title: Associations between particulate sulfate and organic carbon exposures and heart rate variability in patients with or at risk for cardiovascular diseases.
abstract: OBJECTIVE
  It is still unknown whether specific components in fine particles are associated with heart rate variability (HRV) reduction.
  
  
  METHODS
  We recruited 46 patients with or at risk for cardiovascular diseases to measure 24-hour HRV by ambulatory electrocardiographic monitoring. Fixed-site air-monitoring stations were used to represent participants' exposures to particles with aerodynamic diameters less than 10 microm (PM 10) and 2.5 microm (PM2.5), and particulate components of sulfate, nitrate, organic carbon (OC) and elemental carbon, and gaseous pollutants.
  
  
  RESULTS
  We found that HRV reduction was associated with sulfate, OC, and PM2.5 but not with the other five pollutants in single-pollutant models. Sulfate was found to remain in significant association with HRV reduction adjusting for OC and PM2.5 in three-pollutant models.
  
  
  CONCLUSIONS
  Exposures to sulfate and OC in PM2.5 were associated with HRV reduction in patients with or at risk for cardiovascular diseases.
authors.affiliation: Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan.
authors.forename: Kai-Jen
authors.initials: KJ
authors.lastname: Chuang
authors.forename: Chang-Chuan
authors.initials: CC
authors.lastname: Chan
authors.forename: Ta-Chen
authors.initials: TC
authors.lastname: Su
authors.forename: Lian-Yu
authors.initials: LY
authors.lastname: Lin
authors.forename: Chung-Te
authors.initials: CT
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002244:Carbon / Q000009:adverse effects* / Q000032:analysis; D002318:Cardiovascular Diseases / Q000139:chemically induced*; D004562:Electrocardiography; D005260:Female; D006304:Health Status; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis; D012306:Risk; D013431:Sulfates / Q000009:adverse effects* / Q000032:analysis; D013624:Taiwan
chemical_list: D052638:Particulate Matter; D013431:Sulfates; D002244:Carbon