A recent paper published in the Journal Neurology, which analyzed over 900 people, suggests that almost half of all women in their nineties are suffering from dementia. The study carried out in California is one of a few looking specifically at the rates of dementia in the very old. However, given our increased life expectancies, the over ninety group is growing rapidly in many populations, including that of the United States. Importantly, there seems to be a sex difference in the risk for Alzheimer’s or dementia in general over the age of ninety.
In men, for instance, although there was an increase in the likelihood of having dementia over the age of ninety, it did not increase as much as it did in women. In women, the likelihood of having dementia doubled every five years after the age of ninety. Previous studies have suggested that the risk for dementia is higher in women than it is in men. But other studies have disputed this. This present study seems to confirm that the risk for women is greater than men, at least after the age of ninety years.
Therefore, if you divide dementia populations by sex over the age of ninety, about 45% of women will have dementia compared to 28% of men. Importantly the study also suggested that women who had used their brains (intellect) more throughout life and had achieved higher education, were much less likely to develop dementia than those who had not.
Understanding why women in this age group might be at higher risk will take additional studies. But it is known, for instance, that women are more likely than men to develop stroke and heart disease as they age. Both of these are independent risk factors for dementia and exacerbate Alzheimer’s symptoms.
Researchers at the Roskamp Institute are interested in finding new treatments for Alzheimer’s disease and clues from sex differences that confer different risks for Alzheimer’s are important because they may point to more treatment strategies.
Researchers have, for instance, speculated that estrogen is a protective factor for Alzheimer’s disease, but proactive treatment with estrogen has not been shown to be preventative in clinical trials. In the present study, the idea that vascular risk factors (which are more prevalent in women as they age) are contributory to Alzheimer’s is consistent with much of the work of Roskamp Institute scientists showing that in the presence of amyloid, damage to the vasculature is heightened and the consequences of vascular damage has greater impact on the brain in the presence of early Alzheimer’s disease than in normal individuals. These and other clues are leading Roskamp Institute scientists towards new treatments for the disease, some of which should be entering clinical trials in 2008.