Association between dietary inflammatory index, and cause-specific mortality in the MONICA/KORA Augsburg Cohort Study

Background: Chronic diseases such as cancer and cardiovascular diseases (CVDs) are well-established causes of disability and premature death. Dietary components have been implicated in the etiology of these chronic diseases. Methods: We examined the ability of the Dietary Inflammatory Index (DIITM) to predict all-cause, coronary heart disease (CHD), CVD and cancer mortality and incident CHD in the MONICA-KORA Cohort Studies. DII scores were computed from baseline 7-day dietary records in this cohort of 1297 men, who were aged 45-64 years when enrolled. During the follow-up period, 551 total (155 CHD, 244 CVD and 175 cancer-related deaths) and 213 validated incident CHD events were identified through mortality record linkage and active follow-up. Spearman correlation coefficients were calculated between DII scores and the inflammatory marker C-reactive protein (CRP). Cox proportional hazards regression was used to estimate hazard ratios (HR) for the endpoints described above. Results: DII scores were significantly positively correlated with CRP (P value <0.0001). Positive associations were noted between DII and all-cause mortality (HRQ4vsQ1: 1.41; 95%CI 1.04-1.90; P-trend = 0.007) and incident CHD (HRQ4vsQ1: 1.83; 95%CI 1.12-3.01; P-trend = 0.008). These associations were attenuated after further adjustment for smoking status, but remained significant for all-cause mortality. When stratified by smoking status, DII was associated with all-cause and cancer mortality among ex-smokers, in the absence of significant heterogeneity. Conclusion: These results indicate that a pro-inflammatory diet as expressed by higher DII scores is associated with all-cause mortality. This association was more pronounced among ex-smokers in whom a significant association with cancer mortality was observed.