Heart Health After Hot Flashes a 'Wake-up Call'

Tara Haelle

September 27, 2019

CHICAGO — Hot flashes and night sweats are generally considered benign symptoms that women need to get through during changes in reproductive hormones related to the menopause transition, said Rebecca Thurston, PhD, director of the women's biobehavioral health laboratory at the University of Pittsburgh.

But symptoms might actually flag underlying health problems, she warned.

"What we're learning is that vasomotor symptoms actually may mean something for women's health," said Thurston, who is incoming president of the North American Menopause Society (NAMS).

She presented study findings that indicate that women who experience these symptoms are potentially at higher risk for a cardiovascular event here at the NAMS 2019 Annual Meeting. Cardiovascular risk factors need to be monitored closely in those affected, she said.

"We do not know that this association is causal; therefore, we do not know whether treating the vasomotor symptoms will impact women's cardiovascular health," Thurston explained.

More than 70% of women experience hot flashes and night sweats during menopause, and about 30% experience severe vasomotor symptoms, she reported. Symptoms can last up to 7 to 10 years and have a negative impact on women's quality of life.

Until recently, it was not clear whether these symptoms had any association with other health concerns. But new research, including Thurston's own work, has linked vasomotor symptoms to poor cardiovascular risk profiles and subclinical cardiovascular disease indicators.

What we're learning is that vasomotor symptoms actually may mean something for women's health.

It has been difficult to "rigorously examine the association between vasomotor symptoms and actual hard clinical outcomes — like heart attack, stroke, heart failure, and cardiovascular mortality" — because of the time between exposure and outcomes, she explained. Women typically experience vasomotor symptoms in their 40s and 50s, but don't suffer cardiovascular events until they are 65 years or older.

The prospective Study of Women's Health Across the Nation (SWAN) trial, which has been collecting data for more than 2 decades, provided an opportunity for Thurston and her colleagues to examine the association.

The study participants were 42 to 52 years at study enrolment, were pre- or early perimenopausal, had a uterus and at least one ovary, and were not taking hormone therapy. In the study cohort, 47% of the women were white, 28% were black, 9% were Latina, 9% were Japanese, and 7% were Chinese.

During annual clinic visits, women self-reported myocardial infarction, stroke, heart failure, percutaneous coronary intervention, and bypass surgery. SWAN researchers verified these reports in a subset of participants by checking medical records.

Women also completed questionnaires on the frequency of hot flashes and night sweats experienced in the previous 2 weeks. Investigators used cause of death listed on death certificates to determine whether deaths in the study population were related to a cardiovascular event.

Of the 3272 women included in the final analysis, 231 (7.1%) experienced a cardiovascular event during 22 years of follow-up.

Cardiovascular Risk

The 365 women who reported frequent vasomotor symptoms — at least six episodes of hot flashes or night sweats in the previous 2-week period — at baseline had more than twice the risk for a cardiovascular event than the 1986 women who reported no vasomotor symptoms at baseline, after the researchers controlled for study site, baseline age, and race or ethnicity (hazard ratio [HR], 2.16; < .001).

That risk was 51% greater in the frequent group than in the asymptomatic group when researchers controlled for cardiovascular risk factors and demographic characteristics (HR, 1.51; < .05), such as number of visits attended, education, financial strain, menopause status, smoking status, physical activity, blood pressure, body mass index, lipid level, insulin resistance, and hormone therapy started after study enrolment.

For women who reported one to five episodes of hot flashes or night sweats during a 2-week period at baseline, there was no significant increase in risk for cardiovascular events.

However, cardiovascular risk was 80% higher in women who reported frequent vasomotor symptoms in at least one-quarter of their clinic visits than in asymptomatic women (HR, 1.8; < .0001).

Some women began hormone therapy during the trial, but when researchers controlled for hormone therapy or excluded these women from the analysis, the findings did not change. They also did not change when researchers limited the analysis to cardiovascular events confirmed in medical records, took into account when vasomotor symptoms occurred, or excluded women who had undergone bilateral oophorectomy.

"We've done a lot of different probes of the 'why' question, and we have not yet been able to explain the association. We need to do more work to understand what is linking these," Thurston told Medscape Medical News.

She and other researchers have explored links between vasomotor symptoms and cardiovascular risk factors or demographic characteristics, and have even taken a "deep dive into different biological processes, such as autonomic nervous system inflammation," but it is still not clear whether the symptoms are just a signal or something more.

"At a minimum, I think these vasomotor symptoms are a marker telling us something about these women that we really need to pay attention to — possibly adverse changes in their cardiovascular health that are going on during the menopause transition," she said.

Women often experience degradation of cardiovascular health more rapidly during menopause than during other times in their lives. Midlife is also a time when women can be "stretched in a lot of different directions," often putting the health of others above their own, she pointed out.

This study emphasizes how important it is that women prioritize their own health, especially quitting smoking, maintaining a healthy weight, participating in regular physical activity, and taking medications to manage any cardiovascular-related conditions, she added.

This study could be a "wake-up call" for women and their healthcare providers to take hot flashes seriously and not dismiss them as unimportant, said Stephanie Faubion, MD, director of the Mayo Clinic Center for Women's Health in Rochester, Minnesota, and medical director for NAMS.

"I think it's a lot harder to blow off a woman with hot flashes if it's associated with a heart disease risk," she told Medscape Medical News. "We still don't know if treating with hormone therapy, for example, is going to reduce that risk, but we do know there's an association, so we need to be paying attention to other risk factors for these women."

These results are a surprise because most previous studies have attempted to link hormonal vasomotor symptom treatments to an increased risk for cardiovascular symptoms, said Ian Taras, MD, an obstetrician–gynecologist in private practice in Woodland Hills, California.

"Unfortunately, our scientific world places much more emphasis on quantity of life than on quality of life," he told Medscape Medical News. "Accordingly, healthcare providers and the public do not take vasomotor symptoms as seriously as they should," aside from those who experience the decreased quality of life they cause and the practitioners who see the effects of the symptoms.

"This study will metaphorically grab healthcare providers by the collar and shake them into realizing that vasomotor symptoms also affect quantity of life," Taras said. That might lead providers to be more accepting of treatment for hot flashes, he added, although he acknowledged it is not yet clear whether treatment reduces later cardiovascular risk.

But it is important for providers to know about the menopausal symptoms their patients experience. "The first thing providers can do is just ask," Thurston said. "Let's get these menopausal experiences on the radar."

This research was funded by the National Institutes of Health. Thurston reports consulting for Astellas, Pfizer, and Proctor & Gamble. Faubion reports consulting for Mithra. Taras reports being a speaker for Duchesnay, AbbVie, and Lupin.

North American Menopause Society (NAMS) 2019 Annual Meeting: Abtract S-1. Presented September 26, 2019.

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