URINARY AFLATOXIN LEVELS, HEPATITIS-B VIRUS-INFECTION AND HEPATOCELLULAR-CARCINOMA IN TAIWAN

Using a urinary immunoassay to measure aflatoxin metabolites, we exami ned the associations between exposure to aflatoxin, chronic infection with the hepatitis-B virus (HBV) and background rates of hepatocellula r carcinoma (HCC) mortality in a cross-sectional survey of 250 residen ts from 8 areas of Taiwan with a 4-fold variation in age-adjusted HCC mortality. Specimens of fasting blood and overnight urines were used t o determine HBV carrier status and excretion of aflatoxin in the subje cts surveyed. While the prevalence of hepatitis-B virus carriers showe d moderate variability, there was a 500-fold range in urinary aflatoxi n levels. Mean log-transformed levels of aflatoxin metabolites were si milar in males and females and in HBV carriers and non-carriers. In th e 8 townships, HCC mortality correlated positively with both area HBV carrier prevalence and mean aflatoxin levels. The primary analyses, ho wever, were conducted at the individual level. Each subject's aflatoxi n level was treated as the response variable in a multiple regression model, and the corresponding sex-specific area HCC rate was included a s a predictor along with the individual's carrier status, age and sex; alcohol consumption and cigarette smoking were also considered. In th ese analyses, a significant association was again observed between the marker of aflatoxin exposure and the background rate of HCC mortality . In females, the slope of the regression line was somewhat steeper in HBV carriers, but this pattern was not seen in males and formal testi ng yielded no statistically significant evidence of an interaction. Ou r findings are consistent with the hypothesis that aflatoxin plays an independent role in hepatocellular carcinoma in Taiwan. (C) 1993 Wiley -Liss, Inc.