Ambient fine particulate matter pollution and years of life lost from cardiovascular diseases in 48 large Chinese cities: Association, effect modification, and additional life gain

Existing evidence on the associations between fine particulate matter (PM_2.5) and years of life lost (YLL) from cardiovascular diseases (CVD) is limited and inconclusive, and the role of potential modifiers, especially those at city-level, is not fully understood. In this study, a time-series study was conducted in 48 large Chinese cities from 2013 to 2017. Generalized additive model coupled with random effects model were used to estimate national-average associations of PM_2.5 with YLL. Effect modification by individual- and city-level characteristics obtained by linking with China Chronic Disease and Risk Factors Surveillance was explored. Moreover, additional life gain was evaluated under scenario where PM_2.5 concentration would be reduced. For 10 μg/m³ increase in PM_2.5 concentration at lag01 day, the relative increment of YLL was 0.22% from CVD, 0.20% from ischemic heart disease, 0.26% from stroke, 0.23% from hemorrhagic stroke, and 0.31% from ischemic stroke. Some associations were stronger in elder and less educated people, warm season, as well as cities characterized by higher temperature and prevalence of binge drinking and excess red meat intake, or lower PM_2.5 and prevalence of usual exercise. Additional life gain attributable to avoidable YLL from CVD was estimated to be 0.08 year if PM_2.5 concentration could fall to the standard recommended by World Health Organization (25 μg/m³). This large epidemiological investigation demonstrated robust evidence of short-term associations between PM_2.5 exposure and YLL from CVD. Potential modifiers should be considered to develop efficient intervention strategies. Implementation of more stringent standard is beneficial to alleviate YLL caused by PM_2.5.