Background/aims: The liver function tests (LFTs), such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyltranspeptidase (gamma-GT), have been widely used as screening tests but their low positive predictive value can cause many false positive results. To evaluate the clinical usefulness of these tests, we analyzed the serial LFT results for factory workers, and we compared the risk factors for the groups that were divided according to the serial LFT results.
Methods: From June 2001 to October 2001, 1223 consecutive healthy workers in a single factory were enrolled in our study; a questionnaire, LFT and liver ultrasonography were done for all the subjects. The previous LFT results were collected from the Annual health examination survey. According to the abnormalities on the serial LFT, the participants were classified into three groups (abnormal-in-both, alternating or, normal-in-both) and the risk factors were compared among these groups using multiple logistic regression analysis.
Results: The prevalence of LFT abnormality on a single test was 16.8%, but on the serial LFT, only 5% of the study participants showed consistent abnormality. The risk factors for the abnormal-in-both group, compared with the alternating group, were liver ultrasonography abnormality such as a fatty liver (odds ratio, 2.2; P=0.026) and a heavy alcohol intake (more than 210 g/week) (odds ratio, 7.2; P=0.064). HBsAg was not a significant risk factor for any of the three groups.
Conclusions: In factory workers having serial LFT abnormalities, alcoholic liver disease could be the principal cause of abnormal LFT. Even if the HBsAg were positive in patients with abnormal LFT, there is the possibility of another causes for LFT abnormalities such as alcoholic liver disease and non-alcoholic steatosis or steatohepatitis.