Attributable risk for symptomatic liver cirrhosis in Italy. Collaborative Groups for the Study of Liver Diseases in Italy

BACKGROUNDS/AIMS: Knowledge of the proportion of liver cirrhosis attributable to the main risk factors is largely based on methodologically questionable clinical reports. METHODS: The proportion of newly diagnosed cases of symptomatic liver cirrhosis attributable to known risk factors was estimated by a case-control study performed during 1989-1996 in 23 medical divisions of several hospitals distributed throughout Italy. Cases were 462 inpatients with cirrhosis admitted for the first time for liver decompensation. Controls were 651 patients admitted during the same period and to the same hospitals as the cases, for acute diseases unrelated to alcohol and virus infection. The proportion of symptomatic liver cirrhosis cases due to alcohol intake and hepatitis B and C viruses and the combination of these was expressed as the population attributable risk. RESULTS: Attributable risks were 67.9% (95% confidence interval (CI): 53.8-79.4) for alcohol, 40.1% (95% CI: 35.3-45.2) for hepatitis C virus and 4.4% (95% CI: 2.5-7.6) for hepatitis B virus. The three factors together explained 98.1% (95% CI: 81.6-99.6) of cases in men and 67.0% (95% CI: 50.4-85.8) in women. CONCLUSIONS: Alcohol is the risk factor with the highest impact on symptomatic liver cirrhosis risk in Italy. From a public health viewpoint, with the elimination of the well-known risk factors (particularly alcohol and hepatitis C virus), liver cirrhosis should become a rare disease.