Coarse Particles and Heart Rate Variability among Older Adults with Coronary Artery Disease in the Coachella Valley, California

• Published in: Environmental health perspectives 2006-08, Vol.114 (8), p.1215-1220
• Main Authors: Lipsett, Michael J., Tsai, Feng C., Roger, Linda, Woo, Mary, Ostro, Bart D.
• Format: Article
• Language: English
• Subjects: Aged; Air pollutants; Air pollution; Air Pollution - adverse effects; Atrial fibrillation; California - epidemiology; Coronary artery disease; Coronary Artery Disease - epidemiology; Coronary Artery Disease - physiopathology; Coronary heart disease; Data Collection; Data Interpretation, Statistical; Electrocardiography; Environmental health; Environmental Monitoring; Epidemiological Monitoring; Female; Health aspects; Heart rate; Heart Rate - physiology; Humans; Male; Middle Aged; Mortality; Older adults; Ozone; Particle Size; Particulate matter; Pollution monitoring; Respiratory Function Tests
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.8856

Alterations in cardiac autonomic control, assessed by changes in heart rate variability (HRV), provide one plausible mechanistic explanation for consistent associations between exposure to airborne pariculate matter (PM) and increased risks of cardiovascular mortality. Decreased HRV has been linked with exposures to PM10 (PM with aerodynamic diameter $\leq 10 \mu m$) and with fine particles (PM with aerodynamic diameter $\leq 2.5 \mu m$) originating primarily from combustion sources. However, little is known about the relationship between HRV and coarse particles [PM with aerodynamic diameter $10-2.5 \mu m$ ($PM_{10-2.5}$)], which typically result from entrainment of dust and soil or from mechanical abrasive processes in industry and transportation. We measured several HRV variables in 19 nonsmoking older adults with coronary artery disease residing in the Coachella Valley, California, a desert resort and retirement area in which ambient PM10 consists predominantly of $PM_{10-2.5}$. Study subjects wore Holter monitors for 24 hr once per week for up to 12 weeks during spring 2000. Pollutant concentrations were assessed at nearby fixed-site monitors. We used mixed models that controlled for individual-specific effects to examine relationships between air pollutants and several HRV metrics. Decrements in several measures of HRV were consistently associated with both PM10 and $PM_{10-2.5}$; however, there was little relationship of HRV variables with PM2.5 concentrations. The magnitude of the associations (~ 1-4% decrease in HRV per $10-\mu g/m^3$ increase in PM10 or $PM_{10-2.5}$) was comparable with those observed in several other studies of PM. Elevated levels of ambient $PM_{10-2.5}$ may adversely affect HRV in older subjects with coronary artery disease.