggests that biological and environmental factors contribute significantly to gender disparities in neurological health.

As research continues, experts are calling for more comprehensive studies that investigate the interplay between sex hormones, genetic factors, and environmental influences on Alzheimer’s disease risk. Dr. Buckley plans to conduct further studies that will encompass a broader range of variables, including a woman's reproductive history and timing of hormone therapy, to better understand their relationships with cognitive health.

In conclusion, while the complexities of Alzheimer’s disease are still being unraveled, the increasing focus on how biological sex influences disease risk is imperative. The hope is that this research will not only enhance our understanding of Alzheimer’s but also lead to improved prevention and treatment strategies tailored to the unique needs of women and men.

The ongoing dialogue among researchers and medical professionals signifies a crucial step toward addressing the gender disparities in Alzheimer's disease and enhancing the overall approach to neurological health.

### References 1. Bonkhoff, A., et al., "Sex Differences in Alzheimer’s Disease and Stroke: A Review," Science Advances, 2023. 2. Buckley, R., et al., "Hormone Replacement Therapy and Tau Accumulation in Older Women," Science Advances, 2023. 3. National Institute on Aging. (2023). 4. Harvard Medical School. (2025). 5. Alzheimer’s Association. (2023). 6. World Health Organization. (2023). 7. U.S. National Library of Medicine. (2023).