URINARY-EXCRETION OF 2-AMINO-3,8-DIMETHYLIMIDAZO-[4,5-F]QUINOXALINE IN WHITE, BLACK, AND ASIAN MEN IN LOS-ANGELES-COUNTY

The heterocyclic aromatic amines produced by high temperature cooking of foods containing creatin(in)e and amino acids (such as beef, pork, poultry and fish) are a class of potent animal carcinogens and have be en implicated indirectly in human colon and pancreas carcinogenesis. W e studied the urinary excretion of a mutagenic heterocyclic aromatic a mine compound, 2-amino-3,8-dimethylimidazo-[4,5-f]quinoxaline (MelQx), among 47 black, 41 Asian (Chinese or Japanese), and 43 non-Hispanic w hite (white) male residents of Los Angeles County by quantitative anal ysis of total free and conjugated MelQx in pooled overnight urine coll ections. Significant interracial differences were observed. Geometric mean level in blacks was 1.3- and 3.0-fold higher than that in Asians and whites, respectively. Urinary level of MelQx was positively associ ated with intake frequencies of bacon, pork/ham and sausage/luncheon m eats among study subjects, consistent with the observation that in Los Angeles, blacks had the highest consumption of these three food group s among the three races. Among men in Los Angeles County, the incidenc e rates of pancreas and colon cancers, which have been shown to be pos itively related to intake of fried meats, are 50% and 20% higher in bl acks relative to Asians and whites, respectively. Our results are, the refore, consistent with the hypothesis that exposure to heterocyclic a romatic amines is related to risk of pancreas and colon cancers, and m ay in part explain the higher incidence among blacks relative to Asian s and whites in Los Angeles.