title: Glutamic acid decarboxylase and islet antigen 2 antibody profiles in people with adult-onset diabetes mellitus: a comparison between mixed ethnic populations in Singapore and Germany.
abstract: To gain insight into the presence of islet cell autoimmunity in an ethnic Asian compared with a white European population.
  
  
  
  For this cross-sectional study we recruited people with adult-onset diabetes (age of diagnosis 20-60 years), at tertiary referral centres in Germany (n=1020) and Singapore (n=1088). Glutamic acid decarboxylase and islet antigen 2 antibodies were measured according to Islet Autoantibody Standardization Program protocols.
  
  
  
  The prevalence of glutamic acid decarboxylase antibody positivity was 13.9% (95% CI 12.1-16.0; P<0.001) in the white European cohort compared with 6.8% (95% CI 5.5-8.4; P<0.001) in the Asian cohort. Glutamic acid decarboxylase antibody positivity was 11.4% (95% CI 7.7-16.6) in Indian, 6.0% (95% CI 3.6-9.9) in Malay and 5.8% (95% CI 4.3-7.7; P<0.001) in Chinese participants. In the white European participants, the prevalence of islet antigen 2 antibody positivity was 7.8% (95% CI 6.4-9.4) compared with 14.8% (95% CI 12.8-17.0; P<0.001) in the Asian cohort as a whole, and among the three ethnicities in the Asian cohort it was 12.4% (95% CI 8.6-17.7) in Indian, 16.8% (95% CI 12.6-22.2) in Malay and 15.7% (95% CI 13.2-18.6) in Chinese participants. Double antibody positivity was seen in 5.7% (95% CI 4.5-7.1) of white European participants compared with 1.6% (95% CI 1.0-2.5; P<0.01) of Asian participants. In the white European cohort, those who were glutamic acid decarboxylase autoantibody-positive had a lower BMI than those who were autoantibody-negative, but this trend was absent in the Asian cohort.
  
  
  
  A marked prevalence of islet cell autoimmunity was observed in people with adult-onset diabetes. While glutamic acid decarboxylase antibodies were more frequent in the European cohort, islet antigen 2 antibody positivity was highest in the three ethnic groups in Singapore, suggesting ethnic-specific differences in antibody profiles.
authors.affiliation: Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore.
authors.forename: Y H
authors.initials: YH
authors.lastname: Ong
authors.affiliation: Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore.
authors.forename: W C A
authors.initials: WCA
authors.lastname: Koh
authors.affiliation: Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore.
authors.forename: M L
authors.identifier: 0000-0003-1859-8592
authors.initials: ML
authors.lastname: Ng
authors.affiliation: Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Tam
authors.affiliation: Clinical Research Unit, Diabetes Centre, Khoo Teck Puat Hospital, Singapore.
authors.forename: S C
authors.initials: SC
authors.lastname: Lim
authors.affiliation: Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore.|Department of Endocrinology, Tan Tock Seng Hospital, Singapore.|Imperial College London, London, UK.|Department of Internal Medicine 1, Ulm University Medical Centre, Ulm, Germany.
authors.forename: B O
authors.identifier: 0000-0002-2706-7710
authors.initials: BO
authors.lastname: Boehm
mesh_terms: D000328:Adult; D044466:Asian People; D001323:Autoantibodies / Q000032:analysis*; D001327:Autoimmune Diseases / Q000097:blood / Q000453:epidemiology / Q000208:ethnology / Q000276:immunology*; D015551:Autoimmunity; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology / Q000208:ethnology / Q000276:immunology*; D005858:Germany / Q000453:epidemiology; D005968:Glutamate Decarboxylase / Q000037:antagonists & inhibitors*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8 / Q000037:antagonists & inhibitors*; D012017:Referral and Consultation; D012846:Singapore / Q000453:epidemiology; D062606:Tertiary Care Centers; D044465:White People; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; C516862:PTPRN protein, human; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8; D005968:Glutamate Decarboxylase