Meat and heme iron intake and risk of squamous cell carcinoma of the upper aero-digestive tract in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Background: Evidence from prospective studies on intake of meat and fish and risk of squamous cell carcinoma (SCC) of the upper aero-digestive tract (UADT) is scarce. We prospectively investigated the association of meat and fish intake with risk of SCC of the UADT and the possible mechanism via heme iron in the large multicenter European Prospective Investigation into Cancer and Nutrition (EPIC) study. Methods: Multivariable proportional hazards models were used to estimate relative risks (RR) of SCC of the UADT in relation to intake of total meat, as well as subtypes of meat, fish, and heme iron among 348,738 individuals from 7 European countries. Results: During an average follow-up of 11.8 years, a total of 682 incident cases of UADT SCC were accrued. Intake of processed meat was positively associated with risk of SCC of the UADT in the total cohort [highest vs. lowest quintile: RR = 1.41; 95% confidence interval (CI) = 1.03-1.94], however, in stratified analyses, this association was confined to the group of current smokers (highest vs. lowest quintile: RR = 1.89; 95% CI = 1.22-2.93). Red meat, poultry, fish, and heme iron were not consistently related to UADT SCC. Conclusion: Higher intake of processed meat was positively associated with SCC of the UADT among smokers. Although this finding was stable in various sensitivity analyses, we cannot rule out residual confounding by smoking. Confirmation in future studies and identification of biologic mechanisms is warranted. Impact: Smokers may further increase their risk for SCC of the UADT if they additionally consume large amounts of processed meat.