Aim
To explore the association between antibodies against glutamic acid decarboxylase (GADA), a major antigen from beta cells, and indices of whole-body IR and beta-cell capacity/insulin secretion in adults who do not have diabetes.
Background
Autoimmunity against insulin-producing beta cells from pancreatic islets is a common phenomenon in type 1 diabetes and latent autoimmune diabetes in adults. Some reports have also related beta-cell autoimmunity to insulin resistance (IR) in type 2 diabetes. However, the extent to which autoimmunity against components of beta cells is present and relates to IR and insulin secretion in nondiabetic adults is uncertain.
Conclusion
GADA positivity is frequent and likely related to impaired beta-cell function among adults without known diabetes.
Methods
We studied 81 adults of both sexes aged 30-70, without known diabetes or any autoimmune disease. Participants underwent an oral glucose tolerance test (OGTT) with determination of plasma glucose and insulin at 0, 30, 60, 90, and 120 minutes. From these
Results
We found an overall prevalence of GADA positivity of 21.3%, without differences by sex and no correlation with age. GADA titers did not change monotonically across quartiles of any of the IR or insulin secretion indices studies. GADA did not correlate linearly with fasting IR expressed as HOMA-IR (Spearman's r=-0.18, p=0.10) or postabsorptive IR expressed as iAUCins (r=-0.15, p=0.18), but did show a trend toward a negative correlation with insulin secretory capacity expressed by the HOMA-beta cell% index (r=-0.20, p=0.07). Hemoglobin A1c, body mass index, and waist circumference were not associated with GADA titers.