Self-Rated Health Status and Risk of Incident Stroke in 0.5 Million Chinese Adults: The China Kadoorie Biobank Study

Abstract

Background and purpose: Self-rated health (SRH) is a consistent and strong predictor of all-cause and cardiovascular mortality in various populations. However, the associations between SRH measures and risk of first-ever or recurrent stroke were rarely explored. We thus aim to prospectively investigate the associations between SRH measures and risk of total and subtypes of stroke in Chinese population.

Methods: A total of 494,113 participants from the China Kadoorie Biobank without prior heart diseases or cancer (486,541 without stroke and 7,572 with stroke) were followed from baseline (2004 to 2008) until December 31, 2013. General and age-comparative SRH were obtained from baseline questionnaires. First-ever stroke or recurrent events were ascertained through linkage to disease registry system and health insurance data.

Results: We identified 27,662 first-ever stroke and 2,909 recurrent events during an average of 7.0 years of follow-up. Compared with excellent general SRH, the hazard ratios (HRs) and 95% confidence intervals (CIs) for first-ever stroke associated with good, fair, and poor general SRH were 1.04 (1.00 to 1.08), 1.19 (1.15 to 1.23), and 1.49 (1.42 to 1.56) in the multivariate model, respectively. Compared with better age-comparative SRH, the HRs (95% CIs) of same and worse age-comparative SRH were 1.13 (1.10 to 1.17) and 1.51 (1.45 to 1.58), respectively. The relations of SRH measures with ischemic stroke, hemorrhagic stroke, and recurrent stroke were similar to that with total first-ever stroke. However, the magnitude of associations was much stronger for fatal stroke than for non-fatal stroke.

Conclusions: This large-scale prospective cohort suggests that self-perceived health status is associated with incident stroke, regardless of stroke subtype.

Keywords: Health status; Prospective studies; Stroke.

Figure 1.

Survival and recurrence-free curves for participants according to self-rated health (SRH) categories. (A) First-ever stroke-free survival curves stratified by general SRH. (B) First-ever stroke-free survival curves stratified by age-comparative SRH. (C) Recurrence-free survival curves stratified by general SRH. (D) Recurrence-free survival curves stratified by age-comparative SRH. All survival curves were stratified by age (5 years intervals), sex, region (10 areas) and adjusted for age (continuous), marital status, education, annual household income, occupation, healthcare coverage, housing condition, menopausal status, sleep problems, cigarette smoking, alcohol drinking, physical activity (continuous), body mass index (continuous), family history of stroke, presence of baseline major depressive episodes, diabetes, hypertension, and other prevalent diseases (yes, no). The categories and definitions of all categorical variables were illustrated in the ‘Covariates’ section of the Methods.

Figure 2.

Stratified analysis: poor versus excellent general self-rated health and risk of first-ever stroke. The hazard ratios and 95% confidence intervals were calculated after stratification by age (5 years intervals), sex, region (10 areas) and adjustment for age (continuous), marital status, education, annual household income, occupation, healthcare coverage, housing condition, menopausal status, sleep problems, cigarette smoking, alcohol drinking, physical activity (continuous), body mass index (BMI) (continuous), family history of stroke, presence of baseline major depressive episodes, diabetes, hypertension, and other prevalent diseases (yes, no). The categories and definitions of all categorical variables were illustrated in the ‘Covariates’ section of the Methods. ^*P_interaction <0.05.