Body mass, estrogen levels, and hot flashes in midlife women

Objective: This study was undertaken to determine whether body mass index (BMI) is associated with hot flashes and whether the mechanism by which BMI increases the risk of hot flashes is by lowering estrogen levels. Study design: A case-control study was conducted among midlife women to examine risk factors for hot flashes. Cases were women who reported 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 for estrogen measurement. Results: Compared with normal weight women, very obese women had significantly higher odds of hot flashes. The odds ratios remained elevated although attenuated when the hormone variables were added to the model. Conclusion: These results indicate that very obese women are at increased risk for hot flashes compared with normal weight women. Estrogen levels may partly explain this relationship; however, other mechanisms appear to be involved as well.