Oral glucose tolerance test in children and adolescents: positives and pitfalls.
OBJECTIVE
To describe the glycaemic status (assessed by an oral glucose tolerance test (OGTT)) and associated comorbidities in a cohort of Australian children and adolescents at risk of insulin resistance and impaired glucose homeostasis (IGH).


METHODS
Twenty-one children and adolescents (three male, 18 female) (18 Caucasian, one Indigenous, two Asian) (20 obese, one lipodystrophy) referred to the Paediatric Endocrinology and Diabetes Clinic underwent a 2-h OGTT with plasma glucose and insulin measured at baseline, + 60 and + 120 min. If abnormal, the OGTT was repeated.


RESULTS
The mean (SD) age was 14.2 (1.6) years, BMI 38.8 (7.0) kg/m2 and BMI-SDS 3.6 (0.6). Fourteen patients had fasting insulin levels >21 mU/L. Type 2 diabetes mellitus was diagnosed in one patient, impaired glucose tolerance (IGT) in four patients and impaired fasting glycaemia (IFG) in one patient. Despite no weight loss, only one patient had a persistently abnormal OGTT on repeat testing. Three patients with IGH were medicated with risperidone at the time of the initial OGTT. One patient who had persistent IGT had continued risperidone. The other two patients had initial OGTT results of IGT and diabetes mellitus type 2. They both ceased risperidone between tests and repeat OGTT showed normal glycaemic status.


CONCLUSIONS
Use of fasting glucose alone may miss cases of IGH. Diagnosis of IGT should not be made on one test alone. Interpretation of glucose and insulin responses in young people is limited by lack of normative data. Larger studies are needed to generate Australian screening recommendations. Further assessment of the potential adverse effects of atypical antipsychotic medication on glucose homeostasis in this at-risk group is important.
Department of Endocrinology and Diabetes, Royal Children's Hospital, Brisbane, Queensland, Australia. louise_conwell@health.qld.gov.au
L S
LS
Conwell
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JA
Batch
D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D044882:Glucose Metabolism Disorders / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D005951:Glucose Tolerance Test / Q000379:methods; D038321:Glycemic Index; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D008297:Male; D009765:Obesity / Q000097:blood / Q000150:complications*; D011793:Queensland; D012307:Risk Factors
D001786:Blood Glucose; D007328:Insulin