NEW YORK, Nov 19 (Reuters Health) -- Experts have long suspected that
estrogen therapy helps to prevent Alzheimer's disease in postmenopausal women.
Now, research in the Netherlands suggests that the hormone may protect younger
women from early onset of the illness, as well.
The study "provides further evidence that estrogen use has a protective
effect on Alzheimer's disease," write investigators led by Dr. Arjen Slooter of
the University Hospital Utrecht.
Alzheimer's disease is a degenerative brain disorder of unknown cause.
While most patients develop symptoms relatively late in life, in a minority of
cases the illness develops when patients are still in middle age.
The Dutch team questioned the families of 109 women affected by mild,
early-onset Alzheimer's, as well as the families of 119 healthy female
volunteers. The researchers focused on each woman's history of using birth
control pills that contained estrogen or using estrogen replacement therapy
after menopause.
The investigators found that the risk of early-onset Alzheimer's disease
declined as rates of estrogen use rose. Of the women with Alzheimer's disease,
10% had taken estrogen at some point in the past, compared with 20% of the
healthy volunteers.
Slooter and colleagues suggest that estrogen may affect the course of
Alzheimer's disease in several ways. First of all, they theorize that the
hormone may help prevent atherosclerosis ("hardening of the arteries"). In this
way, estrogen may increase blood flow to the brain, which has been linked in
previous studies with a reduced risk of Alzheimer's disease.
The Dutch experts also speculate that estrogen may help maintain complex
connections between brain cells, especially in those areas of the brain most
vulnerable to Alzheimer's.
In an interview with Reuters Health, Slooter pointed out that healthy
women enrolled in the study had achieved generally higher levels of education
compared with women with Alzheimer's disease. "Women who are more educated tend
to use estrogen more," Slooter noted, "and, as we have found, this group
develops Alzheimer's less often."
