Traffic related pollution and heart rate variability in a panel of elderly subjects

• Published in: Thorax Vol. 60; no. 6; pp. 455 - 461
• Main Authors: Schwartz, J, Litonjua, A, Suh, H, Verrier, M, Zanobetti, A, Syring, M, Nearing, B, Verrier, R, Stone, P, MacCallum, G, Speizer, F E, Gold, D R
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Thoracic Society 01.06.2005; BMJ; BMJ Publishing Group LTD; BMJ Group
• Subjects: Aged; Aged, 80 and over; Air pollution; Arrhythmias, Cardiac - chemically induced; Biological and medical sciences; Carbon - adverse effects; Carbon - analysis; Carbon monoxide; Carbon Monoxide - analysis; Carbon Monoxide - toxicity; elderly; Electrocardiography, Ambulatory; Environmental Exposure; Female; Heart rate; heart rate variability; HRV; Humans; Male; Medical sciences; Middle Aged; myocardial infarction; Nitrogen dioxide; Nitrogen Dioxide - analysis; Nitrogen Dioxide - toxicity; NO2; Outdoor air quality; Ozone - analysis; Ozone - toxicity; particulate matter; Pneumology; Public health; Questionnaires; SO2; Sulfur Dioxide - analysis; Sulfur Dioxide - toxicity; sulphur dioxide; Summer; traffic; Vehicle Emissions - analysis; Vehicle Emissions - toxicity; United States > US; Human; Heart rate; Pollution; Respiratory disease; Variability; Cardiovascular disease; Elderly
• ISSN: 0040-6376; 1468-3296
• DOI: 10.1136/thx.2004.024836

Background: Particulate air pollution has been associated with increased cardiovascular deaths and hospital admissions. To help understand the mechanisms, the types of particles most involved, and the types of persons most susceptible, the association between exposure to summertime air pollution and heart rate variability (HRV) was examined in a panel study of 28 elderly subjects. Methods: Subjects were seen once a week for up to 12 weeks and HRV (SDNN, r-MSSD, PNN50, low frequency/high frequency ratio (LFHFR)) was measured for approximately 30 minutes at each session using a defined protocol. Temperature, day of the week, and hour of the day were controlled, and dummy variables for each subject were controlled for subject specific risk factors. Results: PM2.5 was associated with r-MSSD (−10.1% change for an interquartile range (IQR) increase in exposure (95% CI −2.8 to −16.9)) and PNN50, but stronger associations were seen with black carbon, an indicator of traffic particles, which was also associated with SDNN (−4.6% per IQR (95% CI −2.0 to −7.2)) and LFHFR. Secondary particles were more weakly associated with r-MSSD, as was ozone. No associations were seen with SO2 or NO2. CO had similar patterns of association to black carbon, which disappeared after controlling for black carbon. Black carbon had a substantially higher effect on SDNN in subjects who had had a previous myocardial infarction (−12.7%, 95% CI −5.7 to −19.25). Conclusions: Particles, especially from traffic, are associated with disturbances of autonomic control of the heart.