Ambient sulfur dioxide and years of life lost from stroke in China: a time-series analysis in 48 cities

Background and objectives: Sulfur dioxide (SO2) is a ubiquitous air pollutant and its concentration in China remains at a higher level in the world. However, evidence regarding short-term effect of SO2 on years of life lost (YLL) from stroke is scarce. We aim to estimate the short-term association between SO2 pollution and YLL for stroke and the related excess life years and economic loss. Methods: A national time-series study was conducted in 48 Chinese cities from 2013 to 2017. Generalized additive model coupled with random-effects model were used to explore the effects of SO2 on YLL from stroke. Stratified analyses were performed by demographical and geographical factors, and the effect modification of city-level factors was estimated. In addition, the related economic loss was calculated using the method of the value per statistical life year (VSLY). Results: Averaged daily mean SO2 concentration was 27.1 mu g/m(3) in 48 Chinese cities from 2013 to 2017. Per 10 mu g/m(3) increase in the concentration of SO2 (lag03) was associated with an increment of 0.70% (95% confidence interval: 0.27%,1.13%), 0.51% (-0.01%,1.04%), 0.71% (0.14%,1.28%) increase in YLL from total stroke, hemorrhagic and ischemic stroke, respectively. The effect of short-term ambient SO2 exposure on YLL from stroke was more pronounced in the less-educated population and those living in the south. The corresponding excess economic loss during the study period due to SO2-related YLL from stroke accounted for 0.08% (0.03%, 0.13%) of the GDP in China. Conclusions: Our results provide evidence from China that short-term exposure to SO2 is positively associated with YLL from stroke and its major subtypes in certain subgroups of population. This study calls for greater awareness of the adverse health effect due to SO2 in China and other developing countries, as well as local-specific implementation of air pollution mitigation measures. (C) 2020 Elsevier Ltd. All rights reserved.