Islet cell autoimmunity in a triethnic adult population of the Third National Health and Nutrition Examination Survey.
Markers of humoral islet cell autoimmunity, such as autoantibodies (AAs) against the 65-kDa isoform of GAD (GAD65), serve as determinants of risk for autoimmune diabetes. Despite the high prevalence of diabetes in U.S. racial and ethnic minority adult populations, little is known concerning the prevalence of GAD65 AA in these groups. We estimated the prevalence of GAD65 AA in 1,064 diabetic and 1,036 nondiabetic participants who were 40-90 years of age from the Third National Health and Nutrition Examination Survey (NHANES III), which provides a representative ethnic sample of the U.S. diabetic population. The prevalence of GAD65 AA was higher in diabetic participants compared with nondiabetic participants in non-Hispanic whites (n = 920; 6.3% vs. 2.0%; P = 0.001) and non-Hispanic blacks (n = 534; 3.7% vs. 1.3%; P = 0.08) but not in Mexican Americans (n = 646; 1.2% vs. 2.6%; P = 0.18). Among diabetic non-Hispanic whites and non-Hispanic blacks, being GAD65 AA positive was associated with lower BMI and C-peptide (P < 0.05). These results may reflect the outcome of an autoimmune process leading to beta-cell destruction/dysfunction in non-Hispanic white and non-Hispanic black adult diabetic patients as it occurs in a similar manner in type 1 diabetes. Among diabetic Mexican Americans, the lower prevalence of GAD65 AA suggests a lower frequency of autoimmune-related diabetes.
Barinas-Mitchell
Emma
E
Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, 130 DeSoto Street, Pittsburgh, PA 15261, USA. barinas@edc.pitt.edu
Pietropaolo
Susan
S
Zhang
Ying-Jian
YJ
Henderson
Tyona
T
Trucco
Massimo
M
Kuller
Lewis H
LH
Pietropaolo
Massimo
M
D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000032:analysis; D015551:Autoimmunity; D044383:Black People / Q000706:statistics & numerical data; D016022:Case-Control Studies; D003920:Diabetes Mellitus / Q000208:ethnology* / Q000276:immunology*; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology; D006801:Humans; D007515:Islets of Langerhans / Q000276:immunology*; D007527:Isoenzymes / Q000276:immunology; D008297:Male; D017058:Mexican Americans / Q000706:statistics & numerical data; D008875:Middle Aged; D009749:Nutrition Surveys; D044465:White People / Q000706:statistics & numerical data
D001323:Autoantibodies; D007527:Isoenzymes; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2