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Cohort evidence linking long-term survival of older adults with exposure to fine particulate matter (PM2.5) constituents remains scarce in China. By constructing a dynamic cohort based on the Chinese Longitudinal Healthy Longevity Study, we aimed to assess the individual and joint associations of major PM2.5 constituents with all-cause death in Chinese oldest-old (.80 years) adults. Time-dependent Cox proportional hazards models were adopted to estimate death risks of long-term exposure to PM2.5 constituents. Among 14,884 participants, totaling 56,342 person-years of follow-up, 12,346 deaths were identified. The highest mortality risk associated with an interquartile range (IQR) increase in exposure was 1.081 (95% confidence interval [CI]: 1.055–1.108) for sulfate (IQR=4.1 μg m-3), followed by 1.078 (95% CI: 1.056–1.101) for black carbon (IQR=1.6 μg m-3), 1.056 (95% CI: 1.028–1.084) for ammonium (IQR=3.2 μg m-3), 1.050 (95% CI: 1.021–1.080) for nitrate (IQR=5.8 μg m-3), and 1.049 (95% CI: 1.024–1.074) for organic matter (IQR=10.3 μg m-3). In joint exposure, each IQRequivalent rise of all five PM2.5 constituents was associated with an 8.2% (95% CI: 4.0%–12.6%) increase in mortality risk. The weight analysis indicated the predominant role of sulfate and black carbon in driving PM2.5-related mortality. Octogenarians (aged 80–89 years) and rural dwellers were at significantly greater risk of mortality from individual and joint exposures to PM2.5 constituents. This study suggests that later-life exposure to PM2.5 constituents, particularly sulfate and black carbon, may curtail long-term survival of the oldest-old in China. [ABSTRACT FROM AUTHOR]

Limited evidence exists for long-term effects of PM 2.5 constituents on mortality. Hence, we aimed to assess associations between all-cause mortality and long-term exposure to PM 2.5 constituents in China. We designed a nationwide cohort study of 30524 adults from 162 prefectural areas across mainland China with follow-ups through years 2010-2017. Cox proportional hazards models with time-varying exposures were employed to quantify associations between all-cause mortality and long-term exposure to PM 2.5 and constituents. A total of 1210 deaths occurred during 172297.7 person-years. A multiadjusted Cox model estimated an hazard ratio (HR) of 1.125 (95% confidence interval: 1.058-1.197) for all-cause mortality, associated with an interquartile range (IQR = 26.7 μg/m 3 ) rise in exposure to PM 2.5 . Comparable or stronger associations were found among PM 2.5 constituents with the mortality risk increased by 11.3-14.1% per IQR increase in exposure concentrations. After adjustment for the collinearity between total PM 2.5 and constituents, effect estimates for nitrate, ammonium, and sulfate remained significant and became larger. Urban residents, alcohol drinkers, smokers, and men were more susceptible to chronic impacts from ambient PM 2.5 constituents. This cohort study added the novel longitudinal evidence for elevated mortality linked with long-term exposure to PM 2.5 constituents among Chinese adults.