A case-control study of hepatocellular carcinoma in Mongolia

Abstract

Introduction: Mongolia has the highest reported incidence of hepatocellular carcinoma (HCC) and the highest prevalence of viral hepatitis, both hepatitis B virus (HBV) and hepatitis C virus (HCV), in the world. Aim: To investigate risk factors of HCC in Mongolia. Material and method: Between 2016 and 2018, we prospectively enrolled 249 newly diagnosed HCC cases at the Mongolia National Cancer Center and 248 healthy controls from the community. Information on demographic characteristics, smoking and drinking, diet, and medical history and family history of cancer was obtained through face to face in-depth interview while viral hepatitis B, C, and D status was assessed in collected blood samples in both cases and controls. We used multivariable logistic regression analyses to assess independent associations with HCC, adjusting for multiple confounding variables. Results: About 93.3% of the cases had HBV or HCV infection and 41% of the controls had viral hepatitis infection. Among the cases, 61.3% had HCV infection and of these, 39% also had HBV co-infection. About 56% of the cases had HBV infection and 81% of the HBV+ patients also had HDV co-infection. Compared to controls without HBV and HCV infection, HBV/HDV co-infection were associated with the highest risk for HCC (OR=217.95, 95% CI 68.1-880.3, P<0.001), followed by HBV/HCV/HDV co-infection (OR=56.1, 95% CI 18.8-201.4, P<0.001), then HBV and HCV mono-infection (adjusted OR=15.5 and 6.4, respectively). In addition, current smoking was associated with a 4.4-fold risk (OR=4.4, 95% CI 1.90-10.6, P<0.001) and vegetable consumption was associated with a reduced risk, with having 11-20 serving per weeks associated with a 65% reduction in risk (OR=0.35, 95% CI 0.12-0.99, P<0.001). Conclusion: Viral hepatitis, smoking, lower education, lower consumption of vegetables, and family history of liver cancer were strong and significant risk factors for HCC.