Influence of anti-inflammatory diet and smoking on mortality and survival in men and women: two prospective cohort studies

Abstract

Background: The associations between an anti-inflammatory diet and both all-cause and cause-specific mortality have been studied previously; however, the influence of an anti-inflammatory diet on survival time has not been investigated. Moreover, the potential modification of these associations by smoking status remains unclear.

Objective: The aims of this study were to examine the associations between an anti-inflammatory diet index (AIDI) and all-cause and cause-specific mortality, to determine the association between the AIDI and differences in survival time and to assess effect modification by smoking status.

Methods: The study population included 68 273 Swedish men and women (aged 45-83 years) at baseline. The anti-inflammatory potential of the diet was estimated using the validated AIDI, which includes 11 potential anti-inflammatory and five potential pro-inflammatory foods. Cox proportional hazards and Laplace regression were used to estimate hazard ratios and differences in survival time.

Results: During 16 years of follow-up (1 057 959 person-years), 16 088 deaths [5980 due to cardiovascular disease (CVD) and 5252 due to cancer] were recorded. Participants in the highest versus lowest quartile of the AIDI had lower risks of all-cause (18% reduction, 95% CI: 14-22%), CVD (20%, 95% CI: 14-26%) and cancer (13%, 95% CI: 5-20%) mortality. The strongest inverse associations between the highest and lowest quartiles of AIDI and risk of mortality were observed in current smokers: 31%, 36% and 22% lower risks of all-cause, CVD and cancer mortality, respectively. The difference in survival time between current smokers in the lowest AIDI quartile and never smokers in the highest quartile was 4.6 years.

Conclusion: Adherence to a diet with high anti-inflammatory potential may reduce all-cause, CVD and cancer mortality and prolong survival time especially amongst smokers.

Keywords: anti-inflammatory index; diet; inflammation; mortality; prospective study; survival time.