A new study suggests that menopausal women who experience frequent hot flashes could be at increased risk for subclinical cardiovascular disease.
“Women with high levels of hot flashes had significantly higher intima-media thickness compared with women with low levels of hot flashes,” said lead investigator Rebecca Thurston, PhD, from the University of Pittsburgh. “Low-frequency hot flashes were not a problem from a cardiovascular standpoint. The women we need to pay close attention are the ‘super flashers’ — the women who report a lot,” she said.
The study is the first to compare the frequency of hot flashes with the thickness of the intima and media layers of the carotid artery, which is an indicator of subclinical atherosclerosis. Results were presented at the North American Menopause Society 2015 Annual Meeting.
All 304 women in the study cohort were nonsmokers, in their mid-50s, and free of clinical cardiovascular disease. In addition, most of the women were postmenopausal, overweight (body mass index, 29 kg/m²), and had normal blood pressure.
Hot flashes were assessed with physiologic monitoring and with electronic diaries. Intima-media thickness was assessed with carotid ultrasound.
Half the women reported no hot flashes. The other half reported an average of four per day, although ambulatory hot flash monitoring showed an average of 10 physiologic hot flashes per day in this group.
“Women often under-report their hot flashes. This is something to keep in mind,” said Dr Thurston.
Super Flashers and Cardiovascular Risk
Intima-media thickness was significantly higher in women with high levels of hot flashes, defined as up to 12 per day identified on physiologic monitoring, than in women with low levels of hot flashes, defined as four or less per day, after adjustment for age, site, race, education, weight, lipid levels, blood pressure, nightshift work, and medication for hypertension, diabetes, and cholesterol.
“Physiologic hot flashes explained more variance in intima-media thickness than any of the other risk factors,” including estradiol levels in the blood, Dr Thurston reported.
“Frequent hot flashes may be a marker of underlying risk, although it is not known whether treating the hot flashes will have any impact on underlying cardiovascular risk,” she added. “We cannot necessarily say there is a causal link from these data.”
She stressed that super flashers — women reporting five or six hot flashes a day, corresponding to at least 12 on physiologic monitoring — need to be kept up to date on cardiovascular risk factor screenings.
This is “in line with previous reports showing adverse cardiometabolic health in women experiencing vasomotor symptoms,” said Taulant Muka, MD, from Erasmus University Medical Center in Rotterdam, the Netherlands.
This study “extends previous findings by showing that the association between hot flushes and subclinical measures of atherosclerosis persists after correction for established CVD risk factors and endogenous sex hormones levels,” he said.
However, in a recent a systematic review and meta-analysis Dr Muka was involved in, vasomotor symptoms were associated with an unfavorable cardiovascular risk profile, but not with measures of subclinical atherosclerosis (Maturitas. 2015;81:353-361).
Cause or Consequence of Cardiometabolic Problem
Still, unlike in previous studies, Dr Thurston’s team “assessed physiological hot flushes, which is a more accurate measure,” Dr Muka explained. But the cross-sectional design “makes it difficult to define whether hot flushes are a cause or consequence of adverse cardiometabolic health.”
“Therefore,” he said, “it remains unclear whether vasomotor symptoms can be used as markers of CVD. We need larger studies with longitudinal design to establish this hypothesis.”
“Previous studies have tied hot flashes to other indices of subclinical cardiovascular disease, but this study is the first to suggest a link between intima-media thickness and hot flashes,” said Mary Norine Walsh, MD, medical director of the heart failure and cardiac transplantation programs at the St. Vincent Heart Center of Indiana in Indianapolis, who is vice president of the American College of Cardiology.
“The results of this very small study should be interpreted with caution,” she said. “Intima-media thickness itself as a risk discriminator remains controversial, and some of the women in this study may have had other significant CVD risk factors that weren’t adequately accounted for.”
“Most important,” she added, “hot flashes for peri- and postmenopausal women are exceedingly common. They are present in the vast majority of women and don’t yet indicate a need to change the current practice of CVD risk assessment.”
Source: North American Menopause Society (NAMS) 2015 Annual Meeting: Abstract S-12. Presented October 2, 2015.