Association between inflammatory potential of diet and mortality among women in the Swedish Mammography Cohort

Nitin Shivappa, Holly Harris, Alicja Wolk, James R. Hebert

Diet and dietary components have been studied previously in relation to mortality; however, little is known about the relationship between the inflammatory potential of overall diet and mortality. We examined the association between the Dietary Inflammatory Index (DII) and mortality among 33,747 participants in the population-based Swedish Mammography Cohort. The DII score was calculated based on dietary information obtained from a self-administered food frequency questionnaire. Mortality was determined through linkage to the Swedish Cause of Death Registry through 2013. Cox proportional hazard regression was used to estimate hazard ratios (HR). During 15 years of follow-up, 7095 deaths were identified, including 1996 due to cancer, 602 of which were due to digestive-tract cancer, and 2399 due to cardiovascular disease. After adjusting for age, energy intake, education, alcohol intake, physical activity, BMI, and smoking status, analyses revealed a positive association between higher DII score and all-cause mortality. When used as a continuous variable (range -4.19 to 5.10), DII score was associated with all-cause mortality (HRContinuous = 1.05; 95 % CI 1.01-1.09) and digestive-tract cancer mortality (HRContinuous = 1.15; 95 % CI 1.02-1.29). Comparing subjects in the highest quintile of DII (≥1.91) versus the lowest quintile (DII ≤ -0.67), a significant association was observed for all-cause mortality (HR = 1.25; 95 % CI 1.07-1.47, P trend = 0.003). These results indicate that a pro-inflammatory diet, as indicated by higher DII score, was associated with all-cause and digestive-tract cancer mortality.