Cardiac autonomic dysfunction from occupational exposure to polycyclic aromatic hydrocarbons

Abstract

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.

Figure 1

Percent change and 95% CIs in 6-hour time window in 5-min SDNN and 5-min HR associated per 1 SD (0.53 μg/g creatinine) change in preshift 1-OHP levels and 1 SD (0.46 μg/g creatinine) change in postshift 1-OHP levels using mixed-effects models adjusting for age, cotinine, working time or not (y/n), and day of week. SDNNs were additionally adjusted for HR. Error bars indicate 95% confidence intervals. Work time and night time indicate the periods during the day before preshift urine sampling. The star symbol-marked worktime represents the working daytime hours on the day of monitoring when postshift urines were sampled. The night time with the star symbol denotes the period after postshift urine sampling.