Objectives: Exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with cardiopulmonary mortality and cardiovascular events. This study investigated the association between a biological marker of PAH exposure, assessed by urinary 1-hydroxypyrene (1-OHP), and heart-rate variability in an occupational cohort of boilermakers.
Methods: Continuous 24 h monitoring of the ambulatory electrocardiogram (ECG) and pre- and postshift urinary 1-OHP were repeated over extended periods of the work week. Mixed-effects models were fitted for the 5 min SD of normal-to-normal intervals (SDNN) in relation to urinary 1-OHP levels pre- and postworkshift on the day they wore the monitor, controlling for potential confounders.
Results: The authors found a significant decrease in 5 min SDNN during work of -13.6% (95% CI -17.2% to -9.8%) per SD (0.53 μg/g creatinine) increase in the next-morning preshift 1-OHP levels. The magnitude of reduction in 5 min SDNN was largest during the late night period after work and increased with each SD (0.46 μg/g creatinine) increase in postshift 1-OHP levels.
Conclusion: This is the first report providing evidence that occupational exposure to PAHs is associated with altered cardiac autonomic function. Acute exposure to PAHs may be an important predictor of cardiovascular disease risk in the work environment.