Meat intake has been inconsistently associated with risk of non-Hodgkin lymphoma (NHL), a heterogeneous group of malignancies of the lymphoid tissue etiologically linked to immunomodulatory factors. In a large U.S. cohort, we prospectively investigated several biologically plausible mechanisms related to meat intake, including meat-cooking and meat-processing compounds, in relation to NHL risk by histologic subtype. At baseline (1995-1996), participants of the NIH-AARP Diet and Health Study completed a diet and lifestyle questionnaire (n = 492,186), and a subcohort (n = 302,162) also completed a questionnaire on meat-cooking methods and doneness levels. Over a mean of 9 y of follow-up, we identified 3611 incident cases of NHL. In multivariable Cox proportional hazards regression models, we found no association between intake of red meat, processed meat, fish, poultry, heme iron, nitrite, nitrate, animal fat, or protein and NHL risk. MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline) and DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline), heterocyclic amines formed in meats cooked to well done at high temperatures, were inversely associated with chronic lymphocytic leukemia/small lymphocytic lymphoma [n = 979; HR (95% CI) for the highest vs. lowest quintile of intake: 0.73 (0.55, 0.96) and 0.77 (0.61, 0.98), respectively]. In this large U.S. cohort, meat intake was not associated with NHL or any histologic subtypes of NHL. Contrary to findings in animal models and other cancer sites, meat-cooking and -processing compounds did not increase NHL risk.
Trial registration: ClinicalTrials.gov NCT00340015.