Menopausal hormone therapy not linked to dementia risk

Reuters Health - 07/10/2021 - Women who take hormone therapy for menopause symptoms are no more likely to develop dementia than those who don't use the hormones, an observational study suggests.

Researchers examined data on 118,501 women aged 55 and older who received a dementia diagnosis between 1998 and 2020, as well as data on 497,419 female controls who were matched by index date, age, and general practice.

A total of 16,291 (14%) women who received a dementia diagnosis during the study period and 68,726 (14%) women without a dementia diagnosis had used menopausal hormone therapy more than three years prior to a dementia diagnosis or the index date, respectively.

Overall, menopausal hormone therapy use wasn't associated with an increased risk of developing dementia during follow-up, researchers report in The BMJ.

"Because of the efficiency of menopausal hormone therapy in easing memory and concentration loss symptoms associated with the menopause, we had in fact hypothesized a possible beneficial effect on the ageing brain," said lead study author Yana Vinogradova of the University of Nottingham in the UK.

However, the study didn't show any evidence of this, Vinogradova said by email. That suggests menopause hormone therapy should only be used to treat symptoms associated with menopause, and not as an intervention to help prevent or slow the development of dementia, Vinogradova said.

The study did identify some differences between estrogen-only therapy and combination therapy with both estrogen and progestogen, however.

Among women younger than 80 years old, taking estrogen-only menopausal hormone therapy for a decade or longer was associated with a small but significant reduction in the global risk of dementia (adjusted odds ratio 0.85).

However, women who took a combination of estrogen and progestogen therapy were significantly more likely to develop Alzheimer's disease, specifically, if they used the hormones between five and nine years (aOR 1.11) or for at least 10 years (aOR 1.19). This translated to an additional five cases per 10,000 person-years with five to nine years of treatment, and an additional seven cases per 10,000 person-years with 10 or more years of treatment.

One limitation of the study is that it's possible some women included in the analysis went through menopause prior to the start of the study and may have used hormone therapy during that period, researchers note. It's also possible that some women in the study who were classified as having a non-specific dementia diagnosis may have actually had Alzheimer's disease or mixed Alzheimer's-vascular dementia, researchers point out.

"I don't think clinical decision making around hormone replacement therapy should be based on concerns about effects on cognitive function because women in early menopause are taking hormones for management of menopausal symptoms and I don't think there's evidence of cognitive harm," said Dr. JoAnn Manson, professor of medicine at Harvard Medical School and chief of preventive medicine at Brigham and Women's Hospital in Boston, who coauthored a commentary accompanying the study.

There is some suggestion that estrogen alone should be more favorable, and that women who take estrogen plus progestogen may want to limit their exposure to five years or less, Dr. Manson said by email.

"That's consistent with findings for breast cancer to limit exposure to no more than five years," Dr. Manson said.

SOURCE: https://bit.ly/3DjsXOu and https://bit.ly/2Yv5xXq The BMJ, online September 29, 202

By Lisa Rapaport



Posted on 7 October 202114 October 2021