The prevalence of the 65-kilodalton isoform of glutamic acid decarboxylase autoantibodies by glucose tolerance status in elderly patients from the cardiovascular health study

J Clin Endocrinol Metab. 2006 Aug;91(8):2871-7. doi: 10.1210/jc.2005-2667. Epub 2006 May 23.


Context: Autoantibodies (AA) to glutamic acid decarboxylase (GAD65), a determinant of risk for autoimmune diabetes, have been found in up to 10% of patients with type 2 diabetes. In older adults, this marker may also serve as a determinant of risk for autoimmune diabetes and enhance diabetes classification.

Objective: The objective of this study was to evaluate the relationship between GAD65AA and glucose tolerance status, current diabetes treatment, and clinical measures in older adults.

Design: GAD65AA were measured at baseline in 3318 participants from the Cardiovascular Health Study, a cohort study of 5888 individuals 65 or older.

Setting: The population-based cohort was recruited from four U.S. sites.

Patients: Patients included all Cardiovascular Health Study participants with known diabetes, newly diagnosed diabetes, impaired fasting glucose, impaired glucose tolerance, and a sample of normal glucose-tolerant participants.

Main outcome measures: GAD65AA, body mass index, fasting glucose and insulin levels, blood pressure, lipid levels, and diabetes treatment at baseline were measured.

Results: The prevalence of GAD65AA increased with decreasing glucose tolerance in both Blacks (n = 560) and Whites (n = 2730), being more pronounced in known diabetic individuals. GAD65AA were found in 2.3, 5.8, 7.8, and 8.3% of diabetic participants, reporting use of no diabetes medication, oral hypoglycemic agents, insulin only, and both oral hypoglycemic agents and insulin, respectively (P = 0.02, linear trend). Among diabetic participants, GAD65AA positivity was associated with diabetes treatment, higher fasting glucose, and lower body mass index.

Conclusions: Even among older individuals with diabetes, GAD65AA may be a useful marker in identifying a subgroup of autoimmune diabetes, serve as a marker of insulin requirement, and remain stable over years.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Aging*
  • Autoantibodies / blood*
  • Blood Glucose / analysis
  • Blood Pressure
  • Cardiovascular Diseases
  • Cohort Studies
  • Diabetes Mellitus, Type 2 / enzymology
  • Diabetes Mellitus, Type 2 / immunology
  • Fasting
  • Female
  • Glucose Intolerance / immunology*
  • Glutamate Decarboxylase / immunology*
  • Humans
  • Insulin / blood
  • Isoenzymes / immunology*
  • Lipids / blood
  • Logistic Models
  • Male
  • Nutrition Surveys


  • Autoantibodies
  • Blood Glucose
  • Insulin
  • Isoenzymes
  • Lipids
  • Glutamate Decarboxylase
  • glutamate decarboxylase 2