Prevalence of prediabetes in children and adolescents by class of obesity

Background: To evaluate prevalence of prediabetes (impaired fasting glucose, IFG; impaired glucose tolerance, IGT; and high glycated haemoglobin, h-HbA1c) in children and adolescents in relation to class of age and obesity; to appraise association with estimates of insulin metabolism, cardiovascular risk factors and alanine aminotransferase (ALT) levels. Methods: Study of marginal prevalence (i.e., as function of sex, age and obesity class) of isolated and combined IFG, IGT and h-HbA1c in children (age 4-9.9 years) and adolescents (age 10-17.9 years) and association to blood pressure (BP), total, HDL and non-HDL cholesterol, triglycerides, ALT and insulin sensitivity/secretion indexes. Results: Data of 3110 participants (51% males, 33% children; 33% overweight, 39% obesity class I, 20.5% class II, 7.5% class III) were available. Unadjusted prevalence of prediabetes was 13.9% in children (2.1% IFG, 6.7% IGT, 3.9% h-HbA1c, IFG-IGT 0.06%) and 24.6% in adolescents (3.4% IFG, 9.4% IGT, 5.5% h-HbA1c, IFG-IGT 0.09%). Combined h-HBA1c was found in very few adolescents. Prevalence of prediabetes increased significantly by class of obesity up to 20.5% in children and 31.6% in adolescents. Phenotypes of prediabetes were differently but significantly associated with increased systolic and diastolic BP (by 2-7.3 and ~8 mmHg, respectively), triglycerides (by 23-66 mg/dl), and ALT levels (by 10-22 UI/L) depending on the prediabetes phenotype. Conclusion and relevance: It is worth screening prediabetes in children aged <10 years old with obesity classes II and III and in adolescents. In those with prediabetes, monitoring of blood pressure, triglycerides and ALT levels must be encouraged.