Long-Term Hormone Therapy Treatments May Increase Alzheimer’s Disease Risk In Women: Study

Side effects of hormone therapy taken during menopause, especially in combination therapy that involves estrogen and progesterone, may increase the risk of developing Alzheimer’s disease later in life, according to the findings of a new study.

In a report published last week in the medical journal The BMJ, researchers from the U.K. say they found signals that indicate an increased risk of Alzheimer’s disease with long-term hormone therapy treatments, but the risk was very low for women who used estrogen only hormone therapy.

The study involved a review of data on 118,000 women ages 55 and older, with a diagnosis of dementia between 1998 and 2020. The researchers compared that data to a control group of nearly 500,000 women.

Roughly 14% of women who had dementia, and 14% of women in the control group had used menopausal hormonal therapy.

Overall, there was no increased risk of developing dementia linked to using hormone therapy. In fact, the risk of dementia decreased among women younger than 80 years who had been taking estrogen-only therapy for 10 years or more. However, researchers noted a slightly increased risk of developing Alzheimer’s disease among women who had used estrogen plus progestogen therapy for between five and nine years. This was the equivalent to roughly five to seven extra cases of dementia per 10,000 women years.

Roughly 80% of all menopausal women experience symptoms such as hot flashes, sleep disturbance, depression or cognitive dysfunction. About 70% of menopausal women may also have symptoms associated with warnings of future neurological decline. However, in some cases, sex hormones, especially estrogen, have been shown to have a neuroprotective effect.

The findings of this study indicate using only estrogen may have this neuroprotective effect. However, using estrogen plus progesterone appears to increase the risk of decline in neurological function, especially Alzheimer’s disease, the researchers concluded.

A study from Finland published in 2019 had similar findings, indicating women taking combination therapy, estrogen plus progesterone, had an increased risk of developing Alzheimer’s disease. The overall risk was low, but when started by women younger than 60 the risk increased 17%.

“This study gives estimates for risks of developing dementia and Alzheimer’s disease in women exposed to different types of menopausal hormone therapy for different durations and has shown no increased risks of developing dementia overall,” the researchers wrote. “It has shown a slightly increased risk of developing Alzheimer’s disease among long term users of oestrogen-progestogen therapies.”