Association between reproductive span and postmenopausal metabolic syndrome: a cross-sectional study in China

The prevalence of metabolic syndrome(MS) among postmenopausal women is increasing, becoming a pressing public health issue. Despite extensive research, the precise etiology of MS in postmenopausal women remains unclear. There is a relative lack of research exploring the association between reproductive span and MS, and the conclusions were inconsistent. The aim of the present study is to investigate the relationship between reproductive span and MS in postmenopausal women.

A cross-sectional study was conducted using data from the 2015 follow-up of the China Health and Retirement Longitudinal Study (CHARLS). The data set included household questionnaire information, physical examination data, and blood test results for the respondents. Total sample size: 2,801. A multivariable logistic regression was used to analyze the relationship between reproductive span and MS in postmenopausal women in China.

As the age at menarche increased, the prevalence of obesity and high triglycerides decreased(P<0.05); as the age at menopause increased, the prevalence of hyperglycemia and hypertension increased(P<0.05); as the reproductive span extended, the prevalence of obesity, hypertension, and hyperglycemia all increased (P<0.05). After adjusting for age, body mass index, education level, smoking, alcohol consumption, number of meals per day, and sleep duration, the reproductive span remained statistically significant between the MS group and the non-MS group. When the reproductive span was treated as a continuous variable, the odds ratio (OR) was 1.019 (95% CI: 1.001-1.038), and the longer the reproductive span, the higher the odds of MS (P=0.042). The OR (95% CI) values for a reproductive span of 32 to 35 years and ≥36 years were 1.305 (95% CI: 1.077-1.581) and 1.381 (95% CI: 1.117-1.708), respectively, both of which were statistically significant (P<0.05).

The longer the reproductive span of postmenopausal women, the higher the prevalence of MS.