The hot flashes that bedevil so many women as they enter menopause don't appear to be linked to poorer heart health, new research suggests. The exception to that finding may be if hot flashes persist for many years after the onset of menopause, or if the hot flashes start many years after menopause begins. "It's very reassuring for the women who have the most common pattern of hot flashes. There is no signal of an increased cardiovascular risk for women who have hot flashes around the time of menopause," said study author Dr. Emily Szmuilowicz, assistant professor of medicine at Northwestern University Feinberg School of Medicine in Chicago. "But there may be a suggestion of increased cardiovascular risk among the smaller group of women who experience these symptoms for the first time many years after menopause or who have them for many years." The study was presented this week at the Endocrine Society annual meeting in Houston.
A woman is considered to be in menopause one year after her last menstrual cycle. As much as 85 percent of women, by some estimates, will experience hot flashes during that time -- and possibly in the years leading up to it, said Dr. Cynthia Stuenkel, a menopause expert and clinical professor of medicine at the University of California-San Diego. "We know that hot flashes are a very normal experience for women going through menopause," Stuenkel said. Much of the underlying physiology of hot flashes remains a mystery, experts say. But in the past few years, some research suggests hot flashes may be associated with higher risks of cardiovascular disease.
A study published last year based on data from the Women's Health Initiative study -- a large, long-term look at postmenopausal women -- found that those who had late-onset hot flashes were at a higher risk of heart attacks and death during the study period. (Women who had hot flashes around the time of menopause faced no added risk, and perhaps even a lower risk of heart attack than women with no hot flashes.) The current study was a follow-up to the prior study, measuring biological markers to try to determine what the underlying mechanism might be. Szmuilowicz and her colleagues examined data on nearly 60,000 postmenopausal woman with an average age of 64 who were asked about hot flashes, including when they started getting them and how many years they persisted. Compared to women who didn't have hot flashes, women who got hot flashes around the time of menopause onset were no more likely to have certain markers associated with a heightened risk of heart disease. Those markers include blood-pressure levels and white-blood-cell counts, which can be a sign of inflammation, Szmuilowicz said.
But women whose hot flashes emerged an average of 14 years after menopause and those who had persistent hot flashes (those who had them both around menopause and many years later) had higher blood-pressure readings and higher white-blood-cell counts. Women who had only early hot flashes also had better readings on a marker for blood vessel function than women who didn't have hot flashes or night sweats, although there was no difference in women with late or persistent hot flashes. In women with persistent hot flashes, blood glucose and insulin levels also were higher, which may indicate diabetes risk. There was no association between diabetes risk factors and women in any of the other hot-flash groups.
Although the science on hot flashes remains murky, experts said women experiencing persistent or late-onset hot flashes may be wise to try to lower their risk for heart disease and stroke, including keeping blood pressure and weight in check, exercising and eating a healthy diet. "Menopause is a good time for women to step back and take stock of their health," Stuenkel said. "There are a whole lot of things women can due to decrease their risk." Because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal. SOURCES: Emily Szmuilowicz, M.D., assistant professor, medicine, Northwestern University Feinberg School of Medicine, Chicago; Cynthia Stuenkel, M.D., clinical professor, medicine, division of endocrinology and metabolism, University of California-San Diego; June 25, 2012, presentation, Endocrine Society annual meeting, Houston