A prospective study of meat, cooking methods, meat mutagens, heme iron, and lung cancer risks

Background: Red and processed meat consumption may play a role in lung cancer pathogenesis because of these meats' fat and carcinogen content. Objective: We prospectively investigated whether meat type, cooking method, doneness level, and intake of specific meat mutagens and heme iron are associated with lung carcinoma. Design: Men (n = 278,380) and women (n = 189,596) from the National Institutes of Health-AARP Diet and Health Study with no history of cancer at baseline were monitored for 8 y. Diet was assessed with a 124-item food-frequency questionnaire. A meat-cooking module was used to estimate the intake of individual heterocyclic amines, benzo(a) pyrene, and heme iron. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs. Results: In a comparison of quintiles 5 with 1 (Q5vsQ1), a high intake of red meat was associated with an increased risk of lung carcinoma in both men (HRQ5vsQ1: 1.22; 95% CI: 1.09, 1.38; P for trend = 0.005) and women (HRQ5vsQ1: 1.13; 95% CI: 0.97, 1.32; P for trend = 0.05). A high intake of processed meat increased the risk only in men (HRQ5vsQ1: 1.23; 95% CI: 1.10, 1.37; P for trend = 0.003). In an analysis stratified by smoking status, we observed a tendency for an increased risk with red meat intake in never smoking men and women; however, the risks were not statistically significant. In a comparison of tertiles 3 and 1 (T3vsT1), the risk of lung carcinoma was associated with intake of well-/very-well-done meat (HRT3vsT1: 1.20; 95% CI: 1.07, 1.35; P for trend = 0.002) and the intake of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (HRQ5vsQ1: 1.20; 95% CI: 1.04, 1.38; P for trend = 0.04) in men. Heme iron intake increased the risk of lung carcinoma in both men (HRQ5vsQ1: 1.25; 95% CI: 1.07, 1.45; P for trend = 0.02) and women (HRQ5vsQ1: 1.18; 95% CI: 0.99, 1.42; P for trend = 0.002). Conclusion: We observed a moderate association between meat consumption and lung carcinoma, which might be explained by heme iron intake, high-temperature cooking, and associated mutagens. Am J Clin Nutr 2009; 89: 1884-94.