Optimal Cut-off Points of Fasting and Post-Glucose Stimulus Surrogates of Insulin Resistance as Predictors of Metabolic Syndrome in Adolescents According to Several Definitions

OBJECTIVE: The aim of this study was to determine optimal cut-off points for fasting and post-glucose stimulus surrogates of insulin resistance to predict metabolic syndrome in adolescents according to several definitions. METHODS: One hundred fifty-five adolescents living in Mexico City were enrolled during 2011 and 2012. Waist circumference and blood pressure were recorded. Subjects received an oral glucose load of 1.75 g per kg up to a maximum dose of 75 g. Blood samples were drawn at baseline and 120 minutes. Concentrations of plasma glucose, triglycerides, high-density lipoprotein cholesterol and insulin were determined. RESULTS: The frequency of metabolic syndrome showed a large variability when using a variety of published definitions; in contrast, the optimal cut-off points for fasting insulin, homeostatic model assessment of insulin resistance and two-hour oral glucose tolerance test insulin were very similar in almost all the definitions considered and had adequate diagnostic performance: area under the curve >0.869, sensitivity >0.835 and specificity >0.755. Insulin resistance surrogates had substantial agreements with Ford, Cook and Salas definitions (Kappa~0.62; agreement~82%); moderate agreement was observed for International Diabetes Federation, Cruz and Ferranti definitions (Kappa~0.41­0.59; agreement~77%). CONCLUSION: Insulin resistance surrogates may be a better approach for metabolic syndrome assessment in an adolescent population because of reduced variability and a higher predictive value.

The 13C-Glucose Breath Test for Insulin Resistance Assessment in Adolescents: Comparison with Fasting and Post-Glucose Stimulus Surrogate Markers of Insulin Resistance.

OBJECTIVE: To evaluate the use of the 13C-glucose breath test (13C-GBT) for insulin resistance (IR) detection in adolescents through comparison with fasting and post-glucose stimulus surrogates. METHODS: One hundred thirty-three adolescents aged between 10 and 16 years received an oral glucose load of 1.75 g per kg of body weight dissolved in 150 mL of water followed by an oral dose of 1.5 mg/kg of U-13C-Glucose, without a specific maximum dose. Blood samples were drawn at baseline and 120 minutes, while breath samples were obtained at baseline and at 30, 60, 90, 120, 150, and 180 minutes. The 13C-GBT was compared to homeostasis model assessment (HOMA) IR (≥p95 adjusted by gender and age), fasting plasma insulin (≥p90 adjusted by gender and Tanner stage), results of 2-h oral glucose tolerance test (OGTT), insulin levels (≥65 µU/mL) in order to determine the optimal cut-off point for IR diagnosis. RESULTS: 13C-GBT data, expressed as adjusted cumulative percentage of oxidized dose (A% OD), correlated inversely with fasting and post-load IR surrogates. Sexual development alters A% OD results, therefore individuals were stratified into pubescent and post-pubescent. The optimal cut-off point for the 13C-GBT in pubescent individuals was 16.3% (sensitivity=82.8% & specificity=60.6%) and 13.0% in post-pubescents (sensitivity=87.5% & specificity=63.6%), when compared to fasting plasma insulin. Similar results were observed against HOMA and 2-h OGTT insulin. CONCLUSION: The 13C-GBT is a practical and non-invasive method to screen for IR in adolescents with reasonable sensitivity and specificity.

[Emerging and reemerging diseases]. / Enfermedades emergentes y reemergentes.

Emerging and reemerging diseases are the result of the interaction of multiple factors, such as social determinants of health, climate change, and conditions that prevail and are identifiable in some populations. As a consequence, there may be situations that by their nature are defined as a health emergency, impacting directly on the health of a population, either because they are not known or due to their rapid spread, resulting in a health security problem. Examples of these diseases are described in this article, starting with their origin, their impact on the population, and the response necessary in order to contain or prevent damage of a greater magnitude. The presence of these agents and their consequent damage to the population should lead efforts towards comprehensive prevention and appropriate containment strategies to ensure the protection of public health. Endeavors should be directed not only to a specific agent, but rather to factors that determine their reemergence, such as Ebola, or their permanence, such as the binomial infection of tuberculosis-AIDS. In order to correctly implement strategies, training and availability of supplies play a crucial role in facing the challenges that lie ahead.

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 13C-glucose breath test (13C-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 13C-glucose/kg dissolved in water, breath samples were taken at baseline, 30, 60, 90, 120, 150 and 180 min. Exhaled 13CO2 in breath samples was measured by isotope ratio mass spectrometry. RESULTS: 13C-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 13C-glucose breath test could be a valid screening method to identify MS in adolescents.