A Study on the Pervalence and Risk Factors of Liver Dysfunction among the Workers in Chemical Factors

Cheong, Hae Kwan; Kim, Joung Soom

Abstract

The object of this study is to evaluate the possibility of chemical-induced liver disorder among workers exposed to various chemicals and to classify the the liver function abnormalities by causes and to analyse the risk factors for each liver disorders. A cross-sectional study including questionnaire survey, physical examination, laboratory tests and ultrasonography of liver was conducted on 1,126 workers, 459 workers in a coal chemical plant(company A) and 667 workers in an insulation material manufacturing factory(company B). An industrial hygienist reviewed the chemicals used in both companies and evaluated the work environments to classify the workers by chemical exposure semiquantitatively. The results are as follows; 1. Of 459 workers in company A, 83 workers(18.1 %) are classified as nonexposed, 163(35.5%) as short-term exposure group, 155(33.8 %) as intermediately exposed group and 58(12.6 %) as long-term exposed group based on the mean daily exposure to hepatotoxic chemicals evaluated by an industrial hygienist. Of 667 workers in company B, 484(72.6 %) workers were classified as nonexposed and 183(35.5 %) as exposed. 2. Workers with SGOT level higher than 40 IU/l were 46(10.0 %) in company A and 77(11.5 %) in company B, and those with SGPT level higher than 35 IU/l were 118(25.7 %) in company A and 198(29.7 %) in company B. The differences were not significant between companies and between exposure groups(p>0.05). Workers with ?-GT level higher than 62 IU/l were 29(6.3 %) in company A and 77(11.5 %) in company B(p<0.01). The difference between exposure groups was not significant(p>0.05) within companies. Workers with liver function abnormalities(defined as SGOT higher than 40 IU/l or SGPT higher than 35 IU/l, Ministry of Labor, 1989) were 338(30.0 %) among 1,126 workers. Of 338 workers with liver function abnormalities 139(12.3 %) had fatty liver by ultrasonography, 79(7.0 %) had alcoholic liver(defined as workers with liver function abnormalities with weekly alcohol consumption greater than 280 g for more than 5 years), 54(4.8 %) had hepatitis B, 12(1.1 %) had hepatitis C and the other 114(33.7 %) was not otherwise classified. Prevalences of alcoholic liver and fatty liver were significantly lower in company A(prevalence ratio 0.24 for alcoholic liver, p<0.001; prevalence ratio 0.76 for fatty liver, p<0.05) but prevalences of liver disorders between exposure groups within companies were not significant(p>0.05). 3. Summary prevalence ratios(SPR) of liver function abnormalities, fatty liver and other liver disorders, adjusted by age and company were not significantly higher in exposed group in any chemicals(p>0.05) but in some chemicals, SPRs were significantly lower. 4. On simple analysis of risk factors for liver function abnormalities, prevalence odds ratio(POR) of those with age between 30 and 39 was 1.54(p<0.01) and those with age over 40 was 1.51(p<0.01). POR of those with histories of liver disorders and general anesthesia was 1.77(p<0.001) and 4.02 for those with overweight and 6.23 for those with obesity, defined by body mass index(p<0.001). 5. On logistic regression analysis, risk factors of liver function abnormality were fatty liver(POR 2.92 for grade 1, 12.15 for grade 2), presence of hepatitis B surface antigen(POR 3.62) and obesity(POR 5.38 for overweight and 16.52 for obesity). Presence of hepatitis B surface antigen(POR 0.18) was the only preventive factor of fatty liver. Company(POR 0.30) and obesity(POR 2.49 for overweight, 4.52 for obesity) were related to the alcoholic liver. Obesity(POR 2.94 for overweight) was the only significant risk factor of hepatitis B and there was no significant risk factor for liver function abnormality not otherwise classified. It is concluded that the evidence of liver disorder related with chemical exposure is not evident in these factories. It is also postulated that fatty liver and alcoholic liver is most common causes of liver function abnormalities among workers and effort for weight control and improvement of life style should be done.