Type 1 diabetes-related autoantibodies are rare in Alaska native populations

Abstract

Objectives. When clinical data were initially gathered from the Alaskan Eskimos in the 1950’s, diabetes mellitus was noted to be quite rare. The prevalence of diabetes has increased significantly since that time, with rates of 10% reported recently in some Alaska native populations. Our goal was to understand the pathogenesis of diabetes among these groups, with the hypothesis that Alaskan Eskimos were predominantly affected by type 2 diabetes, not by latent autoimmune diabetes in adults (LADA).

Study design. Population based case control study

Methods. We tested sera from subjects in two Eskimo villages for the presence of type 1 diabetes-related autoantibodies against glutamic acid decarboxylase (GAD65Ab) and tyrosine phosphatase-like islet antigen-2 (IA-2Ab). Results. Among subjects from one Inupiat village (#1) and one SiberianYup’ik village (#2), there were 21 subjects with diabetes mellitus (DM), 17 with impaired glucose tolerance (IGT), and 226 healthy controls with normal glucose tolerance (NGT). In village 1, GAD65 antibodies were not present in either diabetic subjects or those with IGT. One of the healthy controls (1%;1/97) was positive for GAD65Ab. Similarly, no subjects from this village with DM or IGT had positive IA-2Ab titers, and one healthy control (1%;1/97) was positive for IA-2Ab. In village 2, no DM subject was GAD65Ab positive. One (10%;1/10) of the IGT subjects and two (1.6%;2/129) of the healthy controls were positive for GAD65Ab. In this village, two of the DM subjects (12%;2/17), one of the IGT subjects (10%;1/10), and one of the healthy controls (0.8%;1/129) were IA-2Ab positive. No individual was positive for both GAD65Ab and IA-2Ab. Conclusion. Alaskan Inupiat and Siberian Yup’ik Eskimos appear to be predominantly affected by type 2 diabetes, not LADA.

Key Words:

• diabetes mellitus
• latent autoimmune diabetes of the adult (LADA)
• glutamic acid decarboxylase (GAD)
• tyrosine phosphatase-like is-let antigen-2 (IA-2)
• autoantibodies
• Eskimos

Additional information

Notes on contributors

Lisa K. Gilliam

Dr. Lisa K. Giliam, Robert H Williams Laboratory, University of Washington, Seattle, WA