Limited evidence exists for long-term
effects of PM2.5 constituents on mortality. Hence, we aimed
to assess associations
between all-cause mortality and long-term exposure to PM2.5 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 PM2.5 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/m3) rise in exposure to PM2.5. Comparable or stronger
associations were found among PM2.5 constituents with the
mortality risk increased by 11.3–14.1% per IQR increase in
exposure concentrations. After adjustment for the collinearity between
total PM2.5 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 PM2.5 constituents. This
cohort study added the novel longitudinal evidence for elevated mortality
linked with long-term exposure to PM2.5 constituents among
Chinese adults.