title: Chronic exposure to particulate matter and risk of cardiovascular mortality: cohort study from Taiwan.
abstract: BACKGROUND
  Evidence on the association between long-term exposure to air pollution and cardiovascular mortality is limited in Asian populations.
  
  
  METHODS
  We conducted a cohort study on the association between fine particulate matter (PM2.5) and cardiovascular mortality using 43,227 individuals in a civil servants health service in Taiwan. Each participant was assigned an exposure level of particulate matter based on their district of residence using air pollution data collected by the Taiwan Environmental Protection Agency and with modeling using geographic information systems. The participants were followed up from 1989 to 2008 and the vital status was ascertained from death records. Cox regression models were used to adjust for confounding factors.
  
  
  RESULTS
  The district-level average of PM2.5 ranged from 22.8 to 32.9 μg/m(3) in the study area. After a median follow-up of 18 years, 1992 deaths from all causes including 230 cardiovascular deaths occurred. After adjustment for potential confounders, PM2.5 levels were not significantly associated with mortality from cardiovascular disease [Hazard Ratio (HR) 0.80; 95 % Confidence Interval (CI), 0.43 to 1.50 per 10 μg/m(3) increase in PM2.5] or all causes (HR 0.92; 95 % CI, 0.72 to 1.17 per 10 μg/m(3) increase in PM2.5). The results were similar when the analysis was restricted to the urban areas and when the PM2.5 measurement was changed from the period average (2000-2008) to annual average.
  
  
  CONCLUSIONS
  Our findings are different from those in prior cohort studies conducted in Asia where ambient air pollutionwas associated with an increased risk of cardiovascular mortality. The high background level of air pollutionin our study area and the small number of event cases limited the power of this study.
  
  
  CONCLUSIONS
  In this population-based cohort study in Taiwan, we found no evidence of increased risk for all-cause or cardiovascular mortality with long-term exposure to PM2.5.
authors.affiliation: Division of General Internal Medicine, Johns Hopkins University, Baltimore, MD, USA. etseng3@jhmi.edu.
authors.forename: Eva
authors.initials: E
authors.lastname: Tseng
authors.affiliation: Department of Public Health, China Medical University, Taichung City, Taiwan. wcho@mail.cmu.edu.tw.
authors.forename: Wen-Chao
authors.initials: WC
authors.lastname: Ho
authors.affiliation: Department of Public Health, China Medical University, Taichung City, Taiwan. u9656852@cmu.edu.tw.
authors.forename: Meng-Hung
authors.initials: MH
authors.lastname: Lin
authors.affiliation: Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei, Taiwan. tcheng@ntu.edu.tw.
authors.forename: Tsun-Jen
authors.initials: TJ
authors.lastname: Cheng
authors.affiliation: Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei, Taiwan. pchen@ntu.edu.tw.
authors.forename: Pau-Chung
authors.initials: PC
authors.lastname: Chen
authors.affiliation: Institute of Epidemiology and Preventive Medicine, National Taiwan University, 17 Xu-Zhou Road, Rm706, Taipei, 100, Taiwan. hsienho@ntu.edu.tw.
authors.forename: Hsien-Ho
authors.initials: HH
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000009:adverse effects*; D000397:Air Pollution / Q000009:adverse effects*; D002318:Cardiovascular Diseases / Q000401:mortality*; D015331:Cohort Studies; D003644:Death Certificates; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D052638:Particulate Matter / Q000009:adverse effects*; D016016:Proportional Hazards Models; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter