Social Determinants of Health, Blood Pressure Classification, and Incident Stroke Among Chinese Adults

Importance: Although cumulative evidence suggests that higher blood pressure (BP) and a greater burden of social determinants of health (SDOH) are associated with an increased risk of stroke, few studies have examined whether SDOH burden modifies the association between BP and stroke risk. Objective: To evaluate whether the association between BP classification and stroke risk differs by SDOH burden among Chinese adults. Design, Setting, and Participants: In this cohort study, analyses were conducted among 90 850 participants in the prospective subcohort of the China Patient-Centered Evaluative Assessment of Cardiac Events Million Persons Project, with recruitment from January 1, 2016, to December 31, 2020. Participants without cardiovascular diseases and with complete data were included and followed up for stroke events until June 30, 2023. Exposures: Social determinants of health burden was defined using 5 components: educational attainment, economic stability, health care access, social support, and urban vs rural residence. Blood pressure was categorized according to the 2017 American College of Cardiology/American Heart Association BP guideline. Main Outcomes and Measures: Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs for associations of BP classification with incident stroke stratified by SDOH burden groups. Results: The study included 90 850 participants (median age, 54.0 years [IQR, 46.0-62.0 years]; 55 390 women [61.0%]). During a median follow-up of 5.0 years (IQR, 4.1-5.8 years), 4408 incident stroke events were recorded. Compared with normal BP, elevated BP (HR, 1.33 [95% CI, 1.17-1.52]), stage 1 hypertension (HR, 1.60 [95% CI, 1.43-1.78]), and stage 2 hypertension (HR, 1.79 [95% CI, 1.61-2.00]) were associated with stroke among participants with high SDOH burden, while only stage 2 hypertension (HR, 1.52 [95% CI, 1.20-1.93]) was associated with stroke among those with low SDOH burden, with a significant multiplicative interaction of SDOH burden and BP classification (P = .03). Participants with high SDOH burden and stage 2 hypertension had the highest risk of stroke compared with participants with low SDOH burden and normal BP (HR, 2.13 [95% CI, 1.75-2.60]). Conclusions and Relevance: This study suggests that higher BP levels, even at lower stages of hypertension, pose a greater stroke risk for individuals with high SDOH burden. Early surveillance and intervention for high BP should be emphasized in socioeconomically disadvantaged populations.