Hot flashes are more dangerous than previously thought - so prepare now, experts warn

By Sandee LaMotte of CNN

The rush of heat comes out of nowhere, so fierce for some that their faces burn and sweat streams from every pore of their bodies. Welcome to the hot flashes and other symptoms of approaching menopause - an experience experts say about 75 percent of women will share if they live long enough.

Even if menopause is years or decades away, it's time to pay attention - because according to emerging science, the menopause experience may be damaging to future health.

Unpublished studies presented Wednesday at The Menopause Society's annual meeting in Philadelphia found intense hot flashes are associated with an increase in C-reactive protein, which is a marker of future heart disease, and to a blood biomarker that might predict a later diagnosis of Alzheimer's disease

"This is the first time science has shown hot flashes are linked to blood biomarkers of Alzheimer's disease," said Dr Stephanie Faubion, director of the Mayo Clinic's Women's Health Specialty Clinic in Jacksonville, Florida, and medical director for The Menopause Society.

"This is another piece of evidence telling us that hot flashes and night sweats may not be as benign as we have thought them to be in the past," said Faubion, who was not involved in the studies.

Alzheimer's risk

Nearly 250 women between the ages of 45 and 67 experiencing menopausal symptoms wore a device to objectively measure the quality of their sleep for three nights. The women were also fitted with sweat monitors to record their hot flashes on one of those nights. Researchers then drew blood samples from the study participants and examined them for a specific protein biomarker of Alzheimer's disease called beta-amyloid 42/40. 

"Beta-amyloid 42/40 is considered a marker of amyloid plaques in the brain, which is one of the components of the pathophysiology of Alzheimer's disease dementia," said lead study author Dr Rebecca Thurston.

"We found night sweats were associated with adverse beta-amyloid 42/40 profiles, indicating that hot flashes experienced during sleep may be a marker of women at risk of Alzheimer's dementia," said Thurston, a professor of psychiatry, epidemiology and psychology who directs the Women's Biobehavioral Health Laboratory at the University of Pittsburgh's Pitt Public Health.

The biomarker does not identify whether a person has clinical Alzheimer's disease, Thurston said, only the possibility of developing the disease in the future.

"In other words, hot flashes at night aren't causing this risk. They're just a marker of people who are at increased risk," Faubion said. "Similarly, we don't know if treating night sweats would diminish the risk. We don't know that." 

The study also looked at two biomarkers for tau protein, the other hallmark sign of Alzheimer's disease, but did not find any association, Thurston said. "These biomarkers are still undergoing rapid development, and while they've been validated at this point there's still more we need to learn."

Due to the objective sleep measurements, researchers were able to rule out the role of poor sleep, a well-known risk factor for dementia, in the findings. Prior research that also controlled for sleep found hot flashes and night sweats were linked to poor memory performance and alterations in brain structure, function and connectivity.

"All of the findings are converging to underscore there's something about these nocturnal vasomotor symptoms, aside from sleep itself, that is affecting the brain," she said.

Woman having night sweats
Intense hot flashes could indicate an increased risk of Alzheimer's and heart disease in the future, new research found. Photo credit: Getty Images

Heart disease 

Another study presented at the conference by Thurston's team looked at inflammatory markers for heart disease. Prior research by Thurston found women who said they had frequent or persistent hot flashes during early menopause had a 50 percent to 80 percent increased risk of cardiovascular events such as heart attacks, stroke and heart failure.

Frequent moderate to severe hot flashes can often last seven to 10 years, on average, and less frequent or severe hot flashes can last even longer, according to experts.

In this new research, scientists used sweat monitors on 276 women who were part of the MSHeart study to measure the frequency and intensity of hot flashes more objectively during day and night.

"A lot of people actually underreport their hot flashes, saying they're not having many when they really are," Faubion said. "Using this monitor is an objective way to quantify them." 

Researchers compared the frequency and intensity of hot flashes with blood measurements of C-reactive protein, a protein that indicates inflammation levels in the body that is used to determine the risk for heart disease and stroke in people who don't already have heart disease.

Results showed hot flashes during the day were associated with higher levels of C-reactive protein, even after adjusting for other potential causes such as age, body mass index (BMI), education, ethnicity, the hormone oestradiol and race.

"This is the first study to examine physiologically measured hot flashes in relation to inflammation and adds evidence to a growing body of literature suggesting that hot flashes may signify underlying vascular risk," said lead author Mary Carson, a clinical and bio-health doctoral student in the department of psychology at the University of Pittsburgh, in a statement.

What you can do 

Since heart disease is the leading cause of death for women in the world, doctors should begin asking patients about their experiences with hot flashes as a risk factor for future disease, Faubion said.

"Women who may be having night sweats in particular may need to assess their cardiovascular risk in general," she said.

"As for what to do, the recommendations are going to be the same as for heart and brain health: better sleep, proper diet, regular exercise program, reducing stress, staying socially connected and doing something that stimulates your brain."