Duration of Menopausal Hot Flushes and Associated Risk Factors

OBJECTIVE: To estimate the duration of moderate-to-severe menopausal hot flushes and identify potential risk factors for hot flush duration. METHODS: The Penn Ovarian Aging Study cohort was monitored for 13 years. Hot flushes were evaluated at 9-month to 12-month intervals through in-person interviews. The primary outcome was the duration of moderate-to-severe hot flushes estimated by survival analysis (n=259). Potential risk factors included menopausal stage, age, race, reproductive hormone levels, body mass index (BMI), and current smoking. A secondary analysis included women who reported any hot flushes (n=349). RESULTS: The median duration of moderate-to-severe hot flushes was 10.2 years and was strongly associated with menopausal stage at onset. Hot flushes that started near entry into the menopause transition had a median duration greater than 11.57 years; onset in the early transition stage had a median duration of 7.35 years (95% confidence interval [CI] 4.94-8.89; P<.001); and onset in the late transition to postmenopausal stages had a median duration of 3.84 years (95% CI 1.77-5.52; P<.001). The most common ages at onset of moderate-to-severe hot flushes were 45-49 years (median duration, 8.1 years; 95% CI 5.12-9.28). African American women had a longer duration of hot flushes than white women in adjusted analysis. CONCLUSION: The median duration of hot flushes considerably exceeded the time-frame that is generally accepted in clinical practice. The identified risk factors, particularly menopausal stage, race, and BMI, are important to consider in individualizing treatment and evaluating the risk-to-benefit ratio of hormones and other therapies. (Obstet Gynecol 2011; 117: 1095-1104) DOI: 10.1097/AOG.0b013e318214f0de