Dietary patterns and colon cancer risk in Whites and African Americans in the North Carolina Colon Cancer Study.

We examined associations of dietary patterns with colon cancer risk in African Americans and Whites from a case-control study in North Carolina. Incident colon cancer cases, 40 to 80 yr (n = 636), and matched controls (n = 1,042) were interviewed in person to elicit information on potential colon cancer risk factors. A validated food frequency questionnaire adapted to include regional foods captured diet over the year prior to diagnosis (cases) or interview date (controls). Three meaningful intake patterns were identified in both Whites and African Americans: "Western-Southern," "fruit-vegetable," and "metropolitan." Compared to the Western-Southern pattern, the fruit-vegetable and metropolitan patterns were associated with more healthful dietary behaviors (e.g., higher vegetable intake and lower red meat consumption), and demographic/lifestyle characteristics typically correlated with low colon cancer risk, for example, lower BMI, higher education, and higher NSAID use. The fruit-vegetable pattern was significantly inversely associated with colon cancer risk in Whites (OR = 0.4, 95% CI = 0.3-0.6) and the metropolitan pattern with a nonsignificant 30% risk reduction in both Whites and African Americans after adjustment for education. The Western-Southern pattern was not associated with colon cancer risk. These findings may explain some of the racial differences in colon cancer incidence and underscore the importance of examining diet-cancer associations in different population subgroups.