Effect of vinyl chloride on liver function and serum sex hormones in male workers / 中国职业医学

OBJECTIVE: To explore the effect of vinyl chloride on the blood sex hormones and liver function of male workers. METHODS: A total of 129 male vinyl chloride workers(exposure group) and 128 male office workers who were not exposed to occupational hazards(control group) were selected as study subjects by judgment sampling method. The time weighted average concentration(C_(TWA)) of vinyl chloride in the workplace air was measured. The level of urine thiodiglycolic acid(TDGA), blood routine, electrocardiogram and liver B-ultrasound were performed on the subjects. The serum levels of liver function and sex hormones were measured. RESULTS: The median of C_(TWA) of vinyl chloride in the workplace was 0.90 mg/m~3, and the geometric mean was 1.40 mg/m~3. The level of urine TDGA in the exposed group was higher than that of the control group(median: 0.68 vs 0.02 mg/g Cr, P<0.01). The abnormal rate of hemoglobin level, erythrocyte count, leukocyte count, hematocrit, mean platelet volume, aspartate transaminase, total bilirubin, indirect bilirubin and liver B-ultrasound increased in the exposure group than that of the control group(P<0.05). The levels of serum prolactin, leuteinizing hormone(LH), follicle-stimulating hormone and estradiol in the exposure group increased, the abnormal rates of prolactin, LH and estradiol increased, and the level of testosterone decreased compared with the control group(P<0.05). The levels of prolactin in the low-, medium-and high-TDGA subgroups in the exposure group increased(P<0.05), and the abnormal rates increased compared with the control group(P<0.017). CONCLUSION: Vinyl chloride can cause liver function damage in male workers and have reproductive toxicity. Prolactin can be used as a biomarker of reproductive toxicity of vinyl chloride.

Urinary Excretion of Thiodiglycolic Acid According to Sampling Time in Workers Exposed to Vinyl Chloride Monomer / 대한산업의학회지

OBJECTIVES: The study was performed to investigate the changes of urinary thiodiglycolic acid (TDGA) concentration in workers exposed to vinyl chloride monomer (VCM) according to the time of sampling urine. METHODS: The personal exposure to airborne VCM was assessed and urinary TDGA concentration was sampled in 31 workers employed in a VCM and polyvinyl chloride (PVC) manufacturing factory. Urinary TDGA was sampled three times: before the start of the shift after 3 days off (TDGA1), after the end of the first-day shift (TDGA2) and before starting the following day shift after completing the oneday shift (TDGA3). Urinary TDGA in 30 workers who had not been exposed to airborne VCM was sampled after the end of the shift. A gas chromatography/pulsed flame photometric detector (GC/PFPD) was utilized to analyze TDGA concentration in urine after the urine was methylated with trimethylsilyldiazomethane(2.0M in diethyl ether). RESULTS: The creatinine level was 0.179+/-0.271 mg/g in the control workers and 0.218+/-0.443 mg/g in the workers before the start of the shift after 3 days off (TDGA1), showing no significant difference (p=0.7035). Urine samples were compared according to sampling time in order to investigate the change of urinary TDGA concentration in the case of continuous exposure to airborne VCM. In VCM-exposed workers, urinary creatinine concentration was 0.434+/-0.623 mg/g in TDGA2 and 0.767+/-1.056 mg/g in TDGA3, which indicated a gradual but significant increase (p=0.024). In terms of the statistical correlation between airborne VCM and urinary TDGA to evaluate exposure dose per day, of the three urinary TDGA concentrations, TDGA3 showed the highest degree of regression (R(2)=0.4215) with 8h-TWA airborne VCM concentration. CONCLUSION: Based on this result, the excretion half-life of urinary TDGA was assumed to be less than 3 days, because the concentration of urinary TDGA at 3 days after exposure to airborne VCM was decreased to the level of urinary TDGA concentration in the control workers. The concentration of urinary TDGA increased in the case of continuous shift, due to the accumulation of residual metabolites of TDGA. It was considered that TDGA3 can be applied as a useful biological index to evaluate the exposure dose of airborne VCM during one day because TDGA3 showed the highest correlation with the exposure dose of airborne VCM in the previous shift day.

The variation of thiodiglycolic acid concentration in urine with vinyl chloride exposure levels in rats / 대한산업의학회지

OBJECTIVES: It is the objective of this research to identify the variation of thiodiglycolic acid (TdGA) in urine with vinyl chloride monomer (VCM) exposure levels through methylation. METHODS: After rats were exposed to vinyl chloride monomer of 4 levels, 0 mg/m3, 50 mg /m3, 150 mg/m3, 500 mg/m3, respectively, of which urine was sampled in each sampling time of 0 hour, 2 hours, 4 hours, 8 hours, 16 hours, 24 hours, 36 hours, 48 hours. After urine had been methylated with diazomethane in the preliminary experiment and the peak of 146 m/z had been verified, the main experiment was done. RESULTS: In the variation of TdGA with sampling times, concentration of TdGA increased rapidly in 4 hours and then decreased after 8 hours. When the variation of urinary .TdGA concentration in urine according to exposure level of VCM was verified through Kruskal-Wallis statistical method at each sampling time, the significant increment with the exposure levels at 2 hours, 4 hours, 8 hours after exposure was clarified. CONCLUSION: TdGA concentration in urine with increment of VCM exposure level increased, especially significantly at 2 hours, 4 hours, 8 hours of sampling time.