March 12, 2019
Hot flashes, mood swings, sleep problems. Many women trade these uncomfortable, annoying—even embarrassing—symptoms of menopause in for a prescription for oral hormone therapy, and never look back.
But now there’s a reason to reevaluate. Researchers reported on March 6 that long-term use of oral hormone therapy may be associated with a small increased risk of Alzheimer’s disease in postmenopausal women.
The study, conducted by researchers affiliated with six Finnish healthcare organizations, looked at nearly 85,000 postmenopausal women, between the ages of 70 and 80, diagnosed with Alzheimer’s disease between 1999 and 2013.
They found that use of oral hormone therapy for ten or more years in women who started the pills before age 60 had a 9% to 17% increased risk for Alzheimer’s disease. Women who used vaginal hormone therapy showed no increased risk.
Interestingly enough, prior research had indicated that hormone therapy reduces the risk of vascular dementia; but the new study found no such good news related to Alzheimer’s.
“It prompted us to do research on Alzheimer’s disease to see if the same results persisted, but it doesn’t look like hormonal therapy provided a protective effect on Alzheimer’s,” lead author Dr. Tomi Mikkola, supervisor for the obstetrics and gynecology doctoral program in clinical research at the University of Helsinki, told NBC News during a recent interview.
The specific reasons behind this increased risk are elusive, but biological differences between Alzheimer’s and vascular dementia may be one reason why, Mikkola said.
“Alzheimer’s is a completely different type of disease, we don’t know the mechanism behind the disease. What we know is that the disease has started decades before we see symptoms of memory loss,” said Mikkola.
Alzheimer’s disease is the sixth-leading cause of death in the United States. And of the nearly 6 million Americans who have been diagnosed with Alzheimer’s; fully two-thirds (66%) are women—including 200,000 under the age of 65. By 2050, experts predict that this number will rise to nearly 14 million, according to the Alzheimer’s Association.
“Given the lack of effective Alzheimer’s treatments and increased prevalence of the disease, medical and public health efforts have focused on primary prevention, including risk factors and preventive strategies, especially to women,” said Dr. JoAnn E. Manson, chief of the Division of Preventive Medicine at Brigham and Women’s Hospital in Boston, in an editorial written in response to the study.
“But the findings should not be a cause for alarm. For the short-term management of hot flashes, night sweats and disruptive sleep, the benefits of hormone therapy seem to outweigh the risk.”
In recent years, considerable attention has been given to the role of menopausal hormone therapy. Two 2017 studies found that the period when a woman starts to produce less estrogen, usually in her 40s, may be a critical point in whether she’ll go on to develop Alzheimer’s or not. Researchers concluded that the hormone estrogen is protective for a woman’s brain, stimulating growth and keeping it healthy. But the natural drop in estrogen during menopause means women lose that layer of protection, NBC News reported..
“Women should not use hormone therapy for the expressed purpose of trying to improve memory or reduce cognitive decline, but when used for early menopause the benefits are sure to outweigh the risk for short term treatment,” said Manson.
Because the study was observational, it isn’t definite that long-term hormone therapy causes Alzheimer’s disease. Other risk factors, including cardiovascular disease, diabetes, or having the APOE gene weren’t included in the study — these may have also contributed to many of the women’s increased dementia risk.
Research contact: @NBCNews