Background and Objectives: The body composition and cardiorespiratory fitness are two important factors that reflect nutritional and physical activity status, respectively. An increase in the body fat stores can lead to systemic inflammation. The aim of this study was investigating the relationship of plasma IL-18 with cardiorespiratory fitness, body composition, lipid profile and dietary composition.

Materials and Methods: Ninety (37 women, 53 men) employees of Islamic Azad University, Ahvaz branch (BMI> 25 kg/m2) were enrolled in the present study, The bioelectrical impedance was used for the measurement of body composition.  cardiorespiratory fitness was measured by Forestry step test, and the 24-hour recall questionnaires used for evaluation of dietary composition. The lipid profile, fasting sugar and plasma IL-18 were also evaluated. The significant level was determined as p<0.05.
Results: Plasma IL-18 was significantly and negatively related to VO2max (p≤0.02). Also there was a positive significant relationship between IL-18 and BMI (p≤0.001) and WHR (p≤0.031). The dietary composition and lipid profile had no significant correlation with IL-18 and VO2max. The fat and total energy intake was negatively related to plasma HDL. WHR and BMI showed positive significant correlation with fat and total energy intake.
Conclusion: In summary, high VO2max and low BMI and WHR are predictors of low IL-18 and systemic inflammation.