An evaluation of the Dietary Guidelines for Americans in relation to cancer occurrence

Background: Although scientific knowledge regarding the influence of nutritional factors on health and disease serves as the basis for specific recommendations included in the Dietary Guidelines for Americans, limited empirical epidemiologic data are available to verify that adherence to the cluster of nutrition-related behaviors included in the Dietary Guidelines will reduce the incidence of disease. Objective: We examined the association of compliance with the Dietary Guidelines and incident cancers. Design: Data from a population-based cohort of postmenopausal women (n = 34 708) were examined. A dietary guidelines index was derived as a summary measure of compliance with the Dietary Guidelines, and the association of this index and cancer incidence was examined for all cancers combined and for site-specific cancers with > 100 events. Results: For all cancers combined, the relative risks associated with the upper 4 quintiles of the dietary guidelines index in reference to the bottom quintile were 0.95 (95% CI: 0.87, 1.05) for quintile 2, 0.88 (95% CI: 0.80, 0.97) for quintile 3, 0.88 (95% CI: 0.80, 0.96) for quintile 4, and 0.85 (95% CI: 0.77, 0.93) for quintile 5 (P for trend < 0.01). Similar patterns in relative risks were found for cancers of the colon, bronchus and lung, breast, and uterus. In contrast, ovarian cancer incidence was positively associated with the dietary guidelines index. Conclusion: Our findings suggest that adherence to the cluster of nutrition-related behaviors included in the Dietary Guidelines for Americans may be associated with a lower risk of cancer.