Dietary inflammatory index and risk of depressive symptoms: a Cohort study of university students

Diet and lifestyle are modulators of low-grade chronic inflammation, which has been associated with depressive symptoms. This study aimed to examine the association between the dietary inflammatory index (DII) and the risk of depressive symptoms among university students. Data were from 675 students of both sexes, aged between 16 and 25 years old, who entered a Brazilian public university in 2016 and 2017 and were followed up until 2018. The inflammatory potential of the diet was assessed by the DII, which was estimated based on 39 dietary parameters obtained from 24-hour dietary recalls. The presence of depressive symptoms was determined by the Patient Health Questionaire-9, and the cutoff point adopted was ≥ 10 to classify the individuals as 'with' and 'without' depressive symptoms. Generalized linear models with binomial distribution and logarithmic linkage function estimated the relative risk (RR) and confidence intervals (95%CI) of the association between DII and depressive symptoms. The risk for depressive symptoms during follow-up increased for those eating a more inflammatory diet at baseline, reaching an increased risk of 28% in the second year of follow-up (RR = 1.28, 95%CI = 1.06; 1.56). A pro-inflammatory diet contributed to the increased risk of depressive symptoms among university students.