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Experts say menopause hot flashes have been linked to memory difficulties in some women. Grigorii Galasuk/Getty Images
  • Researchers report that “hot flashes” during sleep are associated with biomarkers for increased risk of Alzheimer’s disease.
  • In their study, researchers noted that sleep itself was not found to elevate risk.
  • They say the study is a caution to women who experience sleep hot flashes to reduce their controllable risk factors for developing Alzheimer’s.

Menopausal women who experience frequent hot flashes during sleep may be at elevated risk of developing Alzheimer’s disease.

In a new study, researchers from the University of Pittsburgh and the University of Illinois also report that the more hot flashes a woman has, the higher the risk of developing Alzheimer’s.

The research is being presented at the annual meeting of The North American Menopause Society in Philadelphia. It hasn’t been published yet in a peer-reviewed journal.

Women are at higher risk of Alzheimer’s than men. Two-thirds of people with the degenerative neurological disease are female.

Decreased estrogen levels after menopause is one suspected reason, although the cause of Alzheimer’s disease remains unknown.

Hot flashes have been associated with poor memory performance and alterations in brain structure, function, and connectivity.

“There has been a convergence of findings showing that hot flashes – particularly when objectively measured and occurring during sleep – are associated with poorer memory performance as well as greater markers of small vessel disease risk in the brain, which has been linked to future dementia,” Dr. Rebecca Thurston, a study author and director of women’s bio-behavioral health at the University of Pittsburgh Department of Psychiatry, told Medical News Today. “This study further adds to that literature linking hot flashes – and particularly sleep hot flashes — to markers of poorer brain health.”

The research is the first study to establish a link between hot flashes and recently identified biomarkers for Alzheimer’s disease.

Researchers tracked hot flashes using portable sensors to monitor skin temperature changes among 250 middle-aged women, then cross-referenced their data with the occurrence of biomarkers indicating elevated Alzheimer’s risk among the study population.

The researchers reported an association between hot flashes and night sweats and increased white matter hyperintensities, a biomarker for small vessel disease in the brain that can lead to diseases such as dementia.

“We do not yet know the underlying mechanisms, as some most intuitive potential mechanisms such as sleep and estradiol levels did not explain the associations seen here,” said Thurston. “Interestingly, these associations were not explained by sleep itself. There may be something particularly important about these nocturnal hot flashes that we have not appreciated up to this point.”

“Given the adverse effect on quality of life and financial burden of [Alzheimer’s disease], it’s important that we learn as much as possible about potential causes and warning signs so we can be proactive before the onset of [Alzheimer’s],” said Dr. Stephanie Faubion, medical director of The Menopause Society, in a press statement.

“Among other things, these findings indicate that women who experience frequent hot flashes, particularly during sleep, may warrant [Alzheimer’s] dementia risk reduction efforts,” said Thurston, who led the research team alongside Dr. Pauline Maki, a professor of psychiatry at the University of Illinois at Chicago.

Dr. Mindy Goldman, chief clinical officer for Midi Health, a virtual care clinic focused on helping women navigate midlife hormonal transition, told Medical News Today that hot flashes, night sweats, poor sleep, and brain fog are among the most common symptoms experienced by women during perimenopause and menopause.

“Many women will find poorer word recall and not feeling cognitively as sharp,” said Goldman. “Often we think that the cognitive complaints are a secondary result — that women who are having hot flashes and night sweats often have disrupted sleep and poor sleep can affect memory and recall. And previously it was thought that the hot flashes and night sweats are more of an annoyance and not anything that is a potential marker of health issues; that is changing.”

Goldman noted that the Study of Women’s Health Across the Nation (SWAN) has associated more hot flashes with negative effects on lipids, insulin resistance, and other markers for heart disease.

“This study adds to our knowledge that hot flashes aren’t just an annoyance and really could have impacts on health risks,” she said. “Although the brain fog that women often complain of is not the same as true cognitive loss, this is one of the first studies to actually suggest a mechanism by which hot flashes and night sweats could impact development of dementia and other neurologic diseases like stroke.”

“Although this is just an association and certainly this early study cannot imply that hot flashes and night sweats cause dementia, it continues to reinforce our knowledge that the menopausal transition has important effects on women’s overall health. And importantly, that symptoms of menopause should not just be ignored,” said Goldman.

Thurston said that the women with nighttime hot flashes should see the study findings as “a wake-up call to do what they can to take care of their health.”

“Right now, some of the best ways to preserve brain health are to engage in all of those healthy behaviors we know are important – such as engaging in regular exercise, eating a healthy diet, sleeping adequately, treating any mental health conditions, and treating any risk factors such as high blood pressure and diabetes,” she said. “There is some evidence that treating hot flashes with a non-hormonal intervention may help improve cognition, but much more [research] needs to be done in that space.”