ARE DIETARY FACTORS INVOLVED IN DNA METHYLATION ASSOCIATED WITH COLON-CANCER

Disturbances in DNA methylation have been hypothesized as being involv ed bt carcinogenesis. It has been proposed that dietary factors such a s folate, alcohol, and methionine I?tay be associated with colon cance r because of their involvement in DNA methylation processes. Data from a targe retrospective population-based case-control study of incident colon cancer were used to evaluate whether intake of alcohol and othe r dietary factors involved in DNA methylation are associated with colo n cancer. Dietary data were obtained using a detailed diet history que stionnaire. We did not observe strong independent associations between folate, vitamin B-6, vitamin B-12, methionine, or alcohol and risk of colon cancer after adjusting far body size, physical activity, cigare tte smoking patterns, energy intake, and dietary intake of fiber and c alcium. However, it hen assessing the associations between colon cance r and a composite dietary profile based on alcohol intake, methionine, folate, vitamin B-12, and vitamin B-6, we observed a trend of increas ing risk as one moved from a low- to a high-risk group. This trend was modest and most marked in those diagnosed at a younger age [odds rati o (OR) for men = 1.3, 95% confidence interval (CI) = 0.9-1.9; OR for w omen = 1.6, 95% CI = 1.0-2.6]. We observed that associations with this high-risk dietary profile were greater among those who took aspirin o r nonsteroidal anti-inflammatory drugs on a regular basis and were you nger at the time of diagnosis (men OR = 1.7, 35% CI = 1.0-3.2; women O R = 2.2, 95% CI = 1.0-4.8) and for distal tumors (men OR = 1.4 95% CI = 0.9-2.3; women OR = 2.0, 95% CI = 1.0-3.8). Findings from this study provide only limited support for previously reported associations bet ween dietary factors involved in DNA methylation and risk of colon can cer.