Association of age at menarche and menopause, reproductive lifespan, and stroke among Chinese women: Results from a national cohort study

Background The association between age of menarche, age of menopause, reproductive lifespan and risk of stroke in Chinese women remains unclear and requires further clarification. Methods A stratified multi-stage random sampling method was used to select participants at baseline in 2012-2015. The participants’ basic information was collected through a standardized questionnaire by professional investigator and examined by trained medical personnel. Follow-up was completed in 2019 to collect the stroke events. The Cox proportional hazards models were used to evaluate hazard ratios between reproductive factors and stroke risk. Results Overall, 11,256 women (5,155 non-menopausal women and 6,101 menopausal women) were included (mean [standard deviation] age, 55.2 [12.9] years). The risk was highest in women with menarche at age ≥17 years (HR, 1.290; 95%CI, 0.959∼1.733) and with reproductive lifespan ≤28 years (HR, 1.643; 95%CI, 1.041∼2.595). Age at menarche was positively associated with risk of stroke (HR, 1.086; 95%CI, 1.006∼1.172). There was a negative association between age at menopause and stroke risk in women with 2 live births (HR, 0.897; 95%CI, 0.834∼0.964). Reproductive lifespan was negatively associated with risk of stroke (HR, 0.963; 95%CI, 0.946∼1.027). Subgroup analysis also showed that association between age at menarche, reproductive lifespan and stroke events. Conclusions Chinese women with late age at menarche and shorter reproductive lifespan have higher risk of stroke according to a large prospective study.