Alzheimer's disease risks are gender specific

NEW YORK (Reuters Health) - The risks of developing Alzheimer's disease differ between the sexes, with stroke in men, and depression in women, critical factors, according to a French study.

Dr. Karen Ritchie at La Colombiere Hospital in Montpellier and colleagues studied 6892 adults age 65 and older. At the start of the study between 1999 and 2001, none had dementia, but 42 percent were deemed to have mild cognitive impairment.

In all, just over 6.5 percent of those deemed to be cognitively impaired developed dementia over the next four years, whereas 37 percent returned to normal levels of functioning. In just over half, no change was seen.

Progression from mild cognitive impairment to dementia was more likely among those who were depressed and who were taking so-called anticholinergic drugs, which influence chemical signaling in the brain.

A variation in the ApoE gene -- a known risk factor for dementia -- was also more common among those whose mild cognitive impairment progressed to dementia.

But risk factors also differed between the sexes, the results showed.

Men with mild cognitive impairment were more likely to be overweight, diabetic, and to have had a stroke. Men who had had a stroke were almost three times as likely to progress.

Women with mild cognitive impairment, on the other hand, were more likely to be in poorer general health, disabled, suffering from insomnia and to have a poor support network.

Women incapable of performing routine daily tasks, which would allow them to live without assistance, were 3.5 times as likely to progress. And those who were depressed were twice as likely to do so.

Stroke was not a risk factor for progression to dementia in women.

According to the investigators, novel risk factors for impaired cognition were recent anesthesia, less consumption of caffeine, tobacco and alcohol, appetite loss, and in women, less use of hormone replacement therapy.

SOURCE: Journal of Neurology, Neurosurgery and Psychiatry, online May 1, 2008.