Interaction of vinyl chloride monomer exposure and hepatitis B viral infection on liver cancer.

Vinyl-chloride monomer (VCM), a human carcinogen, has caused angiosarcoma of the liver. Recent studies have shown that VCM exposure is associated with hepatocellular cancer. In Taiwanese studies, the majority of VCM-exposed workers with liver cancer had history of hepatitis B virus (HBV) infection. To determine the role of HBV on the development of liver cancer in the VCM-exposed workers, we conducted a case-control study from a previously established polyvinyl chloride (PVC) cohort consisting of 4096 male workers from six PVC polymerization plants. A total of 18 patients with liver cancer, and 68 control subjects matched for age and specific plant of employment were selected. Detailed history of the participants that included alcohol consumption status, cigarette use, occupation, and family history of chronic liver disease were obtained using an interviewer-administered questionnaire. When the HBV surface antigen (HBsAg)-negative subjects without history of tank-cleaning were used as the reference, the HBsAg-negative subjects with history of tank-cleaning demonstrated a 4.0-fold greater risk of liver cancer (95% confidence interval: 95% CI = 0.2-69.1). The HBsAg carriers without history of tank-cleaning revealed a 25.7-fold greater risk of liver cancer (95% CI = 2.9-229.4). Whereas the HBsAg carriers with history of tank-cleaning revealed the greatest risk (matched odds ratio (ORm) 396.0, 95% CI = 22.6 -infinity) of developing liver cancer among subjects with different VCM-exposure status and HBsAg status categories. Further analysis showed the interaction term was significant (P < .01). Therefore, our results suggest an interaction between occupational VCM exposure and HBV infection for the development of liver cancer.