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

Abstract

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.

Figure 1

Flowchart of inclusion and exclusion of study participants.

Figure 2

Hazard ratios (HRs) for stroke by age at menarche, age at menopause, and reproductive lifespan among women. Model A1, model B1, and model C1: adjusted for age at recruitment. Model A2, model B2, and model C2: model A1, model B1, and model C1 plus region, marital status, body mass index, education level, alcohol drinking, smoking, comorbidity, pharmacological treatment, family history of stroke. Model A3: model A2 plus menstrual status, contraceptive use status, and breastfeeding experience, parity; Model B3: model B2 plus age at menarche, reproductive lifespan, contraceptive use status, and breastfeeding experience, parity; Model C3: model C2 plus age at menarche, age at menopause, contraceptive use status, and breastfeeding experience, parity.

Figure 3

Adjusted hazard ratios (HRs) for stroke per year by age at menarche, age at menopause, and reproductive lifespan within various subgroups. Panel A. Adjusted HRs for age at menarche. Panel B. Adjusted HRs for age at menopause. Panel C. Adjusted HRs for reproductive lifespan. Model A were adjusted for age at recruitment, region, marital status, body mass index, education level, alcohol drinking, smoking, comorbidity, pharmacological treatment, family history of stroke, menstrual status, contraceptive use status, and breastfeeding experience, parity. Model B were adjusted for age at recruitment, region, marital status, body mass index, education level, alcohol drinking, smoking, comorbidity, pharmacological treatment, family history of stroke, age at menarche, reproductive lifespan, contraceptive use status, and breastfeeding experience, parity. Model C were adjusted for age at recruitment, region, marital status, body mass index, education level, alcohol drinking, smoking, comorbidity, pharmacological treatment, family history of stroke, age at menarche, age at menopause, contraceptive use status, and breastfeeding experience, parity.