ROCHESTER, Minn., July 12 (UPI) -- Although scientists are unsure of the effects of starting estrogen therapy in menopausal women before age 65, a recent study suggests it can reduce the risk for Alzheimer's disease.
Women who were less then three years past menopause showed lower levels of amyloid deposits in their brains, a hallmark of Alzheimer's disease, after being treated with an estrogen patch, which researchers at the Mayo Clinic say shows earlier hormone therapy could be a beneficial method of preventing the degenerative cognitive disease.
The average age of women at menopause is 51 in the United States, though women typically are not treated with estrogen replacement therapy until around age 65.
Researchers say a rapid decline in estrogen after menopause -- defined as occurring 12 months after a woman's last menstrual period -- may increase the risk of late-onset Alzheimer's disease. Among women with the gene APOE e4, a gene commonly linked to the disease, this dip in hormones increases the risk for developing Alzheimer's.
"If our results are confirmed in the larger group of women, this finding has the potential to change the concepts for preventive interventions that drive the Alzheimer's disease field today," Dr. Kejal Kantarci, a radiologist at the Mayo Clinic, said in a press release. "It also may have a significant impact on women making the decision to use hormone therapy in the early postmenopausal years."
For the study, published in the Journal of Alzheimer's Disease, researchers in the Kronos Early Estrogen Prevention Study treated 118 postmenopausal women between the ages of 52 and 65 with either a transdermal patch containing 17β-estradiol, oral estrogen or a placebo for four years. Among women without the APOE e4 gene, estrogen treatment was not seen to affect Alzheimer's disease likelihood.
Among the 68 women with the gene, however, researchers performed positron emission tomography scans to measure amyloid deposit development in their brains three years after treatment had stopped, seven years after the start of the trial. Of the 68 women, 21 were treated with the patch, 17 received oral estrogen and 30 were given a placebo.
Overall, earlier treatment with the estrogen patch was seen to reduce incidence of Alzheimer's disease when compared to placebo, and the oral treatment was not linked to lower amyloid deposits at all. The most significant effect of estrogen was seen among participants with the APOE e4 gene, researchers report.
"The association of transdermal 17β-estradiol therapy in recently menopausal women with lower amyloid deposition has the potential to change the concepts for preventive interventions that drive the field, and may have a significant impact on women making the decision to use hormone therapy in the early postmenopausal years," researchers wrote in the study.