Prevalence of Type 1 Diabetes Autoantibodies (GADA, IA2, and IAA) in Overweight and Obese Children

OBJECTIVE

Little is known about the prevalence of β-cell autoantibodies in children with excess body weight. The prevalence of type 1 diabetes autoantibodies and its relation with hyperglycemia was analyzed in 686 overweight/obese children and adolescents.

RESEARCH DESIGN AND METHODS

All children underwent an oral glucose tolerance test, and anti-GAD, anti-IA2, and anti-IAA autoantibodies were measured. Autoantibody prevalence was evaluated in 107 normal-weight children for comparison.

RESULTS

A single autoantibody was present in 2.18% of overweight/obese subjects and 1.86% normal-weight subjects (P = NS). Postload glycemia was significantly higher in antibody-positive children (133 ± 69.9 vs. 105.4 ± 17.7 mg/dl, P < 0.0001) compared with autoantibody-negative subjects. No difference in autoantibody distribution was seen when our cohort was stratified by age, sex, SDS-BMI, pubertal stage, and homeostasis model assessment–insulin resistance (HOMA-IR).

CONCLUSIONS

The 2.18% prevalence of type 1 diabetes autoantibodies is similar to that reported in nonobese children. This study provided evidence that excess body weight and insulin resistance do not influence autoantibody frequency.Over the last 60 years, a striking increase in the incidence of childhood type 1 diabetes has been observed consistently in almost all populations. EURODIAB (1) reported an overall increase of 3.2% per annum in Europe between 1989 and 1998. There have also been considerable changes in childhood nutrition, which have resulted in changes in growth. Increased weight, height, and BMI in children have all been associated with a higher risk of type 1 diabetes (2). The so-called “accelerator hypothesis” argues that obesity causing overworked β-cells underlies both type 1 and type 2 diabetes and that these “types” are only distinguished by how the body responds to this growth-induced β-cell stress. This hypothesis therefore attributes the rise in type 1 diabetes to an increase in child obesity (3). A variation of the hypothesis suggests that, once initiated, islet autoimmunity progresses more rapidly in the context of “overload” of the β-cells due to increased insulin resistance (4).Sardinia has one of the highest incidences of type 1 diabetes worldwide, second only to Finland (5). Moreover, Sardinian children and adolescents are experiencing the same increase in obesity as other European populations (6). To date, little is known on the prevalence of autoantibodies against β-cells in children with excess body weight.The aim of our study was to analyze the prevalence of type 1 diabetes autoantibodies in a cohort of Sardinian overweight/obese children and adolescents and to evaluate their distribution in relation to the presence of glucose abnormalities.