Frequent menopausal vasomotor symptoms (VMS), including hot flashes and night sweats, lasted for more than seven years during the transition to menopause for more than half of the women in a large study and African American women reported the longest total VMS duration, according to a new study.

VMS are the hallmark of the menopausal transition and they can affect the quality of women's lives. Up to 80 percent of women experience VMS during the transition to menopause and, despite the pervasiveness of these symptoms, robust estimates about how long VMS last are lacking.

Nancy E. Avis, Ph.D., of Wake Forest School of Medicine, Winston-Salem, N.C., and coauthors analyzed data from the Study of Women's Health Across the Nation (SWAN), a multiracial/multiethnic study of women transitioning to menopause that was conducted from February 1996 through April 2013. The analyses included 1,449 women with frequent VMS, which was defined as occurring at least six days in the previous two weeks.

Study results indicate that the median (midpoint) total VMS duration was 7.4 years. Women who were premenopausal or early perimenopausal when they first reported frequent VMS had the longest total VMS duration (median greater than 11.8 years) and persistence of frequent VMS after a final menstrual period (median of 9.4 years). Women who were postmenopausal at the onset of VMS had the shortest total VMS duration after a final menstrual period (median of 3.4 years).

Compared with women of other racial/ethnic groups, African American women reported the longest total VMS duration (median of 10.1 years) and Japanese and Chinese women had the shortest VMS duration (median of 4.8 years and 5.4 years, respectively). The median total VMS durations were 6.5 years for non-Hispanic white women and 8.9 years for Hispanic women, according to the results.

Additional factors related to longer duration of VMS were younger age, lower educational attainment, greater perceived stress, greater sensitivity to symptoms, and higher depressive symptoms and anxiety at first report of VMS.

"These findings can help health care professionals counsel patients about expectations regarding VMS and assist women in making treatment decisions based on the probability of their VMS persisting. In addition, the median total VMS duration of 7.4 years highlights the limitations of guidance recommending short-term HT [hormone therapy] use and emphasizes the need to identify safe long-term therapies for the treatment of VMS," the study concludes.

Citation: JAMA Intern Med February 16, 2015 doi:10.1001/jamainternmed.2014.8063