Dietary intake of heterocyclic amines and cancers of the esophagus and gastric cardia.

The results of two epidemiological studies suggest that high intake of heterocyclic amines, which are formed on the surface of meats cooked at high temperatures, might be associated with increased risk of esophageal or cardia cancers. Our aim was to further investigate heterocyclic amine intake and risk of these cancers. We examined data from a nationwide, population-based, case-control study of risk factors for adenocarcinoma of the esophagus and gastric cardia and squamous cell carcinoma of the esophagus in Sweden, with 185, 258, and 165 cases, respectively, and 815 controls. Heterocyclic amine intake was estimated based on the frequency of consumption and degree of surface browning of commonly fried meats, and the consumption of pan juices. Statistically nonsignificant 50-70% higher risks of esophageal squamous cell carcinoma were observed among individuals in the highest quartile levels of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, and 2-amino-1methyl-6-phenylimidazo[4,5-b]pyridine relative to those in the lowest. Dose-risk trends were evident. Subjects reporting high intake of all three heterocyclic amines had an odds ratio of 2.4 (95% confidence interval, 1.2-4.8) relative to those with low intake of all three substances. In contrast, no association was found with risk of adenocarcinoma of the esophagus or gastric cardia. Heterocyclic amine intake might be associated with an increase in risk of squamous cell carcinoma of the esophagus. Given the dearth of epidemiological data regarding these cancers and the lack of established biological mechanisms, confirmatory data are needed.