Association of Urinary Phenol Concentration and Blood Biochemical Indices in Coke Oven Workers

Abstract

Objective: To explore the association of urinary phenol concentration and blood biochemical indices in coke oven workers. Methods: From April to may 2019, we investigated 771 employing coke oven workers from a coke plant in Taiyuan city, and categorized into benzene-exposed group (n=402) and control group (n=369) based on their benzene exposures in workplace and urophenol concentrations. All subjects were interviewed face-to-face using a questionnaire including name, age (year) , gender, smoking and drinking habits, personal vocational history, working length (year) , and occupational protection, etc. Post-shift urine samples detected using a gas chromatography-hydrogen flame ionization detector. Fasting venous blood was drawn in the morning and centrifuged, the separated serum were detected the following items using an automatic blood biochemistry analyzer. Covariance and multiple linear regression were used to test the association of urinary phenol concentration and the levels of all the blood biochemical indices. Results: The subjects were predominantly males (n=719, 93.3%) , with an average age of (42.3±8.2) years and an average working length of (20.6±8.2) years. Compared with the control group, the benzene-exposed group were significantly different in age, working length of years, gender, smoking and drinking habits (P<0.05) . The median (interquartile interval) concentration of urinary phenol was 6.00 (0.00-33.00) μg/ml in the benzene-exposed group, which was significantly higher than that in the control group (P<0.05) . Covariance analysis indicated that the fasting blood glucose, total cholesterol and high density cholesterol in the benzene-exposed group were significantly reduced compared with the control group, yet the serum creatinine, serum uric acid and triglyceride were significantly increased (P<0.05) . Multiple linear regression showed that, an increase of each natural logarithm (Ln) transformed urinary phenol concentration was significantly associated with increases in serum uric acid level [9.82 (95%CI: 2.18-17.47) μmol/L] and cholesterol level[0.10 (95%CI:0.00-0.20) mmol/L]. An increase of each Ln-transformed accumulated benzene exposure levels was significantly associated with an increase in total cholesterol level[0.09 (95%CI: 0.01-0.17) mmol/L]. Conclusion: Occupational benzene exposure is possibly related to the variation of purine and total cholesterol metabolism in coke oven workers.