Association of Polycyclic Aromatic Hydrocarbons exposure with sleep quality among coking plant workers

Abstract

Objective: To explore the relationship between polycyclic aromatic hydrocarbons (PAHs) exposure and sleep quality in workers from a coking plant. Methods: From April to June 2019. Selected 632 employed workers in the coking plant of a large state-owned enterprise in Shanxi Province as the exposed group, and 477 employed workers in the water-pump plant belonged to the same enterprise as the control group. We used self-designed questionnaires to collect the basic information of subjects. We measured the concentrations of 12 PAHs in the peripheral blood of workers using gas chromatography-mass spectrometry (GC-MS) ; Pittsburgh Sleep Quality Index (PSQI) was used to evaluate the sleep quality of workers; The relationship between plasma PAHs concentration and sleep quality was analyzed using multiple linear regression model, restricted cubic spline (RCS) regression and logistic regression. Results: The concentration of 12 polycyclic aromatic hydrocarbons in the peripheral blood of the exposure group was (2.36±1.46) ng/ml, which was significantly higher than that of the control group (2.19±1.21) ng/ml. The detection rate of sleep disorder in the exposure group (18.0%) was higher than that in the control group (16.8%) , which was manifested by the significantly increased scores in subjective sleep quality, sleep latency, sleep disorders, daytime dysfunction, and PSQI. Multiple linear regression analysis showed that the PSQI score of workers in the high exposure group decreased by 0.80 (95% CI: -1.40~-0.19) points compared with the low exposure group, with a statistically significant difference (P<0.05) . RCS analysis showed a non-linear dose-response relationship of PSQI score with PAHs cumulative exposure (plasma PAHs concentration multiplied by length of service) . The results of logistic regression showed that compared with the low level group, the risk of somnipathy in the middle level group of PAHs cumulative exposure decreased by 44%, among which the risk of sleep disorder in the drinkers decreased by 40%, while the risk of somnipathy in the high level group increased by 96% compared with the low level group. Stratified analysis of alcohol drinking habit showed non-significant difference in PSQI score with low, medium, and high levels of PAHs cumulative exposure in non-drinkers (P>0.05) , and that the PSQI score was significantly increased in alcohol drinkers with high level of PAHs cumulative exposure compared to those with low and medium levels of PAHs cumulative exposure. Conclusion: The workers in the coking plant had high levels of PAHs in plasma and poor sleep quality, Higher level of PAHs cumulative exposure (>1396.56ng/ml) is a risk factor of poor sleep quality.