title: Daily variation of particulate air pollution and poor cardiac autonomic control in the elderly.
abstract: examined the cardiac autonomic response to daily variations in PM in 26 elderly (mean age 81) individuals for 3 consecutive weeks. Several standardized methods were used to measure 24-hr average PM concentrations prior to the clinical test inside (indoor PM2.5) and immediately outside (outdoor PM2.5 and PM2.5-10) of participants' residences. Resting, supine, 6-min R wave to R wave (R-R) interval data were collected to estimate high frequency (0.15-0.40 Hz) and low frequency (0.04-0.15 Hz) powers and standard deviation of normal R-R intervals (SDNN) as cardiac autonomic control indices. Participant-specific lower heart rate variability days were defined as days for which the high-frequency indices fell below the first tertile of the individual's high-frequency distribution over the study period. Indoor PM2.5 > 15 microg/m3 was used to define high pollution days. Results show that the odds ratio (95% confidence interval) of low heart rate variability high frequency for high (vs. not high) pollution days was 3.08 (1.43, 6.59). The ss-coefficients (standard error) from mixed models to assess the quantitative relationship between variations in indoor PM2.5 and the log-transformed high frequency, low frequency, and SDNN were: -0.029 (0.010), -0.027 (0.009), and -0.004 (0.003), respectively. This first study of cardiac autonomic control response to daily variations of PM2.5 indicates that increased levels of PM2.5 are associated with lower cardiac autonomic control, suggesting a possible mechanistic link between PM and cardiovascular disease mortality.
authors.affiliation: Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: D
authors.initials: D
authors.lastname: Liao
authors.forename: J
authors.initials: J
authors.lastname: Creason
authors.forename: C
authors.initials: C
authors.lastname: Shy
authors.forename: R
authors.initials: R
authors.lastname: Williams
authors.forename: R
authors.initials: R
authors.lastname: Watts
authors.forename: R
authors.initials: R
authors.lastname: Zweidinger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000397:Air Pollution; D001341:Autonomic Nervous System / Q000502:physiology*; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000294:innervation*; D006339:Heart Rate; D006801:Humans; D008297:Male