Impact of Physical Fitness and Glycemic Control on In Vivo Insulin Action in Adolescents With IDDM

Abstract

The relationship of in vivo insulin-mediated glucose utilization to the state of physical fitness and the degree of glycemic control was examined in 27 adolescents with insulin-dependent diabetes mellitus (IDDM) compared with 10 nondiabetic adolescent control subjects. In vivo total-body insulin-mediated glucose metabolism was evaluated by the hyperinsulinemic-euglycemic clamp. Physical fitness was assessed by maximal oxygen consumption (VO2 max) during cycle ergometry. Patients and control subjects had similar levels of VO2 max (34.9 +/- 8.6 vs. 38.6 +/- 9.9 ml.kg-1.min-1, P = 0.3). Patients had lower total-body insulin-mediated glucose metabolism compared with control subjects (33.9 +/- 14.3 vs. 63.8 +/- 17.2 mumol.kg-1.min-1, P = 0.0002). Among the patients, females had lower total-body insulin-mediated glucose metabolism compared with males (24.2 +/- 2.8 vs. 40.7 +/- 3.4 mumol.kg-1.min-1, P less than 0.001); however, this difference disappeared after correcting for sex differences in fitness levels. Insulin-mediated glucose metabolism correlated with VO2 max in patients and control subjects (r = 0.83, r = 0.81, P less than 0.05). The regression of total-body insulin-mediated glucose metabolism on VO2 max for patients was -2.84 +/- 0.255 VO2 max and for control subjects was 7.12 +/- 0.143 VO2 max, indicating that for similar degrees of physical fitness patients have lower total body insulin-mediated glucose metabolism levels than control subjects. In patients, total-body insulin-mediated glucose metabolism correlated with the degree of glycemic control as assessed by the level of glycosylated hemoglobin (r = -0.63, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)