LACK OF INTERACTION BETWEEN HEPATITIS-C VIRUS AND ALCOHOL IN THE PATHOGENESIS OF CIRRHOSIS - A STATISTICAL STUDY

Background/Aims: In several studies markers of hepatitis C virus infec tion have been shown to be present in alcoholic patients with cirrhosi s. Our work was designed to test the likely hypothesis that this assoc iation is due to an interaction between hepatitis C virus and alcohol in the pathogenesis of cirrhosis. Methods: We compared alcohol consump tion and repartition of anti-HCV antibodies detected by an immunoblot recombinant assay in 101 male patients with cirrhosis and in 120 male controls. Interactions between anti-hepatitis C virus, alcohol and cir rhosis were calculated using log linear hierarchical models for freque ncy data. The basis of the method is that an interaction between hepat itis C virus and alcohol implies that a model built on the hypothesis of a role of hepatitis C virus and alcohol in the disease should be im proved by a coefficient associated with multiplicative effects of hepa titis C virus and alcohol. Results: In patients with cirrhosis the mea n alcohol consumption (148+/-100 g per day) and the incidence of posit ivity for anti-HCV antibodies (45%) were significantly higher than in controls, The results were consistent with a theoretical model built w ith the hypothesis of an independent role of both alcohol and hepatiti s C virus. The goodness of fit between this model and the actual distr ibution of alcohol consumption and hepatitis C virus markers was not i mproved by introduction of an interaction between hepatitis C virus an d alcohol. Conclusions: In alcoholic subjects with hepatitis C virus i nfection, the probability to have cirrhosis seemed to be explained by additive effects of alcohol and hepatitis C virus. From a purely stati stical point of view, no interaction between hepatitis C virus and alc ohol consumption on a multiplicative scale could be demonstrated.