Could Hormone Therapy Protect Against Alzheimer Disease?

Strong evidence does not exist for a protective association between postmenopausal hormone therapy (HT) use and Alzheimer disease (AD) or dementia, according to a new study. However, the researchers did observe a reduced AD risk among those with long-term self-reported HT use.

“Neuroprotective effects of estrogen have been observed in experimental animals, but clinical trials on postmenopausal HT use have not been successful, including the largest clinical trial to date, the Women’s Health Initiative Memory Study,” the investigators said. “Observational studies support use of HT against AD if initiated around menopause in some but not all studies. Similarly, register-based studies have yielded conflicting results.”
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They used 20-year follow-up data from the Kuopio Osteoporosis Risk Factor and Prevention study cohort and sent self-administered questionnaires to all women aged 47-56 years, residing in Kuopio Province, Eastern Finland, starting in 1989 until 2009, every 5th year. Register-based information on HT prescriptions was available since 1995. The researchers identified probable AD cases, based on DSM-IV and National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer’s Disease and Related Disorders Association criteria, from the special reimbursement register (1999-2009). The study population included 8195 women (227 cases of incident AD).

They found postmenopausal estrogen use to be not associated with AD risk in register-based or self-reported data. Long-term self-reported postmenopausal HT was associated with reduced AD risk. The researchers obtained similar results with any dementia diagnosis in the hospital discharge register as an outcome.

“The strengths of our study include its large sample size, long follow-up time, relatively homogenous population, clinically verified AD cases, prescription-based validation of HT use, and control for various important comorbidities,” the investigators said. “Confounders and exposures were measured with the same questions during the follow-up.”

The researchers are currently examining how common postmenopausal estrogen use is among older women.

—Mike Bederka

Reference:

Imtiaz B, Tuppurainen M, Rikkonen T, et al. Postmenopausal hormone therapy and Alzheimer disease: a prospective cohort study [published online February 15, 2017]. Neurology. doi: 10.1212/WNL.0000000000003696.