Antibodies to glutamic acid decarboxylase in young Chinese diabetic patients

SUMMARY. Antibodies to glutamic acid decarboxylase (GAD) are a useful autoimmune marker for type I diabetes mellitus in Caucasians. We examined antibodies to GAD and their relationships with clinical features and pancreatic Pcell function in 140 young Chinese diabetic patients. Over an 18-month period beginning in 1995, 140 young Chinese diabetic subjects with age of onset of disease ~ 35 years and age 18 units) were detected in 12·1% (n=17) of these subjects. Forty-three (31%) patients had a classical type I presentation and 65 (46%) patients were insulin-deficient based on post-glucagon plasma C-peptide levels. Patients who were insulin-deficient and had a type I presentation had the highest prevalence of antibodies to GAD (29'0%) compared with patients who had a type 2 presentation and were non-insulin deficient (6-4%, P = 0'003). Patients who had antibodies to GAD had lower body mass index and waist-hip ratio, earlier onset of disease, lower blood pressure, plasma triglyceride and C-peptide, and higher concentrations of plasma high-density lipoprotein cholesterol and glycated haemoglobin, and were more likely to require drug treatment, compared with those without antibodies to GAD. In conclusion, there was a low prevalence of antibodies to GAD in Chinese young diabetic patients although such antibodies remained a relatively specific marker for insulin deficiency and acute presentation. Causes other than autoimmunity should be sought to explain the high prevalence of insulin deficiency in these young Chinese patients.