Lower intensity of physical activity strengthens the effect of dietary inflammatory index on the risk of all-cause and cause-specific mortality

To examine the independent and joint associations of dietary inflammation index (DII) and physical activity (PA) with mortality risk. We analyzed data for 20,165 study participants aged ≥ 18 from The Rural Chinese Cohort Study. The Cox proportional hazard model was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) of mortality associated with DII and PA. The dose-response association between DII and mortality risk was intuitively generated by the restricted cubic splines model. During the mean 5.03-year follow-up, a total of 1110 cases of all-cause mortality were identified. Compared with people in quartile 1 of DII, positive associations were found in quartile 4 for all-cause (HR 1.27; 95%CI 1.06-1.52), CVD (HR 1.45; 95%CI 1.09-1.91), and other mortality (HR 1.52; 95%CI 1.10-2.09), while a linear association was demonstrated. Compared with people of quartile 1 of DII and high intensity of PA, those with quartile 4 of DII and low intensity of PA had higher risk of all-cause (HR 1.96; 95%CI 1.50-2.56), CVD (HR 2.68; 95%CI 1.71-4.19), and other mortality (HR 1.83; 95%CI 1.19-2.83). A pro-inflammatory diet was significantly associated with increased risk of mortality and lower PA may strengthen the effect.