Relation of Reproductive Lifespan with Obesity in Chinese Women: Results from a Large Representative Nationwide Population.

Background: Research on the association between age at menarche and menopause, reproductive lifespan, and the risk of obesity in China is unclear and requires further clarification. Materials and Methods: Data were obtained from the China Hypertension Survey, a cross-sectional study using a stratified multistage random sampling method, conducted from October 2012 to December 2016, with a total of 187,162 women included in the analysis. Logistic regression models and restricted cubic spines were used to estimate the relationship between obesity and age at menarche, age at menopause, and reproductive lifespan. Results: The mean (standard deviation) age at menarche and menopause, and reproductive lifespan were 15.5 (1.8), 48.7 (3.5), and 33.2 (3.9) years, respectively. Age at menarche was negatively related to the risk of obesity (odds ratio [OR]: 0.968; 95% confidence interval [CI]: 0.961-0.975). There was a positive association between age at menopause and the risk of obesity in postmenopausal women (OR: 1.019; 95% CI: 1.014-1.023). Reproductive lifespan was positively related to obesity (OR: 1.020; 95% CI: 1.017-1.025). The restricted cubic spines showed the association between age at menarche, age at menopause, reproductive lifespan, and obesity was nonlinear when fully adjusted. Conclusions: Based on the large nationally representative sample, Chinese women with earlier age at menarche, later age at menopause, and longer reproductive lifespan have a higher risk of obesity.