American Journal of Epidemiology Advance Access originally published online on January 19, 2009
American Journal of Epidemiology 2009 169(7):848-856; doi:10.1093/aje/kwn405
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ORIGINAL CONTRIBUTIONS |
Vascular Function, Inflammation, and Variations in Cardiac Autonomic Responses to Particulate Matter Among Welders
Correspondence to Dr. Shona C. Fang, 665 Huntington Avenue, Building 1, Room 1402, Boston, MA 02115 (e-mail: sfang{at}hsph.harvard.edu).
Received for publication May 30, 2008. Accepted for publication December 8, 2008.
Patients with health conditions associated with impaired vascular function and inflammation may be more susceptible to the adverse health effects of fine particulate (particulate matter with a mass median aerodynamic diameter of 
2.5 µm (PM2.5)) exposure. In 2006, the authors conducted a panel study to investigate directly whether vascular function and inflammation (assessed by C-reactive protein) modify PM2.5-associated reductions in heart rate variability among 23 young male workers (mean age, 40 years) from Massachusetts. Concurrent 24-hour ambulatory electrocardiogram and personal PM2.5 exposure information was collected over a total of 36 person-days, including either or both welding and nonwelding days. Linear mixed models were used to examine the 5-minute standard deviation of normal-to-normal intervals (SDNN) in relation to the moving PM2.5 averages in the preceding 1–4 hours. C-reactive protein levels and 3 measures of vascular function (augmentation index, mean arterial pressure, and pulse pressure) were determined at baseline. The authors observed an inverse association between the 1-hour PM2.5 and 5-minute SDNN. Greater SDNN declines were observed among those with C-reactive protein (Pinteraction < 0.001) and augmentation index (P = 0.06) values at or above the 75th percentile and pulse pressure values below the 75th percentile (P < 0.001). Systemic inflammation and poorer vascular function appear to aggravate particle-related declines in heart rate variability among workers.
augmentation; C-reactive protein; disease susceptibility; heart rate; inflammation; particulate matter; vascular diseases; welding
Abbreviations: AIx, augmentation index; CI, confidence interval; PM2.5, particulate matter with a mass median aerodynamic diameter of
2.5 µm; SDNN, standard deviation of normal-to-normal intervals