title: Personal exposure to submicrometer particles and heart rate variability in human subjects.
abstract: We conducted a study on two panels of human subjects--9 young adults and 10 elderly patients with lung function impairments--to evaluate whether submicrometer particulate air pollution was associated with heart rate variability (HRV). We measured these subjects' electrocardiography and personal exposure to number concentrations of submicrometer particles with a size range of 0.02-1 microm (NC0.02-1) continuously during daytime periods. We used linear mixed-effects models to estimate the relationship between NC0.02-1 and log10-transformed HRV, including standard deviation of all normal-to-normal intervals (SDNN), square root of the mean of the sum of the squares of differences between adjacent NN intervals (r-MSSD), low frequency (LF, 0.04-0.15 Hz), and high frequency (HF, 0.15-0.40 Hz), adjusted for age, sex, body mass index, tobacco exposure, and temperature. For the young panel, a 10,000-particle/cm3) increase in NC0.02-1 with 1-4 hr moving average exposure was associated with 0.68-1.35% decreases in SDNN, 1.85-2.58% decreases in r-MSSD, 1.32-1.61% decreases in LF, and 1.57-2.60% decreases in HF. For the elderly panel, a 10,000-particle/cm3 increase in NC0.02-1 with 1-3 hr moving average exposure was associated with 1.72-3.00% decreases in SDNN, 2.72-4.65% decreases in r-MSSD, 3.34-5.04% decreases in LF, and 3.61-5.61% decreases in HF. In conclusion, exposure to NC0.02-1 was associated with decreases in both time-domain and frequency-domain HRV indices in human subjects.
authors.affiliation: Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan. ccchan@ha.mc.ntu.edu.tw
authors.forename: Chang-Chuan
authors.initials: CC
authors.lastname: Chan
authors.forename: Kai-Jen
authors.initials: KJ
authors.lastname: Chuang
authors.forename: Guang-Ming
authors.initials: GM
authors.lastname: Shiao
authors.forename: Lian-Yu
authors.initials: LY
authors.lastname: Lin
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000393:Air Pollutants / Q000009:adverse effects*; D001341:Autonomic Nervous System / Q000502:physiology; D004781:Environmental Exposure; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010316:Particle Size
chemical_list: D000393:Air Pollutants