A CASE-CONTROL STUDY OF DIET AND COLORECTAL-CANCER IN A MULTIETHNIC POPULATION IN HAWAII (UNITED-STATES) - LIPIDS AND FOODS OF ANIMAL ORIGIN

Temporal trend and migrant studies have indicated-that the etiology of colorectal cancer is predominantly environmental and, hence, modifiab le. Animal fat intake has been frequently, but inconsistently, associa ted with the risk of this disease. We conducted a population-based cas e-control study in Hawaii (United States) among ethnic groups at diffe rent risks of the disease to evaluate the role of dietary lipids and f oods of animal origin on the risk of colorectal cancer. We interviewed 698 male and 494 female Japanese, Caucasian (White), Filipino, Hawaii an, and Chinese patients diagnosed during 1987-91 with pathologically confirmed adenocarcinoma of the colon or rectum, and 1,192 population controls matched to cases on age, gender and ethnicity. Odds ratios (O R), adjusted for caloric intake and other dietary and non-dietary risk factors, were estimated using conditional logistic regression. Intake s of total fat, saturated fat (S) and polyunsaturated fat (P) were not related to the risk of colorectal cancer. However, an inverse associa tion was found for the P/S ratio, with ORs of 0.6 in both genders (95 percent confidence interval [CI] = 0.4-1.0 for males; CI = 0.3-0.9 far females) for the highest compared with the lowest quartile (P less th an or equal to 0.05 for trend). Intakes of red meat and processed meat were associated with the risk of cancer in the right colon and rectum , respectively, in men only. Fat-trimmed red meat and fish intakes wer e not related to risk. Chicken eaten without skin was associated inver sely with risk in both genders. The strongest association was found fo r eggs, with an OR of 2.7 (CI = 1.7-4.0) and 2.3 (CI = 1.4-3.7) for th e highest compared with the lowest quartile of intake in men and women , respectively (P < 0.001 for trend). This association was dose-depend ent, not explained by known confounders or other dietary variables, an d was very consistent between genders, among ethnic groups, and across all segments of the large bowel. These data suggest that the ratio of polyunsaturated to saturated fat may be a better indicator of colorec tal cancer risk than the absolute amount of specific fats in the diet. They also suggest that eggs and, possibly, untrimmed red meat and pro cessed meat increase, and chicken eaten without skin decreases, colore ctal cancer risk.