Prevalence of glutamic acid decarboxylase antibodies amongst young Malaysian diabetics

This study determined the prevalence of glutamic acid decarboxylase antibodies (GAD Ab) in a group of 926 young Malaysian diabetics of three ethnic groups, Malay, Chinese, and Indian. Patients were clinically diagnosed to be Type I or Type 2 before the age of 40 years. The overall GAD Ab positivity was 17.4% (161/926), signihcantly higher in the Type 1 than the Type 2 diabetics (35.5%, 1161329 vs. 7.5%,, 451597, P = 0.0001). Compared to GAD Ab negative patients, seropositive diabetics were diagnosed at younger age (21.2 f 0.9 vs. 27.4 + 0.3 y, P = 0.0001), had lower fasting (289 + 27.4 vs. 640 + 17.6 pmol/l, P = 0.0001) and post-glucagon C-peptide levels (527 + 51.8 vs. 1030 + 28.9 pmol/l, P = 0.0001). There were no racial differences in the prevalence of GAD Ab; of the total Type 1, 30.8. 36.4. and 39.4% were Malay, Chinese, and Indian diabetics, respectively and of the total Type 2, 8.8, 8.2. and 4.40,:) were Malay, Chinese, and Indian diabetics respectively. There was a curvilinear relationshi:, between GAD Ab and the post-glucagon C-peptide levels, suggesting that GAD Ab do play a role in the 8-cells'destruction and could be an important immune marker for the LADA group. This study reconfirmed previous reports that the autoimmune mechanisms in the Type 1 Asian diabetics are indeed different from the Caucasians, and further investigations should be carried out to explain the differences. O 1999 Elsevier Science Ireland Ltd. A11 rights reserved.