Cigarette smoking, estrogen levels, and hot flashes in midlife women

The aims of this study were to examine the association of smoking with the occurrence, frequency, and severity of hot flashes and to determine whether the mechanism by which active cigarette smoking increases the risk of hot flashes is by lowering estradiol and estrone levels. A case–control study was conducted among women aged 45–54 years to examine risk factors for hot flashes. Cases were women who reported ever experiencing hot flashes ( n = 353). Controls were women who reported never experiencing hot flashes ( n = 258). Each participant completed a questionnaire and provided a blood sample that was used to measure estradiol and estrone levels. The results showed that both current and ever smokers had higher odds than never smokers of experiencing any and more severe hot flashes. Further, significant positive associations were observed between frequency and duration of smoking and the experiencing of any and more severe hot flashes. Smoking was not associated with estradiol or estrone levels in univariate analyses. In addition, the odds ratios for the associations between the cigarette smoking variables and hot flashes did not change when the hormone variables were added to the model. These findings indicate that smoking is associated with the occurrence of any and more severe hot flashes, independent of estrogen levels.