Hepatitis B Surface Antigen, Hepatitis C Virus Antibody, Body Mass Index, and Alcohol Drinking among Workers with Elevated Serum Alanine Aminotransferase

Method. We conducted a case-control study on liver diseases among Japanese workers to examine associations between elevated serum alanine aminotransferase (alanine aminotransferase value ≥ 50 IU/liter) and selected factors such as hepatitis B surface antigen positive, hepatitis C virus antibody positive, body mass index, and alcohol drinking. Out of 3,738 workers (1,477 males and 2,261 females) in a supermarket chain, 91 workers with an elevated serum alanine aminotransferase value (≥ 50 IU/liter) were classified as cases and 182 workers with normal serum alanine aminotransferase value and without an episode of blood transfusion were randomly selected as controls. Results. Prevalence rates of hepatitis B surface antigen positive and hepatitis C virus antibody positive were 4.4 and 23.1% among the overall cases, 2.9 and 11.8% among the cases with 100 > alanine aminotransferase value ≥ 50, and 8.7 and 56.5% among the cases with alanine aminotransferase value ≥ 100. A logistic regression analysis was conducted. Odds ratios were 4.94 for hepatitis B surface antigen positive (P < 0.05) and 77.19 for hepatitis C virus antibody positive (P < 0.001). Odds ratios for body mass index increased with increasing body mass index values; 3.32 for 26 > body mass index ≥ 24 (P < 0.01) and 5.03 for body mass index ≥ 26 (P < 0.001). No increased risk was observed among regular drinkers of less than 27 g/day of ethanol (odds ratio is 0.23) or of 27-53 g/day of ethanol (odds ratio is 0.47). A slightly increased odds ratio of 1.35 was observed among regular drinkers of 54-81 g/day of ethanol, but this was not statistically significant. Conclusions. Our results suggest that hepatitis C virus and high body mass index are predominant factors in elevated serum alanine aminotransferase levels among Japanese workers, while alcohol drinking is a minor factor.