FOOD GROUPS AND RISK OF COLORECTAL-CANCER IN ITALY

The proportion of colorectal cancer attributed to dietary habits is hi gh, but several inconsistencies remain, especially with respect to the influence of some food groups. To further elucidate the role of dieta ry habits, 1,225 subjects with cancer of the colon, 728 with cancer of the rectum and 4,154 controls, hospitalized with acute non-neoplastic diseases, were interviewed between 1992 and 1996 in 6 different Itali an areas. The validated food-frequency questionnaire included 79 quest ions on food items and recipes, categorised into 16 food groups. After allowance for non-dietary confounding factors and total energy intake , significant trends of increasing risk of colorectal cancer with incr easing intake emerged for bread and cereal dishes (odds ratio [OR] in highest vs. lowest quintile = 1.7), potatoes (OR = 1.2), cakes and des serts (OR = 1.1), and refined sugar (OR = 1.4). Intakes of fish (OR = 0.7), raw and cooked vegetables (OR = 0.6 for both) and fruit other th an citrus fruit (OR = 0.7) showed a negative association with risk. Co nsumption of eggs and meat (white, red or processed meats) seemed unin fluential. Most findings were similar for colon and rectum, but some n egative associations (i.e., coffee and tea, and fish) appeared stronge r for colon cancer. Our findings lead us to reconsider the role of sta rchy foods and refined sugar in light of recent knowledge on the diges tive physiology of carbohydrates and the insulin/colon cancer hypothes is. The beneficial role of most vegetables is confirmed, with more tha n 20% reduction in risk of colorectal cancer from the addition of one daily serving. (C) 1997 Wiley-Liss, Inc.