Cardiovascular fitness, insulin resistance and metabolic syndrome in severely obese prepubertal Italian children

Aim: To evaluate if insulin resistance (IR) and metabolic syndrome (MS) were associated with poor cardiovascular fitness in very obese prepubertal Italian subjects. Methods: Children referred to the Endocrinology and Diabetes Unit of Bambino Gesù Children's Hospital underwent an OGTT with glucose and insulin assays. QUICKI, ISI and HOMA-IR were calculated. Total and HDL cholesterol, triglycerides and percentage of body fat (DEXA) were determined. Cardiovascular fitness (maximal treadmill time) was evaluated using a treadmill protocol. The MS was defined as having 3 or more of following risk factors: obesity, impaired glucose tolerance, high blood pressure, low HDL-cholesterol, high triglycerides. Results: Fifty-five very obese prepubertal Italian children were enrolled in the study. Unadjusted correlation revealed maximal treadmill time negatively related to fasting insulin (r = -0.53, p < 0.0001) and HOMA-IR (r = -0.57, p < 0.0001) and positively to QUICKI (r = 0.51, p < 0.0001) and ISI (r = 0.46, p = 0.0035). These relationships remained significant when in multivariate analysis age, gender, BMI SD and body composition were accounted for (all p < 0.01). The presence of the MS was independently associated with maximal treadmill time. Conclusion: Poorcardiovascular fitness, IR and MS were independently related, suggesting that the relationship between fitness and insulin action develops early in life.