Search

AIMS: One‐hour post‐load hyperglycaemia has been proposed as an independent predictor of type 2 diabetes in adults. We examined whether 1‐hour plasma glucose (1hPG) during an oral glucose tolerance test (OGTT) can predict changes in the glucose tolerance status of a multi‐ethnic cohort of youths with normal glucose tolerance (NGT). Materials and methods: A total of 202 obese youths with NGT (33.7% Caucasian, 31.1% Hispanic, 32.2% African American) underwent a 3‐hour OGTT at baseline and after a 2‐year follow‐up period. Whole‐body insulin sensitivity, insulin secretion, β‐cell function and insulin clearance were estimated by modeling plasma glucose, insulin and C‐peptide levels. Results: Obese youths with 1hPG ≥7.4 mmol/L (or 133 mg/dL; n = 83) exhibited higher body mass index (BMI), plasma triglycerides and fasting and post‐load glucose concentrations than individuals with 1hPG <7.4 mmol/L. Also, 1hPG ≥7.4 mmol/L was associated with a lower disposition index (DI) (P < 0.0001) and with alterations in whole‐body insulin sensitivity, β‐cell function and insulin clearance. Adolescents with 1hPG ≥7.4 mmol/L were approximately three times more likely to develop prediabetes (ie, impaired glucose tolerance and/or impaired fasting glucose) over time (OR, 2.92 [1.22‐6.98]; P = 0.02), independent of age, sex, race/ethnicity, BMI, insulin sensitivity, DI and plasma glucose concentrations. No differences emerged in the risk of prediabetes related to 1‐hour hyperglycaemia among different ethnic groups. Conclusions: A plasma glucose concentration ≥ 7.4 mmol/L at 1 hour during an OGTT is associated with a worse clinical and metabolic phenotype and may be an independent predictor of progression to prediabetes in obese youths with NGT. [ABSTRACT FROM AUTHOR]

Excess insulin secretion and hyperinsulinaemia contribute to the progression of type 2 diabetes. However, the mechanisms leading to insulin hypersecretion remain largely unknown. Based on our preliminary data, we examined whether triglycerides and very low‐density lipoprotein (VLDL) are independently associated with insulin secretion, and whether ethnicity/race modulates these associations. Fasting triglycerides and VLDL were measured in a multiethnic cohort of 630 non‐diabetic adolescents. Insulin secretion, β‐cell function parameters, insulin sensitivity and insulin clearance were estimated through a 3‐h oral glucose tolerance test. Metabolic assessments were repeated after 2 years in 239 subjects. Triglycerides and triglyceride‐rich VLDL (large and medium size fractions) were associated with both basal and glucose‐stimulated insulin secretion, after adjustment for age, sex, ethnicity, BMI z‐score, plasma glucose, and insulin sensitivity. Ethnicity per se had an impact on lipid profile and β‐cell function, but did not modulate the effect of triglycerides/VLDL on insulin secretion. At follow‐up, changes in triglyceride levels were proportional to changes in insulin secretion. These findings support the hypothesis that hypertriglyceridaemia is an important stimulus for β‐cell insulin release in young people under both fasting and fed conditions. [ABSTRACT FROM AUTHOR]