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 standardised questionnaire by professional investigator and examined by trained medical personnel. Follow-up was conducted in 2018-2020 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 (5155 non-menopausal women and 6101 menopausal women) were included (mean (x̄); standard deviation (SD) age = 55.2; 12.9 years). The risk was highest in women with menarche at age ≥17 years (hazard ratio (HR) = 1.290; 95% confidence interval (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 two 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.