The association between pentraxin 3 and insulin resistance in obese children at baseline and after physical activity intervention

Background: The role of pentraxin-3 (PTX3) in the development of insulin resistance is still not clear. We aimed to test 1) whether circulating PTX3 levels are associated with insulin resistance and 2) whether changes in PTX3 levels after the physical activity are associated with changes in insulin resistance. Methods: Fifty-seven overweight or obese children (39 boys, 18 girls; age: 12.04±0.82y, BMI: 26.5±1.2kg/m ² ) participated in the study. All participants were housed together and their amount of physical activity (1823.5±1.34kcal/day) and food intake (1882±68.8kcal/day) were tightly controlled. Results: Circulating PTX3 levels at baseline were negatively associated with fasting insulin (r=-.336, p=0.012) and homeostasis model assessment of insulin resistance (HOMA-IR) (r=-.334, p=0.014) even after adjustment for BMI and Tanner stage. The degree of change in PTX3 levels notably associated with changes in fasting insulin (r=-.280, p=0.035) and HOMA-IR (r=-.281, p=.034) in response to the physical activity intervention. Subgroup analysis further indicates that HOMA-IR was improved more in subjects whose PTX3 levels were increased compared with subjects who PTX3 levels were decreased (HOMA-IR delta: -2.33 ± 1.3 vs -1.46 ± 0.70, p=0.004). Conclusion: PTX3 is negatively associated with insulin resistance and associated with changes in insulin resistance induced by physical activity in overweight and obese children.