Background: Although eastern Asian countries are exposed to high levels of air pollution, the impact of long-term exposures to fine particulate matter (PM2.5) air pollution on all-cause and cardiovascular mortality is not well identified. We assessed the relationship between long-term PM2.5 exposure and all-cause/cardiovascular mortalities. Methods: We included 436,933 subjects who received national health examinations from the Korean National Health Insurance Service-based National Sample Cohort. We matched subjects’ residential-address areas with hourly-measurements of PM2.5 concentration data. We estimated the risk of mortality with average PM2.5 exposure during the study period using a Cox proportional-hazards model. Results: During 1,683,271 person·years, all-cause and cardiovascular mortalities were observed in 6432 and 1603 subjects (382 and 95 per 100,000 person·years, respectively). An increase in 10 μg/m3 in PM2.5 was associated with increases in all-cause and cardiovascular mortalities by 3.4 % [2.7–4.1] and 4.7 % [3.6–5.8], respectively (each p < 0.001). PM2.5 was linearly and significantly correlated with these all-cause and cardiovascular mortalities above 18 μg/m3 of PM2.5 (p < 0.001), but it was not significant below 18 μg/m3 of PM2.5. To investigate the specific PM2.5 concentration for raising cardiovascular mortality more, we analyzed the sensitivities/specificities for different PM2.5 levels, and 18 μg/m3 showed the highest Youden's index (sensitivity + specificity-1) with c-index of 0.85 (0.84–0.86). PM2.5 effect on all-cause mortality was more profound in subjects with previous myocardial infarction compared to the opposite population. Conclusions: In the Korean general population exposed to high-air pollution, long-term PM2.5 exposure was linearly associated with increased risk for all-cause and cardiovascular mortality, especially above 18 μg/m3 of PM2.5.
Bibliographical noteFunding Information:
This study was supported by a research grant from the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology ( 2010-0021993 , NRF-2012R1A2A2A02045367 , NRF-2017R1A2B3003303 ), and grants from the Korean Healthcare Technology R&D project funded by the Ministry of Health & Welfare ( HI16C0058 , HI15C1200 ). As a medical writer, IS K wrote this manuscript without any grants. Appendix A
© 2020 Japanese College of Cardiology
All Science Journal Classification (ASJC) codes
- Cardiology and Cardiovascular Medicine