Antibodies against glutamic acid decarboxylase and indices of insulin resistance and insulin secretion in nondiabetic adults: a cross-sectional study

• Published in: Diabetes, metabolic syndrome and obesity Vol. 10; pp. 179 - 185
• Main Authors: Mendivil, Carlos O, Toloza, Freddy Jk, Ricardo-Silgado, Maria L, Morales-Álvarez, Martha C, Mantilla-Rivas, Jose O, Pinzón-Cortés, Jairo A, Lemus, Hernán N
• Format: Journal Article
• Language: English
• Published: New Zealand Dove Medical Press Limited 01.01.2017; Taylor & Francis Ltd; Dove Medical Press
• Subjects: Acids; Analysis; Antibodies; Autoimmune diseases; autoimmunity; beta cell; Cross-sectional studies; Diabetes; Diabetes mellitus; Glucose; Glutamate decarboxylase; Hemoglobin; Immune system; Immunoglobulins; Insulin resistance; Laboratories; Latent Autoimmune Diabetes in Adults; Original Research; Pancreatic beta cells; PCB; Plasma; Polychlorinated biphenyls; Sexes; United States > US; beta cell; latent autoimmune diabetes in adults; autoimmunity; insulin resistance; glutamate decarboxylase
• ISSN: 1178-7007; 1178-7007
• DOI: 10.2147/DMSO.S137216

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. 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. 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 calculated indices of insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR] and incremental area under the insulin curve [iAUCins]) and insulin secretion (corrected insulin response at 30 minutes and HOMA beta-cell%). GADAs were measured in fasting plasma using immunoenzymatic methods. 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 =-0.18, =0.10) or postabsorptive IR expressed as iAUCins ( =-0.15, =0.18), but did show a trend toward a negative correlation with insulin secretory capacity expressed by the HOMA-beta cell% index ( =-0.20, =0.07). Hemoglobin A1c, body mass index, and waist circumference were not associated with GADA titers. GADA positivity is frequent and likely related to impaired beta-cell function among adults without known diabetes.