Details

Autor(en) / Beteiligte

• Chen, Jiu-Chiuan
• Jennifer M. Cavallari
• Stone, Peter H.
• Christiani, David C.

Titel

Obesity Is a Modifier of Autonomic Cardiac Responses to Fine Metal Particulates

Ist Teil von

• Environmental health perspectives, 2007-07, Vol.115 (7), p.1002-1006

Ort / Verlag

United States: National Institute of Environmental Health Sciences. National Institutes of Health. Department of Health, Education and Welfare

Erscheinungsjahr

2007

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Background: Increasing evidence suggests that obesity may impart greater susceptibility to adverse effects of air pollution. Particulate matter, especially PM2.5(particulate matter with aerodynamic diameter$\leq 2.5 \mu m$), is associated with increased cardiac events and reduction of heart rate variability (HRV). Objectives: Our goal was to investigate whether particle-mediated autonomic modulation is aggravated in obese individuals. Methods: We examined$PM_{2.5}-mediated$acute effects on HRV and heart rate (HR) using 10 24-hr and 13 48-hr ambulatory electrocardiogram recordings collected from 18 boilermakers ($39.5 \pm 9.1$years of age) exposed to high levels of metal particulates. Average HR and 5-min HRV [SDNN: standard deviation of normal-to-normal intervals (NN); rMSSD: square-root of mean squared-differences of successive NN intervals; HF: high-frequency power 0.15-0.4 Hz] and personal PM2.5exposures were continuously monitored. Subjects with body mass index$\geq 30 kg/m^2$were classified as obese. Mixed-effect models were used for statistical analyses. Results: Half (50%) of the study subjects were obese. After adjustment for confounders, each$1-mg/m^3$increase in 4-hr moving average PM2.5was associated with HR increase of 5.9 bpm [95% confidence interval (CI), 4.2 to 7.7] and with 5-min HRV reduction by 6.5% (95% CI, 1.9 to 11.3%) for SDNN, 1.7% (95% CI, -4.9 to 8.4%) for rMSSD, and 8.8% (95% CI, -3.8 to 21.3%) for HF. Obese individuals had greater$PM_{2.5}-mediated$HRV reductions (2- to 3-fold differences) than nonobese individuals, and had more$PM_{2.5}-mediated$HR increases (9-bpm vs. 4-bpm increase in HR for each$1-mg/m^3$increase in PM2.5; p < 0.001). Conclusions: Our study revealed greater autonomic cardiac responses to metal particulates in obese workers, supporting the hypothesis that obesity may impart greater susceptibility to acute cardiovascular effects of fine particles.