Long-term fine particulate matter exposure and cardiovascular mortality in the general population: a nationwide cohort study.
J Cardiol. 2019 Dec 13. Epub 2019 Dec 13. PMID: 31839460
BACKGROUND: Although eastern Asian countries are exposed to high levels of air pollution, the impact of long-term exposures to fine particulate matter (PM) air pollution on all-cause and cardiovascular mortality is not well identified. We assessed the relationship between long-term PMexposure 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 PMconcentration data. We estimated the risk of mortality with average PMexposure 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/min PMwas 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). PMwas linearly and significantly correlated with these all-cause and cardiovascular mortalities above 18 μg/mof PM(p < 0.001), but it was not significant below 18 μg/mof PM. To investigate the specific PMconcentration for raising cardiovascular mortality more, we analyzed the sensitivities/specificities for different PMlevels, and 18 μg/mshowed the highest Youden's index (sensitivity + specificity-1) with c-index of 0.85 (0.84-0.86). PMeffect 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 PMexposure was linearly associated with increased risk for all-cause and cardiovascular mortality, especially above 18 μg/mof PM.