Aflatoxin Exposure in Singapore: Blood Aflatoxin Levels in Normal Subjects, Hepatitis B Virus Carriers and Primary Hepatocellular Carcinoma Patients

Blood screening conducted on Singaporeans over 1991–1992 showed exposure to predominately aflatoxin B1 and to a lesser extent G1.The extent of exposure to B1 among three groups of residents in Singapore, namely normal subjects (n = 423), hepatitis B virus carriers (n = 302) and primary hepatocellular carcinoma (PHC) patients (n = 58) were extensive as reflected by the positive rates of 15.1, 0.7 and 1.7 per cent respectively. However, the degree of individual exposure to this toxin among the three groups was considered low as shown by the low respective mean blood levels of 5.4 ± 3.2 (range 3.0–17), 7.7 (range 7.5–7.9) and 7.5 picogrammes per ml of blood. It is not immediately clear whether or not such low levels would precipitate an undesirable health effect. The higher positive rate seen in normal subjects as compared with the other groups could be due to differences in dietary intake of aflatoxin B1, differences in metabolic patterns or both. About 70 per cent of PHC patients studied were carriers.The ...