A menopausal woman often tells her doctor that she is suffering from
vasomotor symptoms, but it is far less often that her doctor wonders whether
these symptoms represent anything more than a quality of life issue.
Yet emerging evidence raises questions about whether vasomotor symptoms
are more than just a nuisance. Some have hypothesized that the peripheral
vasomotor instability typical of hot flashes may herald underlying
abnormalities in systemic vascular function. Since hot flashes occur in the
vast majority of women during the menopausal transition, there has been
increasing interest in elucidating whether or not the presence of vasomotor
symptoms may have health implications beyond their impact on a woman’s
quality of life.
A growing body of literature suggests that cardiovascular disease risk
factors may differ in women with vs. without vasomotor symptoms. On the one
hand, some traditional CVD risk factors may predispose women to vasomotor
Women who smoke are more likely to experience hot flashes, and obesity
has been postulated to increase the risk of hot flashes through impaired heat
dissipation (in spite of the classic association of obesity with increased
peripheral conversion of androgens to estrogens in fat tissue). On the other
hand, several recent studies suggest that the converse may be true as well.
That is, vasomotor symptoms may be independently associated with an adverse CV
risk profile as assessed by surrogate CVD risk markers. A number of small
studies have reported increased ambulatory blood pressure in women with
self-reported vasomotor symptoms. A large observational study from the
Netherlands showed higher systolic and diastolic BP as well as cholesterol
levels in perimenopausal women with vasomotor symptoms compared to their
counterparts without, even after controlling for relevant confounders. An
analysis of data from the Study of Women’s Health Across the Nation (SWAN)
showed that hot flashes were associated with an increased risk of subclinical
CVD (impaired endothelial function and increased aortic calcification),
independent of CV risk factors. Furthermore, in a post hoc analysis of the
Women’s Health Initiative Hormone Therapy clinical trials, the increased
CVD risk with hormone therapy observed with increasing time since menopause was
largely noted among the women who reported moderate or severe vasomotor
These associations between vasomotor symptoms and increased CVD risk
raise interesting questions about whether these symptoms may signal an
underlying predisposition towards systemic vascular dysfunction beyond the
peripheral vasomotor instability characteristic of hot flashes. Yet the studies
published to date do not shed light on whether the presence of vasomotor
symptoms is associated with an increased risk of clinical CVD events. Further,
as one cannot be randomized to vasomotor symptoms, the observational nature of
all of these studies leaves many unanswered questions about the degree to which
residual confounding may cloud these associations.
Similarly, the intricate relationships between vasomotor symptoms and HT
use, which is now well-known to impact CVD risk, complicate interpretation of
these findings. Future studies will need to disentangle the complex
relationships between vasomotor symptoms, CVD risk and HT use. As vasomotor
symptoms occur in the majority of perimenopausal women, as well as in a
substantial minority of older postmenopausal women, these studies will be
awaited with interest. Until then, we are left wondering whether hot flashes
are a just a symptom or also a signal of something bigger.
Emily D. Szmuilowicz, MD, is an Instructor of Clinical Medicine at
Northwestern University and a member of the Endocrine Today Editorial Board.
For more information:
- Gast GC, Grobbee DE, Pop VJM, et al. Menopausal complaints are
associated with cardiovascular risk factors. Hypertension.
- Rossouw JE, Prentice RL, Manson JE, et al. Postmenopausal hormone
therapy and risk of cardiovascular disease by age and years since
menopause. JAMA. 2007;297:1465-1477.
- Thurston RC, Sutton-Tyrrell K, Everson-Rose SA, et al. Hot flashes
and subclinical cardiovascular disease. Findings from the Study of Women’s
Health Across the Nation Heart Study. Circulation.