Intake of Red and Processed Meat, Use of Non-Steroid Anti-Inflammatory Drugs, Genetic Variants and Risk of Colorectal Cancer: A Prospective Study of the Danish "Diet, Cancer and Health" Cohort.

Red and processed meat have been associated with increased risk of colorectal cancer (CRC), whereas long-term use of non-steroid anti-inflammatory drugs (NSAIDs) may reduce the risk. The aim was to investigate potential interactions between meat intake, NSAID use, and gene variants in fatty acid metabolism and NSAID pathways in relation to the risk of CRC. A nested case-cohort study of 1038 CRC cases and 1857 randomly selected participants from the Danish prospective "Diet, Cancer and Health" study encompassing 57,053 persons was performed using the Cox proportional hazard model. Gene variants in , , , , , , , , , and were investigated. rs6983267 was associated with the risk of CRC per se ( < 0.01). Statistically significant interactions were found between intake of red and processed meat and rs6983267, rs1042522, rs7737692, rs7623023 ( = 0.04, 0.04, 0.02, 0.03, respectively), and the use of NSAID and alcohol intake and rs1042522 ( = 0.04, 0.04, respectively) in relation to the risk of CRC. No other consistent associations or interactions were found. This study replicated an association of rs6983267 with CRC and an interaction between rs1042522 and NSAID in relation to CRC. Interactions between genetic variants in fatty acid metabolism and NSAID pathways and the intake of red and processed meat were found. Our results suggest that meat intake and NSAID use affect the same carcinogenic mechanisms. All new findings should be sought replicated in independent prospective studies. Future studies on the cancer-protective effects of aspirin/NSAID should include gene and meat assessments.