Associations Between Insulin Stimulated Glucose Disposal, Physical Activity, Adiposity, And Fitness In Healthy Adolescents

PURPOSE: We examined the independent roles of physical activity, adiposity, and cardiorespiratory fitness on insulin stimulated glucose disposal in adolescents. METHODS: Thirty-nine healthy adolescents (males = 14, females = 25) were recruited and stratified based on Body Mass Index percentiles (BMI%) based on CDC age and sex-specific norms and objectively measured physical activity for seven days via Actigraph GT9x. Sedentary behavior was collected using the ActivPAL 3. Body composition was assessed using dual energy absorptiometry. Groups were categorized as normal weight-active (NW/Active), normal weight-inactive (NW/Inactive), overweight/obese-active (OWOB/Active), and overweight/obese-inactive (OWOB/Inactive). Insulin stimulated glucose disposal (GD) was assessed during a hyperinsulinemic euglycemic clamp. Cardiorespiratory fitness (CRF) was assessed using a maximal treadmill test using indirect calorimetry (ParvoMedics TrueOne). RESULTS: Descriptive information is provided in the table. There was no significant difference in GD by group during the clamp procedure, adjusted by sex using SAS Proc GLM, (NW/Active group (9.2 ± 1.4 mg/kg/min, NW/Inactive = 6.7 ± 1.5, OWOB/Active = 8.7 ± 1.4, OWOB/Inactive = 5.7 ± 1.4, P = 0.26). When the two active groups were combined, the Active group had higher GD than the Inactive group (8.9 mg/kg/min vs. 6.2 mg/kg/min, P = 0.05). For the entire group, there was no significant association between GD and vector magnitude average counts from the Actigraph GT9x (P = 0.19) or steps/day (P = 0.14) or sedentary time of 2-4 hrs (P = 0.53) from the ActivPAL3 (all adjusted for sex and BMI%). However, cardiorespiratory fitness was associated with GDR (P = 0.012, adjusted for sex and BMIz). CONCLUSIONS: These findings suggest that physically active adolescents, regardless of obesity status, have better glucose disposal compared to inactive adolescents. - Descriptive information BMI% Vector magnitude average counts Cardiorespiratory fitness, per kg of body weight Cardiorespiratory fitness, per kg of fat free mass NW/Active 56%ile 2153 counts 45.0 mL/kg/min 56.8 mL/kgFFM/min OWOB/ Active 92%ile 2118 counts 33.9 mL/kg/min 52.9 mL/kgFFM/min NW/Inactive 42%ile 1408 counts 38.5 mL/kg/min 51.4 mL/kgFFM/min OWOB/Inactive 93%ile 1290 counts 32.0 mL/kg/min 50.1 mL/kgFFM/min NIH 1K01DK119545