title: Association of heart rate variability in taxi drivers with marked changes in particulate air pollution in Beijing in 2008.
abstract: BACKGROUND
  Heart rate variability (HRV), a marker of cardiac autonomic function, has been -associated with particulate matter (PM) air pollution, especially in older patients and those with cardio-vascular diseases. However, the effect of PM exposure on cardiac autonomic function in young, healthy adults has received less attention.
  
  
  OBJECTIVE
  We evaluated the relationship between exposure to traffic-related PM with an aerodynamic diameter <or= 2.5 microm (PM2.5) and HRV in a highly exposed panel of taxi drivers.
  
  
  METHODS
  Continuous measurements of personal exposure to PM2.5 and ambulatory electrocardiogram monitoring were conducted on 11 young healthy taxi drivers for a 12-hr work shift during their work time (09002100 hr) before, during, and after the Beijing 2008 Olympic Games. Mixed-effects regression models were used to estimate associations between PM2.5 exposure and percent changes in 5-min HRV indices after combining data from the three time periods and controlling for potentially confounding variables.
  
  
  RESULTS
  Personal exposures of taxi drivers to PM2.5 changed markedly across the three time -periods. The standard deviation of normal-to-normal (SDNN) intervals decreased by 2.2% [95% confidence interval (CI), 3.8% to 0.6%] with an interquartile range (IQR; 69.5 microg/m3) increase in the 30-min PM2.5 moving average, whereas the low-frequency and high-frequency powers decreased by 4.2% (95% CI, 9.0% to 0.8%) and 6.2% (95% CI, 10.7% to 1.5%), respectively, in association with an IQR increase in the 2-hr PM2.5 moving average.
  
  
  CONCLUSIONS
  Marked changes in traffic-related PM2.5 exposure were associated with altered cardiac autonomic function in young healthy adults.
authors.affiliation: Peking University School of Public Health, Beijing, China.
authors.forename: Shaowei
authors.initials: S
authors.lastname: Wu
authors.forename: Furong
authors.initials: F
authors.lastname: Deng
authors.forename: Jie
authors.initials: J
authors.lastname: Niu
authors.forename: Qinsheng
authors.initials: Q
authors.lastname: Huang
authors.forename: Youcheng
authors.initials: Y
authors.lastname: Liu
authors.forename: Xinbiao
authors.initials: X
authors.lastname: Guo
mesh_terms: D000328:Adult; D000397:Air Pollution / Q000009:adverse effects* / Q000517:prevention & control; D000704:Analysis of Variance; D001334:Automobile Driving; D001341:Autonomic Nervous System / Q000187:drug effects / Q000503:physiopathology; D002681:China; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D016273:Occupational Exposure; D052638:Particulate Matter / Q000633:toxicity; D012044:Regression Analysis; D012307:Risk Factors; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D052638:Particulate Matter; D001335:Vehicle Emissions