VIRAL-INFECTIONS AND CHEMICAL EXPOSURES AS RISK-FACTORS FOR HEPATOCELLULAR-CARCINOMA IN VIETNAM

A case-control study investigating risk factors for hepatocellular car cinoma (HCC) was conducted in Hanoi, in the north of Vietnam, between 1989 and 1992. Male cases of HCC (152) diagnosed in 2 hospitals were i ncluded. Hospital controls (241) admitted mainly to abdominal surgery departments were frequency-matched to cases for sex, age, hospital and place of residence (Hanoi, province). Odds ratios adjusted for matchi ng variables and other potential confounders were estimated using unco nditional logistic regression, or exact non-parametric statistical inf erence when numbers were small. Positivity for hepatitis B surface ant igen (HBsAg) was the main risk factor for HCC in this sample. Five sub jects (3 cases, 2 controls) had been infected by hepatitis C virus (HC V), and none of them were carriers of HBsAg, giving an OR of 38 associ ated with HCV infection among HBsAg-negative subjects. Alcohol drinkin g was associated with HCC and interacted with HBsAg positivity. Agricu ltural use of organophosphorous pesticides (30 liters/year or more) an d military service in the south of Vietnam for 10 years or more were a lso associated with an increased risk of HCC. This study confirms the major role played by HBV infection and its association with HCC in sou th-east Asia. It also suggests how other factors such as alcohol consu mption or exposure to chemicals may interact with HBV infection. (C) 1 993 Wiley-Liss, Inc.