A comprehensive Danish study published in The BMJ has found a potential link between menopausal hormone therapy (HRT) and an increased risk of dementia and Alzheimer’s disease. The results of the study suggest that not only those who take the drug long-term, but also those who take it during the menopause may be at risk.
Menopausal hormone therapy, known as HRT, is often used to relieve menopausal symptoms such as hot flashes and night sweats. This therapy may include pills containing estrogen alone or a combination of estrogen and progestogen, as well as patches, gels, and creams.
Previous large observational studies have already shown that long-term use of menopausal hormone therapy is associated with the development of dementia. These findings were also confirmed in the largest clinical trial on this topic, the Women’s Health Initiative Memory Study.
However, the impact of short-term use of menopausal hormone therapy around the age of menopause, which is currently recommended, still needs to be studied. In addition, the effect of different treatment regimens on the risk of dementia remains unclear.
Researchers from Denmark conducted a study to examine the association between the use of estrogen and progestin combination therapy and the development of dementia. They analyzed data from a national registry of 5,589 dementia cases and 55,890 age-matched controls without dementia from 2000 to 2018. Study participants were all Danish women aged 50-60 years in 2000 who were dementia-free and had no medical conditions that prevented the use of menopausal hormone therapy.
The researchers took into account various factors such as education, income, hypertension, diabetes and thyroid disease.
The study found that those who received estrogen-progestin therapy had a 24% higher risk of developing all-cause dementia and Alzheimer’s disease compared to those who did not use the therapy. This increased risk was seen even in women who received the therapy at age 55 or younger.
The risk was also found to be affected by the length of time the drug was taken. The incidence of dementia was higher with longer use of the drug, ranging from 21% for one year or less to 74% for more than 12 years.
The study also found that the increase in the incidence of dementia was similar with continuous (daily estrogen and progestins) and cyclic (daily estrogen and progestins 10-14 days per month) treatment regimens.
In the editorial, the researchers emphasized the need for further studies to investigate the potential causal relationship between menopausal hormone therapy and the risk of dementia. They recognized the strengths of the Danish study, but cautioned against concluding direct causality based on observed associations alone.
Dr. JoAnn Pinkerton, executive director of the North American Menopause Society, said: “This study adds to the body of evidence suggesting a potential association between menopausal hormone therapy and dementia risk. It is critical to further explore these findings and determine the underlying mechanisms.”
Dr. Pauline Maki, professor of psychiatry and psychology at the University of Illinois at Chicago, said, “While this study does not establish causality, it raises concerns about the long-term effects of menopausal hormone therapy on brain health.”