Estrogen Use Before 65 Linked To Reduced Risk Of Alzheimer's Disease

The study was part of the Women's Health Initiative Memory Study, which is a sub-study of the Women's Health Initiative (WHI), one of the largest U.S. prevention studies of postmenopausal women. The study looked at prior hormone use in 7,153 healthy women ages 65-79 before they enrolled in the WHI Memory Study. Researchers followed the women's cognitive health over an average of five years.

In that time, 106 of the women developed Alzheimer's disease or dementia. Dementia is a general term referring to the progressive decline in a person's cognitive function. Dementia can affect memory, attention, language and problem solving abilities. Alzheimer's is the most common type of dementia.

Prior studies have shown that hormone therapy started during the WHI Memory Study increased a woman's chance of dementia. The reduced risk of dementia was seen only with prior hormone therapy, used before study enrollment. Reduced risk was not affected by other examined factors. "We found that it didn't matter how old the woman was when she started hormone therapy, how long or recently she took it or what kind of prior therapy she used," said study author Victor W. Henderson, MD, of Stanford University in Palo Alto, CA, and Fellow of the American Academy of Neurology.

Women who began estrogen-only therapy after the age of 65 had roughly a 50-percent increased risk of developing dementia. The risk jumped to nearly double for women using estrogen-plus-progestin hormone therapy.

"Further studies are needed to support these findings and learn more about how hormone therapy affects the long-term cognitive health of women who begin use before age 65," said Henderson.

This research was presented at the American Academy of Neurology's 59th Annual Meeting in Boston, April 28 -- May 5, 2007.

The National Institutes of Health and Wyeth funded the Women's Health Initiative Memory Study.