Hot flashes in the late reproductive years: Risk factors for African American and Caucasian women

Hot flashes are a primary reason that midlife women seek medical care, but there is little information about the onset or the predictors of hot flashe s in the years before the menopause. This study examines women's experience of hot flashes in the late reproductive years, comparing African American and Caucasian women, and identifies hormonal, behavioral, and environmental risk factors for hot flashes associated with ovarian aging. Data are from a population-based prospective cohort study of ovarian aging in women who w ere ages 35-47, in general good health, and had regular menstrual cycles at study enrollment. Hot flashes were assessed by subject report in a structu red interview at the first follow-up period and correlated highly with prev ious prospective daily ratings of hot flashes (p = 0.0001). Blood samples w ere obtained in the first 6 days of the menstrual cycle in two consecutive cycles at enrollment and two consecutive cycles at follow-up. Predictor var iables include hormone measures, structured interview, and standard questio nnaire data. Thirty-one percent of the sample (n = 375) reported hot flashe s (mean age 41 years). In bivariate analysis, more African American than Ca ucasian women reported hot flashes (38% vs. 25%, p = 0.01). Significant pre dictors of hot flashes in the final multivariable logistic regression model were higher follicle-stimulating hormone (FSH) levels (odds ratio [OR] 3.1 9), anxiety (OR 1.06), baseline menopausal symptoms (OR 4.91), alcohol use (OR 1.09), body mass index (BMI) (OR 1.04), and parity (OR 1.20). Race did not predict hot flashes after adjusting for these variables. Hot flashes co mmonly occur before observable menstrual irregularities in the perimenopaus e and are associated with both hormonal and behavioral factors. The associa tion of hot flashes with increased body mass (BMI) challenges the current " thin" hypothesis and raises important questions about the role of BMI in ho rmone dynamics in the late reproductive years.