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.

Objective To evaluate the usefulness of serial determinations of asymmetric dimethylarginine (ADMA) and homocysteine (Hcy) concentrations during pregnancy to predict pre-eclampsia, taking into account maternal obesity and B vitamin status.Design Longitudinal study.Setting Two obstetric referral hospitals.Sample Two hundred and fifty-two of 411 women invited to participate in the study. MethodsThe women made monthly visits from ≤20 weeks of gestation until delivery for measurements of plasma ADMA, Hcy, and vitamins B 6 , B 12, and folic acid, and for the recording of clinical information.Main outcome measure Early elevations in plasma ADMA and Hcy related to the development of pre-eclampsia.Results Of the 252 women who completed the study, 179 had no complications, 49 developed pre-eclampsia, and 24 presented with complications other than pre-eclampsia. ADMA and Hcy increased gradually throughout pregnancy in the pre-eclampsia group, independent of maternal B-vitamin status and obesity, but remained constant in women with no complications. Relative to the preceding month, ADMA and Hcy levels increased 1 month prior to the onset of pre-eclampsia: 124 AE 27 nmol (P < 0.001) and 1177 AE 278 nmol (P = 0.001), respectively, in the preeclampsia group. The group of women with no complications did not show any significant changes. Increases of 80 nmol ADMA and 1000 nmol Hcy at 1 month prior to the onset of preeclampsia demonstrated the best potential for prediction.Conclusions Increased ADMA and Hcy levels precede clinical manifestations of pre-eclampsia. Therefore, serial determinations of their concentrations may be helpful in identifying women at risk.Keywords ADMA, B vitamins, biomarkers, endothelial damage, homocysteine, pre-eclampsia.Tweetable abstract Increased ADMA and Hcy precede clinical pre-eclampsia and may identify women at risk.Please cite this paper as: L opez-Alarc on M, Montalvo-Velarde I, Vital-Reyes VS, Hinojosa-Cruz JC, Leaños-Miranda A, Mart ınez-Basila A. Serial determinations of asymmetric dimethylarginine and homocysteine during pregnancy to predict pre-eclampsia: a longitudinal study . BJOG 2015;122: 1586-1592

Our results demonstrate that the 13C-glucose breath test could be a valid screening method to identify MS in adolescents.

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~0.41–0.59; agreement~77%).Conclusions: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.