There are many theories as to what may cause Alzheimer's disease but here’s one thing researchers know for sure: Women are diagnosed with various forms of dementia, including Alzheimer's, at greater rates than men. In fact, the Alzheimer’s Association’s 2011 Alzheimer’s Disease Facts and Figures report shows that 3.4 million of the 5.4 million Americans living with Alzheimer’s are female.
Why the Gender Discrepancy?

The current state of research seems to favor the simplest explanation for this phenomenon: Women just live longer. According to Malaz Boustani, MD, assistant professor of medicine at the Indiana University School of Medicine and a center scientist with the Indiana University Center for Aging Research, "Alzheimer's disease depends so much on time. Men tend to die earlier, and therefore they have less prevalence of Alzheimer's. There is a mortality difference."
On average, a girl born in 2005 is expected to live to age 80, according to the U.S. Centers for Disease Control and Prevention. A boy born that same year is expected to live to age 75. According to current consensus, that's why more women tend to develop Alzheimer's disease. They are simply more vulnerable to the greatest risk factor associated with Alzheimer's: advancing age.
Alzheimer's Symptoms in Men Vs. Women


Alzheimer's also appears to affect men and women differently. Here are some ways in which the condition can present itself in men versus women:
  • Men with Alzheimer's disease tend to develop more aggression — physical, verbal, and sexual — than women do as the disease progresses. They also tend to wander and perform socially inappropriate actions more frequently than women diagnosed with Alzheimer's.
  • Women with Alzheimer's disease tend to become more reclusive and emotionally unstable. They hoard items more often than men do, refuse help more often, and exhibit laughter or crying at inappropriate moments. They also seem more vulnerable to depression and to suffering from delusions.
Alzheimer's Risk: Other Roles Gender Might Play

New studies have found that hormonal differences might also play a role in increasing the risk of Alzheimer's in women. Beyond that, there appear to be gender differences in which risk factors for Alzheimer's affect men and women. Gender also appears to affect how Alzheimer's develops, since men and women exhibit different symptoms of dementia.
Gender is a factor in Alzheimer's disease for "a combination of reasons," says Allen Levey, MD, chair of neurology at Emory University School of Medicine and director of the Emory Center for Neurodegenerative Disease and Alzheimer’s Disease Center. "There are more women who are living longer. There may also be an increased risk for women beyond that. There has been a lot of research pointing toward the effects of female hormones, like estrogen, on dementia."
One study, for instance, has found that hormone replacement therapy can increase a person's risk of developing dementia. Another study found that high or low levels of a thyroid hormone called thyrotropin may be associated with an increased risk of Alzheimer's disease in women.
Gender also seems to play a role in which risk factors matter in the development of dementia. A French study found that men who had suffered a stroke were three times more likely to develop dementia, while stroke seemed to have no effect at all as a risk factor in women. But women with depression were twice as likely to suffer from dementia, and women unable to live without assistance due to an inability to perform routine tasks were 3.5 times more likely to develop dementia.
Researchers will continue to probe these gender differences in hopes of finding different ways to help men and women with Alzheimer's disease and, perhaps, find new treatments or, eventually, a cure.