Research studies are continuously trying to explain why more women are affected by Alzheimer's disease than men. There are various biological and genetic factors that cause this discrepancy. The average life expectancy for women is 81 years, for instance, compared to 76 years for men which makes woman more susceptible to dementia, including Alzheimer’s.
However, researchers are attempting to understand the underlying reasons as to why women are more affected by the disease. Researchers are also working on the development of gender-specific treatments.
According to the 2015 Alzheimer's Disease Facts and Figures from the Alzheimer’s Association, out of the 5.1 million people age 65 and older with AD living in the United States, 3.2 million are women and 1.9 million are men.
A large part of the research done on this topic points to two factors: genetics and hormones. A gene known as APOe4 is found in 20 percent of the population. Men and women have about the same chances of carrying the APOe4 gene, which produces a protein in the liver that transports cholesterol and fatty acids in the body. The risk is 10 times higher for someone who has two copies of the gene.
According to an article in the Washington Post, research suggests that the APOe4 gene confers its Alzheimer’s risk unevenly in women. A study led by Michael Greicius, medical director of Stanford Center for Memory Disorders, found that women with the APOe4 gene were twice as likely to get Alzheimer’s as women who did not carry the gene.
The risk factor appeared to be slightly different between men who had the gene and those who did not.
According to Walter A. Rocca, professor of neurology and epidemiology at the Mayo Clinic in Rochester, Minnesota, women who carry the APOe4 gene have a much higher risk of getting Alzheimer’s than men of the same age who do not have the gene.
While this phenomenon is not fully understood, scientists think that the APOe4 gene appears to interact with estrogen to create certain conditions that can lead to Alzheimer’s.
The role of estrogen in relation to Alzheimer’s is a topic that is continuously researched.