CONTEXT: Insulin sensitivity (SI) varies with age in type 1 diabetes (T1D). OBJECTIVE: To compare postprandial glucose turnover and SI between adolescents and adults with T1D. DESIGN: This cross-sectional comparison at a clinical research unit included 21 early adolescents with T1D (T1D-adol) (12 F
age, 11.5 ± 0.5 years
BMI 19 ± 2 kg/m2), 13 adults with T1D (T1D-adult) (5 F
37.8 ± 9.1 years
BMI 27 ± 2 kg/m2), and 14 anthropometrically matched adults without diabetes (ND) (7 F
26.9 ± 7.0 years
BMI 25 ± 2.5 kg/m2). Using triple tracer mixed meal and oral glucose models, SI in T1D-adol and T1D-adult was compared. RESULTS: Postprandial glucose excursions were not different in T1D-adol vs T1D-adult (P = .111) but higher than in ND (P <
.01). Insulin excursions were also similar in T1D-adol vs T1D-adult (P = .600) and they were both lower (P <
.05) compared to ND, while glucagon excursions were lower (P <
.01) in T1D-adol than in T1D-adult and ND. Integrated rates of endogenous glucose production and glucose disappearance were lower in T1D-adol than in T1D-adult and in ND vs T1D-adult but did not differ between T1D-adol and ND. Meal glucose appearance did not differ between groups. While SI in T1D-adol vs ND was similar (P = .299), it was higher in T1D-adol and ND vs T1D-adult (P <
.01). CONCLUSION: We report differences in parameters of postprandial glucose turnover and insulin sensitivity between adults and early adolescents with T1D that could, at least in part, be due to the shorter duration of diabetes among T1D-adol. These data support the concept that over time with T1D, endogenous glucose production increases and SI deteriorates.