Association between insulin resistance and GAD65-autoantibody levels--a pilot study in an adult non-diabetic population.

The aim of this pilot study was to investigate any association between insulin resistance (IR) and serum levels of autoantibodies against the glutamic acid decarboxylase (GAD65Ab) among adult non-diabetic subjects. Based on calculations of IR using the IR homeostasis model in a Swedish adult non-diabetic population (n = 756) participating in the WHO MONICA-study, an insulin sensitive group (n = 54, M/F:27/27) and an insulin resistant group (n = 46 M/F:24/22) were identified. Serum from the subjects were analysed for the presence of GAD65Ab. There was no significant difference in GAD65Ab levels between the groups. However, there was a correlation between IR and serum GAD65Ab within the insulin sensitive group (Spearman rho 0.4, p < 0.01). Our observation could indicate that IR could serve as an initiator or a progression factor in the autoimmune process in subjects predisposed to autoimmunity. This finding will be further investigated in a larger study including subjects with a continuum of IR.