Obesity, smoking, and risk of vasomotor menopausal symptoms: a pooled analysis of eight cohort studies

• Published in: American journal of obstetrics and gynecology 2020-05, Vol.222 (5), p.478.e1-478.e17
• Main Authors: Anderson, Debra J., Chung, Hsin-Fang, Seib, Charrlotte A., Dobson, Annette J., Kuh, Diana, Brunner, Eric J., Crawford, Sybil L., Avis, Nancy E., Gold, Ellen B., Greendale, Gail A., Mitchell, Ellen S., Woods, Nancy F., Yoshizawa, Toyoko, Mishra, Gita D.
• Format: Article
• Language: English
• Subjects: Body Mass Index; Female; Hot Flashes - etiology; Hot Flashes - physiopathology; hot flushes; Humans; Menopause - physiology; Middle Aged; night sweats; obesity; Obesity - complications; Obesity - physiopathology; overweight; smoking; Smoking - adverse effects; Smoking - physiopathology; Sweating - physiology; vasomotor symptoms; Vasomotor System - physiopathology
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1016/j.ajog.2019.10.103

Frequent and severe vasomotor symptoms during menopause are linked with adverse health outcomes. Understanding modifiable lifestyle factors for the risk of vasomotor menopausal symptoms is important to guide preventive strategies. We investigated the associations between body mass index and smoking, their joint effects with the risk of vasomotor symptoms, and whether the associations differed by menopausal stage. The International Collaboration for a Life Course Approach to Reproductive Health and Chronic Disease Events pooled data on 21,460 midlife women from 8 studies (median age, 50 years; interquartile range, 49–51 years) for the cross-sectional analysis. Four studies provided data for the prospective analysis (n=11,986). Multinomial logistic regression models with 4 categories of frequency/severity for the outcome of vasomotor symptoms were used to estimate relative risk ratios and 95% confidence intervals that were adjusted for within-study correlation and covariates. At baseline, nearly 60% of the women experienced vasomotor symptoms. One-half of them were overweight (30%) or obese (21%), and 17% were current smokers. Cross-sectional analyses showed that a higher body mass index and smoking more cigarettes with longer duration and earlier initiation were all associated with more frequent or severe vasomotor symptoms. Never smokers who were obese had a 1.5-fold (relative risk ratio, 1.52; 95% confidence interval, 1.35–1.73) higher risk of often/severe vasomotor symptoms, compared with never smokers who were of normal-weight. Smoking strengthened the association because the risk of often/severe vasomotor symptoms was much greater among smokers who were obese (relative risk ratio, 3.02; 95% confidence interval, 2.41–3.78). However, smokers who quit at