Hormone Replacement Therapy May Reduce Alzheimer's Risk

A new study indicates that starting HRT within 5 years of the onset of menopause is key to producing a neuroprotective effect.

Women who use hormone replacement therapy (HRT) within 5 years after the onset of menopause may significantly decrease their risk of developing Alzheimer’s disease (AD), according to the results of a study published online on October 24, 2012, in Neurology.

The study adds to a longstanding debate among researchers over the role of HRT in neuroprotection. Some studies have indicated that HRT is helpful in preventing dementia, while others have indicated the opposite. In general, observational studies have tended to show protective qualities, but the Women’s Health Initiatives Memory Study (WHIMS), which was stopped early in 2002 due to concerns about cardiac and cancer risks, actually found that HRT increased the risk of dementia.

The researchers in the current study base their findings on the population-based Cache County Study, which followed 1768 women from Cache County, Utah, all aged 65 years or older at baseline, from 1995 through 2006. Drawing on data from the same cohort, the researchers had associated HRT with neuroprotection in a 2002 study published in the Journal of the American Medical Association. For the current study, they used an additional 7 years of data—providing more detail and specificity—to reexamine the association between HRT and risk of developing AD.

Of the study participants, 1105 (62.5%) reported using HRT—some with only estrogen, others with estrogen and progestin. Over the course of the study, women who used HRT had a 20% reduced risk of developing AD compared with nonusers, although this reduction was not statistically significant. However, when the researchers looked at the timing of HRT initiation, they found that those who initiated HRT within 5 years of menopause had a statistically significant 30% reduction in AD risk and that those who initiated HRT later had no difference in AD risk compared with nonusers of HRT.

These findings appear to have reopened the discussion on HRT’s role in neuroprotection, a discussion that the WHIMS study seemed to have closed. Nonetheless, on October 23, 2012, the U.S. Preventive Services Task Force published a recommendation statement in the Annals of Internal Medicine cautioning postmenopausal women against using HRT to prevent chronic conditions such as dementia.

Ms. Wick is a visiting professor at the University of Connecticut School of Pharmacy and a freelance writer from Virginia.