Antibodies to glutamic acid decarboxylase as predictors of insulin-dependent diabetes mellitus before clinical onset of disease.
We have done a study designed to ascertain the effectiveness of measuring antibodies to glutamic acid decarboxylase (anti-GAD) in predicting insulin-dependent diabetes mellitus (IDDM). Anti-GAD was measured in prediabetic sera from 151 women aged 20-39 years with newly diagnosed diabetes mellitus who had been identified through a nationwide diabetes register. Multiple serum samples had been collected from these women up to 10 years before the clinical onset of diabetes during their earlier pregnancies. Anti-GAD was measured with a radioimmunoprecipitation assay. Anti-GAD was detected in 82% of 28 women with IDDM, in 36% of 11 women with non-insulin-dependent diabetes mellitus, and in 5% of 112 women with gestational diabetes mellitus. In a random sample of 100 non-diabetic young Finnish women, none had anti-GAD. The sensitivity of the anti-GAD assay for predicting IDDM was 82.1% and the specificity was 100%. The longest time of anti-GAD positivity before clinical onset of IDDM was 10 years. Once positive, anti-GAD levels remained stable and no patients became negative after a positive test during the prediabetic period. Anti-GAD is a valuable early predictive marker and is associated with a very high risk for development of IDDM.
Tuomilehto
J
J
Department of Epidemiology and Health Promotion, National Public Health Institute, Helsinki, Finland.
Zimmet
P
P
Mackay
I R
IR
Koskela
P
P
Vidgren
G
G
Toivanen
L
L
Tuomilehto-Wolf
E
E
Kohtamäki
K
K
Stengård
J
J
Rowley
M J
MJ
D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis* / Q000276:immunology; D003924:Diabetes Mellitus, Type 2 / Q000276:immunology; D016640:Diabetes, Gestational / Q000276:immunology; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D012680:Sensitivity and Specificity
D001323:Autoantibodies; D015415:Biomarkers; D005968:Glutamate Decarboxylase