Objective: We evaluated the effect of meat consumption and cigarette smoking in combination with N-acetyltransferases 1 and 2 (NAT1 and NAT2), and glutathione S-transferase M1 (GSTM1) genotypes on colorectal cancer.
Methods: From a Dutch prospective study, after 8.5 years of follow-up, data of 102 incident colorectal cancer cases and a random sample of 537 controls frequency-matched for gender and age were analyzed. Baseline information on dietary and smoking habits, as well as blood samples for DNA isolation and genotyping, were available.
Results: Red meat intake increased colorectal cancer risk among men (OR 2.7; 95% CI 1.1-6.7 highest vs. lowest intake), whereas poultry and fish decreased risk among women (OR 0.5; 95% CI 0.2-1.07). Cigarette smoking for at least 16 years increased colorectal cancer risk among former smokers only (OR 2.7; 95% CI 1.0-7.4), compared to those having smoked for 15 years or less. NAT1 and NAT2 polymorphisms did not significantly modify these associations. High consumption of poultry and fish was inversely associated with colorectal cancer only in the presence of GSTM1.
Conclusions: In this study meat consumption and former long-term smoking were associated with colorectal cancer. Associations of colorectal cancer with different types of meat were modified by gender and GSTM1 genotype.