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Habibul Ahsan,^1,2 Li-Yu Wang,³ Chien-Jen Chen,⁴ Wei-Yann Tsai,⁵ and Regina M. Santella^2,3

¹Department of Epidemiology, Columbia University, New York, New York, USA; ²Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York, USA; ³Department of Environmental Health Sciences, Columbia University, New York, New York, USA; ⁴Institute of Epidemiology of College of Public Health, National Taiwan University, Taiwan; ⁵Department of Biostatistics, Columbia University, New York, New York, USA

Abstract

Exposure to aflatoxin B₁ (AFB₁) , an important cofactor in the etiology of hepatocellular carcinoma in Taiwan, is influenced by dietary and other factors. The present study examined the intraindividual variability in AFB₁-albumin adducts, the most reliable long-term biomarker of AFB₁ exposure, and whether the baseline or follow-up adduct levels and the intraindividual variability in adduct levels are modified by endogenous and environmental factors. The study measured AFB₁-albumin adduct levels among 264 healthy male residents of three townships (Hu-Hsi, Ma-Kung, and Pai-Hsa) of Penghu Islets, Taiwan, at two different time points with a median interval of 1.68 years (range 1.00-3.17 years) . There was a generalized reduction in the adduct levels, with the median values being 22.1 pmol/mg (range 5.0-355.8 pmol/mg) at time 1 and 14.3 pmol/mg (range 5.0-205.2 pmol/mg) at time 2. This intraindividual variability in adduct levels was inversely associated with the age of subjects and the time interval between the two blood draws. The variability in adduct levels was lower among subjects in Hu-Hsi and Pai-Hsa townships as compared to those in Ma-Kung. No significant association was observed for the intraindividual variability in AFB₁-albumin adducts with regard to the season when blood was drawn. There was also no significant association between intraindividual variability and hepatitis B surface antigen, anti-hepatitis C virus (anti-HCV) , glutathione S-transferase (GST) M1, or GSTT1 status. In conclusion, we found substantial intraindividual variability in the AFB₁ exposure (as determined by AFB₁-albumin adducts) in Taiwan, which was probably more likely related to dietary or other environmental influences rather than to endogenous factors (e.g., hepatitis B/C viral infection or GST M1/T1 genetic status) . Key words: aflatoxin-albumin adducts, biomarkers, intraindividual variability, liver cancer, molecular epidemiology. Environ Health Perspect 109:833-837 (2001) . [Online 13 August 2001]

http://ehpnet1.niehs.nih.gov/docs/2001/109p833-837ahsan/ abstract.html

Address correspondence to H. Ahsan, Division of Epidemiology, Room PH-18-129, Columbia-Presbyterian Medical Center, 622 West 168th Street, New York, NY 10032 USA. Telephone: (212) 305-7636. Fax: (212) 305-9413. E-mail: ha37@columbia.edu

This work was partially supported by National Institute of Environmental Health Sciences grants R01ES05116-6 and P30ES09089.

Received 4 October 2000 ; accepted 26 February 2001.