13C/12C breath test ratio after the ingestion of a meal naturally enriched with (13C)carbohydrates is a surrogate marker of insulin resistance and insulin sensitivity in children and adolescents with Type 1 Diabetes

AIMS: To test the hypotheses that exogenous carbohydrate oxidation affects postprandial glycaemic profiles and 13C/12C breath test could be used for estimating insulin resistance (IR) and insulin sensitivity (IS) in youths with Type 1 Diabetes (T1D).METHODS: Non-randomized, cross-sectional study for repeated measures; fifteen youths (11-15years) with T1D were enrolled. Respiratory exchanges were measured by indirect calorimetry after the ingestion of a mixed meal [13% protein, 29% fat, 58% carbohydrate (CHO; naturally enriched with [13C]carbohydrates)]. Total and exogenous CHOs oxidation was calculated by indirect calorimetry and 13C/12C breath test. IR and IS were calculated using estimated Glucose Disposal Rate (eGDR) and Insulin Sensitivity Score (ISS).RESULTS: The blood glucose Area Under the Curve (BG-AUC) was significantly associated with the amount of exogenous CHOs oxidized (r=-0.67, p<0.02) when adjusting for CHOs intake and út mass. A direct correlation between eGDR and ISS with exogenous CHOs oxidized (r=0.70, p<0.02; r=0.61, p<0.05 respectively) and with the differential of 13C/12C enrichment in the expired at breath test (r=0.59, p<0.05; r=0.62, p<0.05), was found.CONCLUSIONS: Assessing the capacity to oxidize exogenous CHOs (estimated by the differential of 13C/12C enrichment in the expired air at the breath test) could be used as a non-invasive surrogate marker of IR and IS in youths with T1D.