Colorectal cancer (CRC) is a multi-factorial disease in which diet is believed to play a role. Little is known about the health effects of specific regional diets. The Nordic diet is high in fat and sugar but also includes a range of traditional products with anticipated health-promoting effects. The aim of this cohort study was to determine whether a healthy Nordic food index consisting of fish, cabbage, rye bread, oatmeal, apples, pears and root vegetables was related to CRC incidence. Data were obtained from a prospective cohort study of 57,053 Danish men and women aged 50-64 years, of whom 1025 developed CRC (13 years' follow-up). Incidence rate ratios (IRR) with 95 % CI were calculated from Cox proportional hazard models. Women who strongly adhered to a healthy Nordic food index had a 35 % lower incidence of CRC than women with poor adherence (adjusted IRR, 0·65; 95 % CI 0·46, 0·94); a similar tendency was found for men. Women had a 9 % lower incidence of CRC per point adherence to the healthy Nordic food index, but no significant effect was found for men. A regional diet based on healthy Nordic food items was therefore associated with a lower incidence of CRC in women. The protective effect was of the same magnitude as previously found for the Mediterranean diet, suggesting that healthy regional diets should be promoted in order to ensure health; this will also preserve cultural heredity and the environment.
Epidemiological studies show that non-steroidal anti-inflammatory drugs (NSAIDs) reduce colorectal cancer incidence. We measured the rate ratio for colorectal adenocarcinoma according to dosage and the timing of exposure by means of a case-control study, nested in a non-concurrent cohort linkage study, using the population of beneficiaries of the Saskatchewan Prescription Drug Plan from 1981 to 1995 with no history of cancer since 1970 as the source population. Four controls per case, matched on age and gender and alive when the case was diagnosed, were randomly selected. Dispensing rates, calculated over successive time periods, characterized NSAID exposure. We accrued 3844 cases of colon cancer and 1971 cases of rectal cancer. For colon cancer a significant trend towards a decreasing rate ratio was associated with increasing exposure during the 6 months preceding diagnosis (P-trend = 0.002). For both cancers, significant trends were associated with exposure 11-15 years before diagnosis (colon: P-trend = 0.01; rectum: P-trend = 0.0001). At the highest exposure levels the rate ratio for colon cancer was 0.57 (95% confidence interval (CI) 0.36-0.89); for rectal cancer it was 0.26 (95% CI 0.11-0.61). No protection was associated with exposure during other periods. The timing of NSAID use must be considered in planning intervention trials to prevent colorectal cancer. There may be a 10-year delay before any preventive effect will appear.
BACKGROUND: Micronutrients may protect against colorectal cancer. Especially folate has been considered potentially preventive. However, studies on folate and colorectal cancer have found contradicting results; dietary folate seems preventive, whereas folic acid in supplements and fortification may increase the risk. OBJECTIVE: To evaluate the association between intake of vitamins C, E, folate and beta-carotene and colorectal cancer risk, focusing on possibly different effects of dietary, supplemental and total intake, and on potential effect modification by lifestyle factors. DESIGN: In a prospective cohort study of 56,332 participants aged 50-64 years, information on diet, supplements and lifestyle was collected through questionnaires. 465 Colon and 283 rectal cancer cases were identified during follow-up. Incidence rate ratios of colon and rectal cancers related to micronutrient intake were calculated using Cox proportional hazard analyses. RESULTS: The present study found a protective effect of dietary but not supplemental folate on colon cancer. No association with any other micronutrient was found. Rectal cancer did not seem associated with any micronutrient. For both colon and rectal cancer, we found an interaction between dietary folate and alcohol intake, with a significant, preventive effect among those consuming above 10g alcohol/day only. CONCLUSIONS: This study adds further weight to the evidence that dietary folate protects against colon cancer, and specifies that there is a source-specific effect, with no preventive effect of supplemental folic acid. Further studies should thus take source into account. Vitamins C, E and beta-carotene showed no relation with colorectal cancer.