Postdiagnostic mediterranean and healthy nordic dietary patterns are inversely associated with all-cause mortality in long- term colorectal cancer survivors

Abstract

Background: Dietary factors are known to affect the risk of new-onset colorectal cancer (CRC), but information on the extent to which postdiagnostic diet affects mortality in long-term CRC survivors is scarce. Objective: We investigated the association of 2 a priori-defined postdiagnostic dietary patterns [Modified Mediterranean Diet Score (MMDS) and healthy Nordic Food Index (HNFI)] with all-cause mortality in long-term CRC survivors. Methods: Diet was assessed at a median time of 6 y after cancer diagnosis in 1404 CRC survivors (median age: 69 y; 56% men) in a prospective cohort study in Northern Germany by using a semiquantitative food-frequency questionnaire. Cox proportional hazard models, adjusting for clinical and sociodemographic characteristics, were used to assess associations of the MMDS and the HNFI with all-cause mortality. Results: A total of 204 patients died during a median follow-up time of 7 y after diet assessment. In multivariable-adjusted models, higher adherence to the modified Mediterranean diet was significantly associated with lower all-cause mortality (HR: 0.48; 95% CI: 0.32, 0.74 for highest compared with lowest score quartile and HR: 0.88; 95% CI: 0.81, 0.96 per 1-point increment in pattern score). Similarly, the HNFI was inversely associated with all-cause mortality when the highest was compared with the lowest index quartile (HR: 0.63; 95% CI: 0.39, 1.04) and when modeled as a continuous trait (HR: 0.90; 95% CI: 0.82, 0.99 per 1-point increment in the score). Conclusions: Our results suggest that higher adherences to the Mediterranean diet and to the healthy Nordic diet after CRC diagnosis are associated with better overall survival in long-term CRC survivors.