Serum leptin levels, hormone levels, and hot flashes in midlife women.

Objective: To examine the associations between serum leptin levels, sex steroid hormone levels, and hot flashes in normal weight and obese midlife women.

Design: Cross-sectional study.

Setting: University clinic.

Patient(s): 201 Caucasian, nonsmoking women aged 45 to 54 years with a body mass index of <25 kg/m2 or >or=30 kg/m2.

Intervention(s): Questionnaire, fasting blood samples.

Main Outcome Measure(s): Serum leptin and sex steroid hormone levels.

Result(s): Correlation and regression models were performed to examine associations between leptin levels, hormone levels, and hot flashes. Leptin levels were associated with BMI, with "ever experiencing hot flashes" (questionnaire), with hot flashes within the last 30 days, and with duration of hot flashes (>1 year, P=.03). Leptin was positively correlated with testosterone, free testosterone index, and free estrogen index and inversely associated with levels of sex hormone-binding globulin. In women with a body mass index>or=30 kg/m2, leptin levels no longer correlated with testosterone levels.

Conclusion(s): Serum leptin levels are associated with the occurrence and duration of hot flashes in midlife women; however, no correlation was found between leptin and serum estradiol.