Study is first to look at device-validated hot flashes in relation to endothelial function
Women who experience hot flashes earlier in life appear to have poorer endothelial function–the earliest sign of cardiovascular disease–than women who have hot flashes later in life or not at all, according to two new studies scheduled for presentation at the American College of Cardiology’s 64th Annual Scientific Session in San Diego.
“We tend to think of hot flashes as solely a quality of life issue, but these studies–based on data from two very different samples–call that into question,” said Rebecca C. Thurston, Ph.D., associate professor of psychiatry, psychology and epidemiology, University of Pittsburgh, and lead author of both studies. “Hot flashes appear to be more toxic in younger than older women.”
The research suggests early onset hot flashes may serve as a red flag to help identify women at greater cardiovascular risk who could benefit from more aggressive risk reduction early in midlife, Thurston said. The studies, funded by the National Heart, Lung, and Blood Institute, add to emerging research linking hot flashes with cardiovascular risk, and endothelial dysfunction in particular.
In the first of the two studies, researchers enrolled 189 healthy peri- or post-menopausal women and examined the relationship between hot flashes and flow-mediated dilation, a marker of endothelial function that tests how well the vessels dilate in response to sheer stress on the vessel wall. Unlike similar studies that have relied solely on women self-reporting hot flashes, women in this study wore a monitor for 24 hours to confirm and quantify hot flashes. Flow-mediated dilation was assessed through a noninvasive ultrasound of the brachial artery in the forearm, which Thurston said correlates well with responses in the coronary artery.
More hot flashes over a 24-hour period were associated with significantly lower flow-mediated dilation and, therefore, poorer endothelial function in younger women, defined in this study as age 52 and younger. Hot flashes were not related to the early indicator of heart disease in the older women. The findings remained significant even after controlling for age, race, previous hormone use, menopausal stage and body mass index.
It seems the number of hot flashes matters too. On average, women in the study had nine hot flashes in the 24-hour period in which they were monitored. Having any number of hot flashes at a younger age was related to a three percent reduction in flow-mediated dilation compared to the younger women with no symptoms, which Thurston said is clinically significant. In particular, flow-mediated dilation in younger women who had 10 or more hot flashes a day was reduced by almost half compared to younger women without hot flashes, indicating the more hot flashes these women had, the more evidence of endothelial dysfunction.
Thurston will present the studies, “Physiologically-Assessed Hot Flashes are Associated with Poorer Endothelial Function Among Early Midlife Women” and “Early-Onset Menopausal Vasomotor Symptoms are Associated with Endothelial Dysfunction: The National Health Lung and Blood Institute-Sponsored Women’s Ischemia Syndrome Evaluation (WISE)” on Monday, March 16 at 9:30 a.m. PT/12:30 p.m. ET/4:30 p.m. UTC in Poster Hall B1.