The protective association was not uniform across all groups. Women who initiated hormone therapy within ten years of menopause onset had an estimated 27 percent lower risk of cardiovascular disease events compared with women who did not initiate therapy. Among Black women, hormone therapy initiation during peri- and early postmenopause was associated with an estimated 49 percent lower risk of cardiovascular disease events compared with those who did not initiate therapy. By contrast, the analysis observed no clear risk reduction among women who initiated therapy more than ten years after menopause onset, nor among White women and other racial and ethnic groups. The researchers reported that the cardiovascular effect of hormone therapy initiation therefore varied by both timing and race and ethnicity, a pattern that the investigators described as notable given that Black women are more likely to experience severe vasomotor symptoms.

“The menopause transition represents a critical window for understanding how hormone therapy may relate to cardiovascular disease risk,” said Samar R. El Khoudary, Ph.D., M.P.H., professor and chair of the Department of Epidemiology at the VCU School of Public Health, a SWAN investigator and one of the senior researchers who led the study. “Our findings suggest that timing of initiation may influence cardiovascular outcomes.” El Khoudary also emphasized the analytical approach behind the result. “By using data from the SWAN study, we essentially were able to emulate a series of hypothetical clinical trials to gain a deeper understanding into how hormone therapy taken to mitigate vasomotor symptoms during peri- and early postmenopause influences cardiovascular risk over time,” she said. “It allowed us to examine clinically meaningful cardiovascular disease events over long-term follow-up in a population and treatment window that has been challenging to study prospectively.”

Despite the size of the observed associations, the researchers are explicit that the findings do not support using hormone therapy for cardiovascular disease prevention. This was not a randomized controlled trial, the gold standard method for testing biomedical treatments, and the observational design means that women who elect to use hormone therapy differ from women who do not on multiple characteristics that the analysis cannot fully address. “These findings point to women with vasomotor symptoms as those who may show cardiovascular benefit from hormone therapy initiated during the perimenopause and postmenopausal years,” said Rebecca C. Thurston, Ph.D., associate dean for Women’s Health Research at the University of Pittsburgh School of Medicine, a SWAN principal investigator and one of the senior researchers who led the study. “However, conclusions should be tempered by the observational nature of the study, and findings should not guide clinical practice.”

Thurston reinforced that caution in a separate statement, noting that women who choose hormone therapy differ from those who do not in ways including race, ethnicity, socioeconomic position and access to healthcare. “Our findings are thought provoking. However, caution should be exercised in their interpretation,” she said. “These data point to the need for a clinical trial specifically designed among midlife women with vasomotor symptoms.” El Khoudary echoed the same message for patients and clinicians. “We hope these findings help inform conversations between women and their healthcare providers about the potential benefits and risks of hormone therapy for vasomotor symptoms,” she said. “Studies like this can provide useful information, but the results should be interpreted carefully because other factors that were not measured may have influenced the findings. The findings also highlight the need for future clinical trials focused specifically on women during the menopause transition.”

Vasomotor symptoms, the clinical term for hot flashes and night sweats, affect up to 80 percent of women during their menopause transition. These symptoms last an average of seven to ten years, with their frequency and severity building up through perimenopause and typically peaking in early postmenopause. Hormone therapy, which replaces the estrogen and progesterone that women’s bodies stop producing after menopause, is currently the most effective treatment for mitigating these sensations of intense heat. “Hot flashes and night sweats have a significant impact on a woman’s quality of life and ability to work productively,” El Khoudary said. “While hormone therapy is an effective treatment for these symptoms, questions have remained about its cardiovascular effects, particularly the importance of when treatment is initiated during the menopause transition.” The new analysis addresses those questions specifically among women who sought treatment for symptoms rather than for other indications.

The long shadow of the Women’s Health Initiative helps explain why the question has remained contested. Clinical trials led by the Women’s Health Initiative in the early 2000s raised initial alarm over hormone therapy’s impact on heart disease, stroke, breast cancer and other risks, and this led to years of reluctance from both patients and providers in using the therapy. More recent research has suggested that the effect hormone therapy has on women’s hearts and vascular systems may vary depending on age and the timing of treatment, with women younger than 60 who begin treatment closer to menopause onset showing different levels of risk. Reflecting that evolving evidence on the benefits and risks of treatment, the U.S. Food and Drug Administration removed “black box” warnings from hormone therapy products in 2026. The new SWAN analysis adds population-specific, event-based evidence to this shifting landscape.

The knowledge gap the study targeted was substantial. Although a growing number of studies over the past twenty years have focused on hormone therapy and cardiovascular risk, no clinical trials have specifically evaluated the risk of cardiovascular events from taking hormone therapy for vasomotor symptoms during the menopause transition. To fill that gap, the researchers from VCU and the University of Pittsburgh turned to SWAN, which is the largest and longest observational study of its kind in the United States and was designed to better understand the health impacts of the menopause transition in women. Based on self-reported patient data, the team examined whether women who started hormone therapy for vasomotor symptoms were more or less likely to experience cardiovascular events over follow-up than women who did not begin treatment, using clinical data spanning two decades.

The mechanism behind the timing-dependent pattern remains unresolved. It is unclear why cardiovascular disease risk differs based on the timing of hormone therapy use, but the team believes it may be linked to differences in blood vessel health as women age, a hypothesis that future work will need to test directly. What the current analysis establishes is an association measured over long-term follow-up in a well-characterized cohort, with the strongest estimated benefits concentrated among women who started treatment within ten years of menopause onset and among Black women, and no clear reduction among women who started later or among White women and other racial and ethnic groups. The researchers also note that, as with any treatment, potential benefits must be weighed against risks, including the increased breast cancer risk observed with a longer duration of use.

The SWAN study is supported by grants from the Department of Health and Human Services and the National Institutes of Health, including the National Institute on Aging, the National Institute of Nursing Research, and the NIH Office of Research on Women’s Health. For the researchers, the immediate value of the work lies in sharpening the questions that a definitive trial must answer rather than in changing practice today. The analysis identifies a specific population, midlife women with vasomotor symptoms, and a specific treatment window, peri- and early postmenopause, in which the observed cardiovascular associations were most pronounced, while underscoring that unmeasured confounding and differences in healthcare access could have shaped the results. Until randomized evidence exists for this population and window, the authors position the findings as thought-provoking observational evidence that helps inform conversations between women and their healthcare providers about the potential benefits and risks of hormone therapy for hot flashes and night sweats.

Subject of Research: Observational study of menopausal hormone therapy timing and cardiovascular disease risk in midlife women with vasomotor symptoms

Article Title: Hormone therapy use for hot flashes and night sweats in peri- and early postmenopause linked to lower cardiovascular risk in women

Article References: Hormone therapy use for hot flashes and night sweats in peri- and early postmenopause linked to lower cardiovascular risk in women. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: hormone therapy, menopause, vasomotor symptoms, cardiovascular disease, SWAN study, perimenopause, postmenopause, hot flashes, JAMA Internal Medicine, observational study, women's health, estrogen