Meat, cooking methods and colorectal cancer: a case-referent study in Stockholm.

The associations between methods of cooking meats and colorectal cancer were examined in a population-based case-referent study performed in Stockholm in 1986-1988. The study included 559 cases and 505 referents. Total meat intake, frequent consumption of brown gravy, and a preference for a heavily browned meat surface each independently increased the risk for colorectal cancer. The relative risks (RR) were higher for rectal than for colon cancer, and for boiled meat (RR colon = 1.7, RR rectum = 2.7) than for meat fried with a medium or lightly browned surface (RR colon = 0.8, RR rectum = 1.1), but the highest risks were for meat fried with a heavily browned surface (RR colon = 2.8, RR rectum = 6.0). The analyses were adjusted for year of birth, gender and fat intake. Further adjustments for total energy, dietary fiber intake, body mass and physical activity had little or no influence on the results. The findings suggest that, in addition to frequent meat intake, a heavily browned meat surface formed when frying meat at high temperatures is important in the etiology of colorectal cancer.