OBJECTIVETo investigate the positive frequency and distribution of glutamic acid decarboxylase antibody(GAD-Ab) in phenotypic type 2 diabetic(T2DM) patients.

METHODSSera of 2035 phenotypic T2DM patients were screened for GAD-Ab with radioligand assay. The positive frequency of GAD-Ab and its relation with clinical features were analyzed.

RESULTS(1) The positivity of GAD-Ab in clinic-based, phenotypic T2DM patients was 7.1% (145/2035), comparable to that of data from Caucasians as shown by UKPDS(8.7% vs. 9.8%, P = 0.391) and ADOPT (8.0% vs. 4.2%, P = 0.000) but higher than that of Japanese in Ehime study(7.1% vs. 3.8%, P = 0.000). (2) The positive frequency and distribution of GAD-Ab titer were related to clinical features, including age at onset, body mass index (BMI) and fasting C peptide levels. Patients with younger age at onset (0.33 vs. 0.11, P < 0.05), less BMI (0.34 vs. 0.10, P < 0.05) and lower C peptide levels (0.38 vs. 0.11, P < 0.05) would have higher GAD-Ab titers.

CONCLUSION(1)The positivity of GAD-Ab in adult-onset phenotypic T2DM in Chinese was similar to that of Caucasians but higher than that of the Japanese. (2) The distribution of GAD-Ab titers was associated with clinical features, with high GAD-Ab titers for those having younger age at onset, less BMI and lower C peptide levels.

Adolescent ; Adult ; Age of Onset ; Aged ; Aged, 80 and over ; Antibodies ; immunology ; metabolism ; Body Mass Index ; Case-Control Studies ; Child ; Child, Preschool ; Diabetes Mellitus, Type 2 ; diagnosis ; metabolism ; pathology ; physiopathology ; Female ; Glutamate Decarboxylase ; immunology ; Humans ; Infant ; Male ; Middle Aged ; Phenotype ; Young Adult