Meat preparation and colorectal adenomas in a large sigmoidoscopy-based case-control study in California (United States)

The often observed association between red meat and colorectal cancercould be due in part to mutagens, such as heterocyclic amines (HCA), that arepresent in cooked meat. HCAs are highly mutagenic and cause intestinal tumorsin animals. The hypothesis that HCAs are also carcinogenic to humans remainsto be substantiated in epidemiologic studies. We determined the associationsof meat preparation and frequency of intake (proxy variables for HCAexposure, since HCA concentration depends on the type of meat and the way itis cooked) with the prevalence of distal colorectal adenomas in asigmoidoscopy-based case-control study of 488 matched pairs of subjects fromtwo California (United States) Kaiser Permanente Medical Centers. A more thantwofold difference in adenoma prevalence between subjects at extreme ends ofestimated HCA intake was observed. For subjects who ate red meat more thanonce per week, fried it more than 10 percent of the time, and ate it with adarkly browned surface, compared with subjects who ate red meat one time orless per week, fried it 10 or less percent of the time, and ate it with alightly browned surface, the odds ratio was 2.2 (95 percent confidenceinterval = 1.1-4.3). Adenoma prevalence also increased with frequency offrying red meat (P trend = 0.004). These results are consistent with acarcinogenic effect of HCA.