P&S Journal: Winter 1997, Vol.17, No.1
Estrogen and Alzheimer's
Postmenopausal women who used estrogen for a year or more significantly delayed or decreased their risk of developing Alzheimer's disease in a study reported in Lancet. Taking estrogen postmenopausally lowered a woman's risk of developing the disease by as much as 5 percent a year. Women who used estrogen for 10 years, for example, would reduce their risk by 50 percent.
"This is the most definitive study to date indicating that estrogen use during the menopausal period reduces the risk of Alzheimer's disease," says Dr. Richard Mayeux, the Gertrude H. Sergievsky professor of neurology, psychiatry, and public health (epidemiology) and senior author of the study.
The study correlated history of estrogen use, medical history, APOE genotype (the major risk factor for Alzheimer's), ethnic group, age, and education for 1,124 postmenopausal women. The researchers interviewed and examined the women at the start of the study and again one to five years later. Of the 968 women who never used estrogen, 158--or 16 percent--developed Alzheimer's. Only nine women--5.8 percent--of the 156 who used estrogen for more than a year developed the disease. Women who used estrogen for less than one year were protected, but to a lesser extent. Furthermore, estrogen users who did develop Alzheimer's did so significantly later in life than non-users. These protective effects of estrogen held true even in the face of other risk factors, such as APOE genotype, education and socioeconomic levels, and family history.
"This study shows that estrogen can significantly delay the onset of Alzheimer's disease," Dr. Mayeux says. "If you're destined to get Alzheimer's, you're going to get it. But if you delay the onset by four to five years in a 70- or 80-year-old individual, you're significantly improving the quality of that individual's remaining years."
Estimates in 1991 put the total cost of Alzheimer's disease in the United States at $67.3 billion.
The study's co-authors were Drs. Ming-Xin Tang, Diane Jacobs, Yaakov Stern, Karen Marder, Peter Schofield, Barry Gurland, and Howard Andrews. The research was funded by the National Institute on Aging and the Alzheimer's Association.