Tobacco Smoking and Urinary Levels of 2-Amino-9H-Pyrido[2,3-b]Indole in Men of Shanghai, China

Abstract

Carcinogenic heterocyclic aromatic amines (HAA) are formed in cooked meats, poultry, and fish and arise in tobacco smoke. We measured the concentrations of four prevalent HAAs in spot urine samples collected at baseline from 170 participants of the Shanghai Cohort study, a population-based cohort study of adult men recruited during 1986 to 1989 in Shanghai, China. Sixteen (18.6%) of 86 nonsmokers were positive for urinary 2-amino-9H-pyrido[2,3-b]indole (AAC) versus 41 (48.8%) of 84 cigarette smokers; the difference was statistically significant (P < 0.001). The number of cigarettes smoked per day was positively and significantly related to urinary levels of AAC in study subjects (P < 0.001); the mean level among nonsmokers was 2.54 ng/g creatinine, whereas the means for light (1-19 cigarettes per day) and heavy (20+ cigarettes per day) smokers were 7.50 and 11.92 ng/g creatinine, respectively. 2-Amino-3,4,8-trimethylimidazo [4,5-f] quinoxaline was undetected in the urine of the 170 subjects. Only 5 (2.9%) and 6 (3.5%) subjects, respectively, showed detectable levels of urinary 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine and 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline, and smoking status was unrelated to levels of either HAA. Quantitative measurements of HAAs in commonly eaten pork and chicken dishes in Shanghai showed low concentrations of HAAs (<1 ng/g meat). Our data indicate that AAC represents a major HAA exposure in adult men of Shanghai, China, and that tobacco smoke is an important point source of their AAC exposure. (Cancer Epidemiol Biomarkers Prev 2007;16(8):1554 -60)

Biomarkers of Tobacco Exposure: Summary of an FDA-Sponsored Public Workshop

“…Urinary levels of ortho-toluidine, 1-naphthylamine, 2-naphthylamine, 3-aminobiphenyl, and 4-aminobiphenyl are typically low; studies reporting these biomarkers do not consistently differentiate smokers from non-smokers. Similarly, urinary levels of all heterocyclic amines with exception of 2-amino-1,7-dimethylimidazo[4,5-b]pyridine (DMIP) and 2-amino-9H-pyrido[2,3-b]indole (AαC) do not differentiate smokers and non-smokers (77, 79). In contrast, hemoglobin adducts of 3-aminobiphenyl, 4-aminobiphenyl, and dimethylanilines are significantly elevated in smokers compared to non-smokers (77, 80–82).…”

Prospective study of dietary patterns and colorectal cancer among Singapore Chinese

“…Differences in meat cooking methods between Western and Asian populations may be another reason for the discrepancy. For example, in the US consuming grilled meat is a major source of exposure to the colorectal mutagens, heterocyclic amines (Bogen and Keating, 2001), whereas these are at non-detectable levels among Chinese populations, where stir frying is the preferred meat cooking method (Turesky et al, 2007).…”

2-Amino-9H-pyrido[2,3-b]indole (AαC) Adducts and Thiol Oxidation of Serum Albumin as Potential Biomarkers of Tobacco Smoke

“…Apart from the endocyclic nitrogen atoms, A␣C shares the same structure as 2-aminofluorene, one of the most well studied aromatic amine carcinogens (10). Significant levels of A␣C were detected in the urine of male smokers of the Shanghai cohort in China, providing evidence that tobacco smoke is a major source of A␣C exposure (11). A␣C is a liver carcinogen in mice, a transgene colon mutagen, and an inducer of colonic aberrant crypt foci, an early biomarker of colon neoplasia (12)(13)(14).…”