Dietary heterocyclic amines and the risk of lung cancer among Missouri women

Heterocyclic amines (HCAs) such as 2-amino-3,8-dimethylimidazo[4,5-f]quinox aline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) are found in mea ts cooked at high temperatures. In rodents, MeIQx induces lung turners. The purpose of this study was to investigate lung cancer risk posed by differe nt HCAs in the diet. A population-based case-control study of 593 cases and 623 frequency-matched controls including both nonsmoking and smoking women was conducted in Missouri, An administered food frequency questionnaire wi th detailed questions on meat consumption, degrees of internal doneness, su rface browning/charring, and cooking technique was linked to a database tha t provided exposure estimates of three HCAs. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression. When comparing the 90(th) and 10(th) percentiles, significant excess risks were observed for MeIQx (OR, 1.5; CI, 1.1-2.0), but not fur DiMeIQx (OR, 1. 2; CI, 0.9-1.6) or PhIP (OR, 0.9; CI, 0.8-1.1). MeIQx consumption was assoc iated with increased risk of lung cancer for nonsmokers (OR, 3.6; CI, 1.3-1 0.3) and light/moderate smokers (OR, 2.1; CI, 1.3-3.3), hut not for heavy s mokers (OR, 1.0; CI, 0.7-1.5), There was elevated risk with MeIQx: intake f or subjects with squamous cell carcinomas (OR, 1.9; CI, 1.2-3.1) and "other histological cell types" (OR, 1.6; CI, 1.1-2.5), but not for subjects with small cell carcinomas and adenocarcinomas. Neither DiMeIQx: nor PhIP showe d an association with smoking categories or lung cancer histology, In concl usion, MeIQx may be associated with lung cancer risk, but DiMeIQx and PhIP are probably not associated with lung canter risk.