Attributable risks for hepatocellular carcinoma in northern Italy.

The population attributable risks (ARs) for hepatocellular carcinoma (HCC) were estimated in relation to low education level, heavy alcohol consumption, low vegetable and fruit intake, history of hepatitis, diabetes, liver cirrhosis and oral contraceptive use, using data from a case-control study conducted between 1984 and 1993 in Northern Italy. Cases were 320 patients (235 males and 85 females) with histologically or serologically confirmed HCC, and controls were 1408 patients (1031 males and 377 females) admitted to the same network of hospitals for acute, non-neoplastic or non-digestive tract conditions, unrelated to any of the known or likely risk factors for primary liver cancer. The ARs were 40% for low vegetable and fruit consumption, 31% for low education, 18% for liver cirrhosis, 16% for hepatitis, 8% for diabetes and 7% for heavy alcohol consumption. Together, these factors explained 74% of hepatocellular cancer cases. Compared with females, males had higher ARs for cirrhosis (21% versus 11%), diabetes (10% versus 2%) and heavy alcohol consumption (9% versus 1%). The percentage of HCC attributable to all factors considered together was 78% for males and 67% for females. Thus, even if available information on hepatitis and dietary factors was limited, and the AR estimates were based on several arbitrary assumptions, available knowledge could, in principle, reduce the burden of the disease in Italy from 3300 deaths to approximately 750 for males, and from 1600 to approximately 500 for females.