||Objective: Hot flashes are experienced by most midlife women. Emerging data indicate that they may be
associated with endothelial dysfunction. No studies have tested whether hot flashes are associated with endothelial
function using physiologic measures of hot flashes. We tested whether physiologically assessed hot flashes were
associated with poorer endothelial function. We also considered whether age modified associations.
Methods: Two hundred seventy-two nonsmoking women reporting either daily hot flashes or no hot flashes,
aged 40 to 60 years, and free of clinical cardiovascular disease, underwent ambulatory physiologic hot flash and
diary hot flash monitoring; a blood draw; and ultrasound measurement of brachial artery flow-mediated dilation to
assess endothelial function. Associations between hot flashes and flow-mediated dilation were tested in linear
regression models controlling for lumen diameter, demographics, cardiovascular disease risk factors, and estradiol.
Results: In multivariable models incorporating cardiovascular disease risk factors, significant interactions by age
(P<0.05) indicated that among the younger tertile of women in the sample (age 40-53 years), the presence of hot
flashes (beta [standard error]¼2.07 [0.79], P¼0.01), and more frequent physiologic hot flashes (for each hot flash:
beta [standard error]¼0.10 [0.05], P¼0.03, multivariable) were associated with lower flow-mediated dilation.
Associations were not accounted for by estradiol. Associations were not observed among the older women (age 54-60
years) or for self-reported hot flash frequency, severity, or bother. Among the younger women, hot flashes explained
more variance in flow-mediated dilation than standard cardiovascular disease risk factors or estradiol.
Conclusions: Among younger midlifewomen, frequent hot flasheswere associatedwith poorer endothelial function
and may provide information about women’s vascular status beyond cardiovascular disease risk factors and estradiol.