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Timing of hormone therapy may be critical in reducing Alzheimer’s disease risk

New research indicates that women who used hormone therapy within 5 years of menopause had a reduced risk for developing Alzheimer’s disease. However, the risk was not reduced for women who had initiated hormone therapy 5 or more years after menopause.

“This has been an area of debate because observational studies have shown a reduced risk of Alzheimer’s disease with hormone therapy use, while a randomized controlled trial showed an increased risk,” study researcher Peter P. Zandi, PhD, of Johns Hopkins University, said in a press release. “Our results suggest that there may be a critical window near menopause where hormone therapy may possibly be beneficial. On the other hand, if started later in life, hormone therapy could be associated with an increased risk of developing Alzheimer’s disease.”

Zandi and colleagues followed 1,768 women aged 65 years and older for 11 years. The women provided a detailed history of when menopause and the use of hormone therapy began. During the study period, 176 women developed Alzheimer’s disease.

Results showed that women who used any type of hormone therapy within 5 years of menopause had a 30% less risk for developing Alzheimer’s disease (95% CI, 0.49-0.99), particularly if women used hormone therapy for 10 years or more. The risk was not reduced for women who initiated the therapy 5 years or more after menopause, and rates were increased among women who initiated “opposed” estrogen-progestin compounds within the 3 years before the study commenced (adjusted HR=1.93; 95% CI, 0.94-3.96), according to the researchers.

“While this well-designed study supports the possibility that short-term hormone use may reduce the risk of Alzheimer’s disease, more research is needed before we can make new clinical recommendations for women and their use of hormone therapy,” Victor Henderson, MD, of Stanford University and a fellow of the American Academy of Neurology, said in the press release. Henderson wrote an accompanying editorial in Neurology.

Disclosure: See the study for a full list of financial disclosures.