Endocrine Abstracts

Background: With the increasing prevalence of obesity and related morbidity including glucose intolerance in childhood, there remains a dispute about the best screening test to identify this early. The aim of our study was to determine the prevalence of impaired glucose tolerance (IGT)/type 2 diabetes mellitus (T2DM) in a multiethnic cohort of 100 overweight/obese children and adolescents in our clinic and compare the results of the screening tests.

Study: Over a 4-year period from 2006 to 2010, 100 overweight/obese children (UK 1990 BMI reference curves used) underwent screening for glucose intolerance using standardised WHO oral glucose tolerance test (OGTT), fasting insulin and HbA1c. Insulin resistance (IR) was defined using HOMA-IR index (>3 as cut-off).

Results: 92% were obese and 8% overweight. 43% were of South Asian (SA) ethnicity, 55% White Caucasian (WC) and 2% other. 61% were females. Mean age was 12.9 years (range 2.5–18.1 years). Nine had IGT and one T2DM (SA) with the remaining 90% having normal OGTT. The prevalence of IGT was higher within SA group (14% in SA vs 5% in WC). All the children with IGT/T2DM had significantly higher HOMA-IR compared to normal OGTT (median: 8.21 (3.6–17.8) v 4.5 (0.5–22.2) but only 5/10 had HbA1c > 6%. Of the 90 with normal OGTT (n=4 with no insulin data), 55/86 (64%) had evidence of IR -median HOMA-IR 6.2 (3–22.2) with 10/55 also having HbA1c > 6%. Of the 31/86 (36%) with normal OGTT and no IR (median HOMA-IR 2.0 (0.5–2.9)), only 1 had HbA1c > 6%. Only 5/100 had all three tests positive.

Conclusion: The prevalence of IGT/T2DM in multiethnic obese/overweight children is high and similar to previously reported studies. 65% of the screened population showed evidence of significant IR. The combination of OGTT with fasting insulin was found to be the best screening test.