The Relationship between Ambient Air Pollution and Heart Rate Variability Differs for Individuals with Heart and Pulmonary Disease Amanda Wheeler,1 Antonella Zanobetti,2 Diane R. Gold,3 Joel Schwartz,2 Peter Stone,4 and Helen H. Suh2 1Health Canada, Ottawa, Ontario, Canada; 2Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA; 3Channing Laboratory, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts, USA; 4Brigham and Women's Hospital, Boston, Massachusetts, USA Abstract Associations between concentrations of ambient fine particles [particulate matter < 2.5 µm aerodynamic diameter (PM2.5) ] and heart rate variability (HRV) have differed by study population. We examined the effects of ambient pollution on HRV for 18 individuals with chronic obstructive pulmonary disease (COPD) and 12 individuals with recent myocardial infarction (MI) living in Atlanta, Georgia. HRV, baseline pulmonary function, and medication data were collected for each participant on 7 days in fall 1999 and/or spring 2000. Hourly ambient pollution concentrations were obtained from monitoring sites in Atlanta. The association between ambient pollution and HRV was examined using linear mixed-effect models. Ambient pollution had opposing effects on HRV in our COPD and MI participants, resulting in no significant effect of ambient pollution on HRV in the entire population for 1-, 4-, or 24-hr moving averages. For individuals with COPD, interquartile range (IQR) increases in 4-hr ambient PM2.5 (11.65 µg/m3) and nitrogen dioxide (11.97 ppb) were associated with 8.3% [95% confidence interval (CI) , 1.7-15.3%] and 7.7% (95% CI, 0.1-15.9%) increase in the SD of normal R-R intervals (SDNN) , respectively. For individuals with MI, IQR increases in 4-hr PM2.5 (8.54 µg/m3) and NO2 (9.25 ppb) were associated with a nonsignificant 2.9% (95% CI, -7.8 to 2.3) and significant 12.1 (95% CI, -19.5 to -4.0) decrease in SDNN. Beta-blocker and bronchodilator intake and baseline forced expiratory volume in 1 sec modified the PM-SDNN association significantly, with effects consistent with those by disease group. Results indicate heterogeneity in the autonomic response to air pollution due to differences in baseline health, with significant associations for ambient NO2 suggesting an important role for traffic-related pollution. Key words: ambient pollution, chronic obstructive pulmonary disease, fine particulate matter, heart rate variability, myocardial infarctions, nitrogen dioxide. Environ Health Perspect 114: 560-566 (2006) . doi:10.1289/ehp.8337 available via http://dx.doi.org/ [Online 15 November 2005] Address correspondence to H.H. Suh, Department of Environmental Health, 401 Park Dr., Landmark West 404G, P.O. Box 15677, Boston, MA 02215 USA. Telephone: (617) 384-8805. Fax: (617) 384-8859. E-mail: hsuh@hsph.harvard.edu We thank E. Edgerton for help with the ambient monitoring data ; F. Speizer, P. Koutrakis, and B. Ryan for their scientific input ; and M. Davey, the field staff, and the study participants for assistance. This work was funded by the National Institute of Environmental Health Sciences (grants ES09825 and ES00002) , the U.S. Environmental Protection Agency (grant R827353) , the Electric Power Research Institute (grant WO7356-01) , and the American Petroleum Institute. The authors declare they have no competing financial interests. Received 23 May 2005 ; accepted 15 November 2005. Correction The affiliation for D.R.G. was incorrect in the manuscript published online. It has been corrected here. The full version of this article is available for free in HTML or PDF formats. |