No Association between Adherence to a Healthy Nordic Food Index and Colorectal Cancer: Results from a Swedish Cohort Study

Background: Recently, the Nordic diet has gained interest, and a healthy Nordic food index has been developed, which has been found inversely related to colorectal cancer among Danish women. This single finding, however, requires replication in other cohorts. Methods: We conducted a prospective study in the Women's Lifestyle and Health cohort, including 45,222 women, recruited in 1991-92, and followed up ever since through Swedish registries. Participants were classified according to the Nordic food index (consisting of whole grain bread, oatmeal, apples/pears, cabbages, root vegetables, and fish/shellfish), and the association between adherence and colorectal cancer was assessed using the Cox proportional hazards models. Results: In the fully adjusted models, we found no association, neither with the continuous index score [incidence rate ratio (IRR), 1.04; 95% confidence interval (CI), 0.95-1.12, per 1-point increment] nor in the categorical analyses (IRR, 1.09; 95% CI, 0.78-1.52 for highest vs. lowest adherers). Conclusion: The present study does, thus, not support a previous finding of an inverse association between a healthy Nordic food index and colorectal cancer. Impact: This article adds new evidence to the field of the Nordic diet in disease prevention. (C) 2015 AACR.