Individual and mixed associations between fine particulate matter components and hospital admissions for hypertension: Insights from a large-scale South Chinese cohort study

Abstract

<p>Fine particulate matter (PM2.5) pollution threatens urban sustainability. Few cohort studies have assessed hypertension risks linked to lagged and cumulative exposure to PM2.5 components. Using data from a cohort study of 36,271 individuals in South China (2015–2020), we examined the individual associations between time-varying PM2.5 and six components (NO3−, SO42−, BC, CL−, NH4+, and OM) with hypertension hospitalization through Cox proportional hazards regression. Mixed associations of simultaneous exposure to these components were analyzed at lag 0, lag 1, lag 2, lag 0–1, and lag 0–2 years using quantile-based g-computation models. Individual-effect analysis revealed strong associations, with each quantile increase in CL−, NH4+, SO42−, and NO3− linked to 17 %–32 % higher hypertension risks across different time windows. Co-exposure to PM2.5 components at different lag times increased hospital admissions for overall hypertension, with hazard ratios (95 % confidence intervals) of 1.151 (1.136–1.166), 1.221 (1.205–1.238), 1.257 (1.241–1.273), 1.087 (1.073–1.101), and 1.197 (1.182–1.212). Secondary water-soluble ions (NO3−, SO42−, NH4+, CL−) were major contributors. Increased susceptibility was observed among those under 45, men, individuals with lower education, unhealthy weight, or limited green space exposure. These findings highlight the lagged and cumulative impacts of simultaneous exposure to PM2.5 component on hypertension.</p>