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Risk of long-term hot flashes after natural menopause: evidence from the Penn Ovarian Aging Study cohort

Freeman, Ellen W. PhD1,2; Sammel, Mary D. ScD3; Sanders, Richard J. MS4

doi: 10.1097/GME.0000000000000196
Original Articles

Objective This study aims to estimate the risk of hot flashes relative to natural menopause and to evaluate the associations of hormone levels, behavioral variables, and demographic variables with the risk of hot flashes after menopause.

Methods We performed annual assessment of 255 women who were premenopausal at baseline and reached natural menopause within 16 years of follow-up.

Results The prevalence of moderate/severe hot flashes increased in each premenopausal year, reaching a peak of 46% in the first 2 years after the final menstrual period (FMP). Hot flashes decreased slowly after menopause and did not return to premenopausal levels until 9 years after the FMP. The mean (SD) duration of moderate/severe hot flashes after the FMP was 4.6 (2.9) years (for any hot flashes, 4.9 [3.1] y). One third of women at 10 years or more after menopause continued to experience moderate/severe hot flashes. African-American women (obese and nonobese) and obese white women had significantly greater risks of hot flashes compared with nonobese white women (interaction, P = 0.01). In multivariable analysis, increasing follicle-stimulating hormone levels before the FMP (P < 0.001), decreasing estradiol (odds ratio, 0.87; 95% CI, 0.78-0.96; P = 0.008), and increasing anxiety (odds ratio, 1.05; 95% CI, 1.03-1.06; P < 0.001) were significant risk factors for hot flashes, whereas higher education levels were protective (odds ratio, 0.66; 95% CI, 0.47-0.91; P = 0.011).

Conclusions Moderate/severe hot flashes continue, on average, for nearly 5 years after menopause; more than one third of women observed for 10 years or more after menopause have moderate/severe hot flashes. Continuation of hot flashes for more than 5 years after menopause underscores the importance of determining individual risks/benefits when selecting hormone or nonhormone therapy for menopausal symptoms.

From the Departments of 1Obstetrics and Gynecology and 2Psychiatry, and Centers for 3Clinical Epidemiology and Biostatistics and 4Research in Reproduction and Women’s Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

Received October 24, 2013; revised and accepted November 26, 2013.

Funding/support: This study was supported by National Institutes of Health grants RO1 AG12745 (to E.W.F., principal investigator) and UL1TR000003 (to the Clinical and Translational Research Center, Perelman School of Medicine, University of Pennsylvania).

Financial disclosure/conflicts of interest: In the past 12 months, E.W.F. received a grant (paid to the University of Pennsylvania) from Forest Research Inc. The other authors declare no conflicts of interest.

Address correspondence to: Ellen W. Freeman, PhD, Suite 820 (Mudd), 3701 Market Street, Philadelphia, PA 19104. E-mail:

© 2014 by The North American Menopause Society.