The 13C-glucose breath test is a valid non-invasive screening tool to identify metabolic syndrome in adolescents

Background: Metabolic syndrome (MS) is an important risk factor in pediatric population for the early onset of type 2 diabetes mellitus and cardiovascular disease. New non-invasive tools are required to identify MS in at risk populations; the aim of this study was to determine an optimal cut-off point for the C-13-glucose breath test (C-13-GBT) for the diagnosis of MS in adolescents. Methods: A total of 136 adolescents between 10 and 16 years old were recruited. MS was defined as: waist circumference >90th percentile and at least two of the following; high density lipoprotein-cholesterol (HDL-C) <50 mg/dL, triglycerides >110 mg/dL, diastolic and/or systolic blood pressure >90th percentile adjusted by age, gender and height, and/or fasting glucose > 100 mg/dL. After the ingestion of a glucose load of 1.75 g/kg of body weight (up to 75 g) and an oral dose of 1.5 mg of universally labeled C-13-glucose/kg dissolved in water, breath samples were taken at baseline, 30, 60, 90, 120, 150 and 180 min. Exhaled (CO2)-C-13 in breath samples was measured by isotope ratio mass spectrometry. Results: C-13-GBT data, expressed as adjusted cumulative percentage of oxidized dose (A% OD) at 180 min, was significantly higher in the healthy subjects group (17.72%+/- 4.9%) in comparison with subjects with >= 3, 2 or 1 components of the MS (9.95%+/- 4.73%, 14.3%+/- 4.47% and 14.62%+/- 4.62%, respectively). The optimal cut-off point for the A% OD was 16.09, with a sensitivity of 81.5% and a specificity of 66.7%. Conclusions: Our results demonstrate that the C-13-glucose breath test could be a valid screening method to identify MS in adolescents.