Does HRT Increase Dementia Risk? What the Data Really Says

Recently a widely-reported study from Denmark suggested that women who took estrogen and progestin hormone replacement therapy (HRT) for menopausal symptoms had an increased risk of developing Alzheimer’s disease and other types of dementia within 20 years. The increased risk was seen in both short-term users who started the therapy at 55 or younger, as well as in long-term users. 

However, medical experts say the study is unable to draw a direct connection to dementia, and the overall benefits of HRT far outweigh the risks for many patients. In fact, in the same journal where the study was published, researchers from the Mayo Clinic and Harvard Medical School published an editorial, “A Causal Link Remains Unlikely,” emphasizing that the study didn’t provide evidence that HRT causes Alzheimer’s or other dementias. They noted that Alzheimer’s disease is twice as common in women than in men, making midlife exposures that might influence its risk in women considerable interest.

Erkan Buyuk, board-certified reproductive endocrinologist, infertility specialist and OB-GYN at RMA of New York who was not part of the study says HRT is the most effective therapy for hot flashes associated with menopause, which is why it is most commonly prescribed to menopausal women. 

“However, HRT has a wide range of additional benefits,” said Dr. Buyuk. “It has also been shown to reduce cases of coronary heart disease, colorectal cancer, genitourinary infections and death from all-cause mortality.” He adds that HRT can also decrease the risk of osteoporosis, weak bones, improve sleep, skin health, eye health and improve overall quality of life. 

How the study on HRT and dementia risk was conducted

Using Denmark’s national registry, the study assessed medical records of roughly 56,000 Danish women between 2000 and 2018. Of those women, 5,500 were later diagnosed with dementia or Alzheimer’s disease. 

Dr. Buyuk said that there are many types of medications used for menopausal symptoms and they each have different mechanisms of action with short and long-term side effects. However, the HRT that is used in this study is the standard regimen that is most commonly used.  

After controlling for a number of factors that could affect the development of dementia, such as age, sex, hypertension, thyroid disease and diabetes, the study found that women who used hormone therapy, even briefly, had a 24 percent higher rate of dementia and Alzheimer’s than the women who did not use hormones. 

The study also found that when women used 12 or more years of hormone therapy, diagnosis of dementia rose to 74 percent.

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