Women who start symptoms such as hot flashes and sweats when they begin the menopause appear to be at lower risk of heart disease,
stroke, and death, according to a study led by researchers at Northwestern Memorial Hospital in Chicago, USA.
However, this was not the case for women who started symptoms later in the menopause: compared to women with no symptoms at all, they appeared to have a higher risk of cardiovascular disease and death.
Lead study author Dr Emily Szmuilowicz, an endocrinologist at Northwestern, told the press that:
"Our research found that despite previous reports suggesting that menopause symptoms were associated with increased levels of risk markers for heart disease, such as blood pressure and cholesterol, the actual outcomes tell a different story."
She said hot flashes "will never be enjoyable, but perhaps these findings will make them more tolerable".
Szmuilowicz co-chaired the study with Drs JoAnn Manson and Ellen Seely, from Harvard Medical School. They and the rest of the team used data from the Women's Health Initiative Observational Study, covering 60,027 post-menopausal women who were followed for 10 years.
As they were interested in links between timing of menopause symptoms and risk of cardiovascular events and death from all causes, they put the participants into four categories:
- No symptoms at start of menopause, nor at time of enrollment in the Study (the reference group, 18,799 women).
- Symptoms at start of menopause but not at Study enrollment (the "early symptoms" group, 24,753 women).
- Symptoms at both start of menopause and also at Study enrollment (the "persistent symptoms" group, 15,084 women).
- Symptoms started after menopause and were present at Study enrollment (the "late symptoms" group, 1,391 women).
Hazard ratio (and 95% confidence intervals CIs) for early symptoms compared to reference group for major coronary heart disease was 0.94 (0.84-1.06); for stroke it was 0.83 (0.72-0.96), for total cardiovascular disease it was 0.89 (0.81-0.97), and for death from all causes it was 0.92 (0.85-0.99).
However, for women whose symptoms began late during menopause, it was a different story: they had a higher risk of heart disease, stroke, total cardiovascular disease, and death from all causes, compared to women who had no symptoms at all.
Hazard ratio (95% CIs) for late symptom women compared to reference group for major coronary heart disease was 1.32 (1.01- 1.71), for stroke it was 1.14 (0.82-1.59), for total cardiovascular disease it was 1.23 (1.00-1.52), and for death from all causes it was 1.29 (1.08-1.54).
There were no significant links with any of these risks for the women whose symptoms persisted from the start of the menopause, compared to the reference group of women who had no symptoms at all.
Some scientists propose that because menopausal symptoms arise from instability in the blood vessels in the skin, it means they also cause problems in other blood vessels, such as those that affect the heart and feed the brain.
This study may cause them to question that idea.
The researchers said that because of the difference in the findings, depending on whether menopause symptoms started early or late, it could be that different pathophysiological mechanisms underly the links with cardiovascular disease.
They said further research was needed to look for these mechanisms, and warned that this difference could also signify that the predictive value of symptoms for cardiovascular risk may depend on when they start during the menopause.
"Vasomotor symptoms and cardiovascular events in postmenopausal women."
Szmuilowicz, Emily D.; Manson, JoAnn E.; Rossouw, Jacques E.; Howard, Barbara V.; Margolis, Karen L.; Greep, Nancy C.; Brzyski, Robert G.; Stefanick, Marcia L.; O'Sullivan, Mary Jo; Wu, Chunyuan; Allison, Matthew; Grobbee, Diederick E.; Johnson, Karen C.; Ockene, Judith K.; Rodriguez, Beatriz L.; Sarto, Gloria E.; Vitolins, Mara Z.; Seely, Ellen W.
Menopause, Published online ahead of print, 19 February 2011
Additional source: Northwestern Memorial Hospital (press release, 24 Feb 2011).
Written by: Catharine Paddock, PhD