Association between the empirical dietary inflammatory index and cardiorespiratory fitness in Tehranian adults in 2017–2018

BACKGROUND: Inflammatory-related chronic diseases are increasing in Iran with high consumption of a diet containing pro-inflammatory potential and a sedentary lifestyle. The empirical dietary inflammatory index (EDII) was developed as a tool to assess dietary effects on systemic inflammation. We examined the hypothesis that specific dietary patterns reflecting systemic inflammation are associated with cardiorespiratory fitness (CRF) in Tehranian adults. METHODS: This cross-sectional study was carried out on 270 adults who are residents of Tehran. Dietary intake was assessed using a 168-item valid and reliable food frequency questionnaire. The EDII score was developed according to participant dietary intakes of 21-item pre-defined food groups. CRF was assessed by using a graded exercise treadmill test. Anthropometric measurements were assessed using standard methods. To discover the association between CRF and EDII, we used multivariable logistic regression analysis. RESULTS: Those who were in the third tertile of the EDII had 57% lower odds of having better VO(2Max) (ml/kg/min) than those in the first tertile (OR: 0.43; 95% CI: 0.16, 1.12, p = 0.01). There were no significant differences between tertiles of the EDII score in terms of VO2 (L·min) and VO2 (LBM) before and after adjusting for confounders. There was a significant decrease in VO(2Max) (ml/kg/min) across tertiles of the EDII after controlling for covariates (p-value = 0.04). There was a significant inverse association between the EDII score and VO(2Max) (ml/kg/min) (β = −0.35, p = 0.001). CONCLUSIONS: Our finding demonstrated that a higher EDII might be associated with lower CRF in Tehranian adults. Prospective studies are needed to shed light on the causal link between the EDII and CRF.