title: Pancreatic beta cell function and antibodies to glutamic acid decarboxylase (anti-GAD) in Chinese patients with clinical diagnosis of insulin-dependent diabetes mellitus.
abstract: Antibodies to glutamic acid decarboxylase (anti-GAD) and pancreatic beta cell secretory function were measured in 39 consecutive Chinese patients with a clinical diagnosis of insulin-dependent diabetes mellitus (IDDM) (19 males, mean +/- SD age. 37 +/- 15 years; body mass index (BMI), 22 +/- 4 kg/m2; mean duration of disease, 6.7 +/- 5.6 years). IDDM was defined on the basis of acute symptoms with heavy ketonuria (> 3+) or ketoacidosis at diagnosis, or requirement for continuous insulin treatment within one year of diagnosis. Insulin deficiency was defined as a post-glucagon stimulated plasma C-peptide concentration < or = 0.6 nmol/l. Overall, anti-GAD antibodies were positive (> 18 units) in 23% (n = 9) of these patients. Of the 39 patients, 29 (74%) were insulin deficient and 10 (26%) were non-insulin deficient. Anti-GAD antibodies were positive in 31% of the insulin-deficient patients but in none of the non-insulin-deficient group. Insulin deficiency and anti-GAD positivity were associated with younger age, earlier age of clinical onset and lower BMI. There were independent negative relationships between levels of anti-GAD antibodies and blood pressure and a positive relationship between insulin dosage and albuminuria. This study emphasises the difficulty in differentiating clinically between IDDM and NIDDM in Chinese patients. Despite the acute presentation, these patients had variable pancreatic beta cell secretory function. The varying duration of disease may partly explain the low prevalence of positive anti-GAD antibodies in these patients, but seems unlikely to explain fully the difference from Caucasian IDDM patients.
authors.affiliation: Department of Clinical Pharmacology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong.
authors.forename: J C
authors.initials: JC
authors.lastname: Chan
authors.forename: V T
authors.initials: VT
authors.lastname: Yeung
authors.forename: C C
authors.initials: CC
authors.lastname: Chow
authors.forename: G T
authors.initials: GT
authors.lastname: Ko
authors.forename: I R
authors.initials: IR
authors.lastname: Mackay
authors.forename: M J
authors.initials: MJ
authors.lastname: Rowley
authors.forename: P Z
authors.initials: PZ
authors.lastname: Zimmet
authors.forename: C S
authors.initials: CS
authors.lastname: Cockram
mesh_terms: D000328:Adult; D001315:Australia; D001323:Autoantibodies / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D015992:Body Mass Index; D002096:C-Peptide / Q000097:blood; D002681:China / Q000208:ethnology; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000276:immunology / Q000503:physiopathology*; D016883:Diabetic Ketoacidosis; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006442:Glycated Hemoglobin / Q000032:analysis; D006723:Hong Kong; D006801:Humans; D007328:Insulin / Q000627:therapeutic use; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D012044:Regression Analysis
chemical_list: D001323:Autoantibodies; D001786:Blood Glucose; D002096:C-Peptide; D005968:Glutamate Decarboxylase; D006442:Glycated Hemoglobin; D007328:Insulin