Does hormone therapy for menopause increase the risk of dementia?

big new study Danish researchers have suggested that hormone therapy, which women use to manage menopausal symptoms, is associated with an increased risk of developing Alzheimer’s disease and other types of dementia. The study also found that women who started treatment before age 55 and short-term users were also at increased risk.

The study’s authors cautioned that they could not distinguish between hormonal effects and the symptoms of menopause that drove women to treatment, and that menopause itself is associated with an increased risk of dementia. And in the same journal in which the Danish study was published, researchers from the Mayo Clinic and Harvard Medical School said: editorialtitled “Causality unlikely,” noted that the study showed no evidence that hormone therapy causes Alzheimer’s disease or other dementias.

Utilizing the Danish National Register, the study examined the medical records of more than 5,500 women diagnosed with dementia and Alzheimer’s disease between 2000 and 2018, and their diagnoses of those diseases. Not compared with more than 55,800 women. The study found that women who used hormones were 24 percent more likely to develop dementia (including Alzheimer’s disease) than women who didn’t use hormones.

Survey results reverberate previous research identified some Association Some had similar limitations to the current study between hormone intakes for menopause and dementia.of 2003The Women’s Health Initiative in the United States has found that women over the age of 65 taking hormone therapy have a higher risk of developing dementia than women taking a placebo.

“Like any drug treatment, hormone therapy also has side effects,” said Dr. Nelsang Purhadi, a researcher at the Danish Dementia Research Center at Copenhagen University Hospital Rigshospitalet and lead author of the recent study. Stated. “These should be weighed against the advantages.”

Dr. Purhadi noted that women in this and similar studies should not be so alarmed as to abandon hormone therapy treatment. Last week, the North American Society of Menopausal Medicine issued a notice to its membership of board-certified physicians that the study “does not change practice,” said Stephanie Stefanie, medical director of NAMS and a board member of the association. Dr. Fabion said. Mayo Clinic Women’s Health Center.

He added that while the study is a source of uncertainty and fear, it doesn’t provide much useful information.

confounder

Dr. Fabion said the biggest limitation of the study was that it was observational and could not establish causality.

Some experts suggest that the true connection may be between menopausal symptoms and dementia. “If you have symptoms of menopause, such as hot flashes, insomnia, depression, or foggy head, you’re more likely to seek hormones,” says Lisa, director of Alzheimer’s disease prevention programs at Weill Cornell Medicine. Dr Moscone said. Studies have linked these symptoms to the development of Alzheimer’s disease and other dementias.

For example, hot flashes are associated with high-intensity amounts in white matter, small lesions in parts of the brain that contain fibers that connect neuronal cells, Dr. Moscone said. research published A study last year showed that more frequent hot flashes were associated with increased white matter signal intensity. The lesion “is considered a risk factor for dementia,” said Dr. Moscone. (It’s unclear whether hot flashes damage the brain or whether hot flashes and white matter damage share an underlying cause.)

Middle-aged insomnia is believed to be caused by night sweats Risk factor They may develop neurodegenerative diseases later in life. “Certain proteins that are precursors to Alzheimer’s disease accumulate in the brain throughout the day. Push them out of the brain,” said Dr. Pauline Maki, director of the Women’s Mental Health Research Program at the University of Illinois at the University of Chicago. “We know many women go through years of untreated hot flashes that interfere with sleep each night. So that’s an important consideration as well.” Studies have yet to show that is a risk factor for dementia, but this is an ongoing area of ​​research, Dr. Maki said.

Midlife depression (another common symptom of menopause) is also being considered Risk factor to develop dementia later in life.

The Danish study did not reveal whether these underlying problems motivated women to seek hormone therapy in the first place, nor did it consider a genetic predisposition to developing Alzheimer’s disease, although neither study did. Dr. Poorhadi conceded that this could be a viable explanation for the results.

contradictory evidence

Just as there have been previous studies showing a link between hormone therapy and neurodegenerative disease, there are also numerous studies showing the opposite: hormone therapy is linked to neurodegenerative disease. reduce risk Dr. Moscone said it influences the development of dementia and Alzheimer’s disease. In one observational study, Published in 2021examined the medical records of about 380,000 women and found that long-term use of hormone therapy had a seeming “protective effect” on neurodegenerative diseases overall.

And Dr. Moscone added: three another the study A study in which women were randomly given hormone therapy or a placebo (considered the gold standard for determining drug efficacy) found that hormone use did not adversely affect cognitive function. These studies include, published in 2013, Data from the Women’s Health Initiative Researchers in the United States concluded that starting hormone therapy before age 55 was the main factor in reducing adverse cognitive effects.

The experts also noted that the Danish study only looked at the effects of specific hormone preparations, estrogen and synthetic progestins, whereas bioidentical progesterone and hysterectomy-treated women noted that other formulations, such as estrogen alone, could have a significant impact. Dr. Fabion said the results were different. “We lump hormone therapy into one group, and we shouldn’t,” she says. “They are all very different compounds and do not affect the body in the same way, so we should stop referring to them as a single entity.”