title: Glucose-independent ethnic differences in HbA1c in people without known diabetes.
abstract: OBJECTIVE
  To determine whether glucose-independent differences in HbA1c exist between people of African, South Asian, and Chinese ethnicities.
  
  
  METHODS
  Data from 6,701 people aged 19-78 years, without known diabetes, from Mauritius, and participating in the population-based Non-Communicable Disease Surveys of the main island and the island of Rodrigues were included. Participants were African (n = 1,219 from main island, n = 1,505 from Rodrigues), South Asian (n = 3,820), and Chinese (n = 157). Survey data included HbA1c, plasma glucose during oral glucose tolerance testing (OGTT), anthropometry, demographics, and medical and lifestyle history.
  
  
  RESULTS
  Mean HbA1c, after adjustment for fasting and 2-h plasma glucose and other factors known to influence HbA1c, was higher in Africans from Rodrigues (6.1%) than in South Asians (5.7%, P < 0.001), Chinese (5.7%, P < 0.001), or Africans from the main island of Mauritius (5.7%, P < 0.001). The age-standardized prevalence of diabetes among Africans from Rodrigues differed substantially depending on the diagnostic criteria used [OGTT 7.9% (95% CI 5.8-10.0); HbA1c 17.3% (15.3-19.2)]. Changing diagnostic criteria resulted in no significant change in the prevalence of diabetes within the other ethnic groups.
  
  
  CONCLUSIONS
  People of African ethnicity from Rodrigues have higher HbA1c than those of South Asian or African ethnicity from the main island of Mauritius for reasons not explained by plasma glucose during an OGTT or traditional factors known to affect glycemia. Further research should be directed at determining the mechanism behind this disparity and its relevance to clinical outcomes.
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Australia. matthew.hare@bakeridi.edu.au
authors.forename: Matthew J L
authors.initials: MJ
authors.lastname: Hare
authors.forename: Dianna J
authors.initials: DJ
authors.lastname: Magliano
authors.forename: Paul Z
authors.initials: PZ
authors.lastname: Zimmet
authors.forename: Stefan
authors.initials: S
authors.lastname: Söderberg
authors.forename: Noorjehan
authors.initials: N
authors.lastname: Joonas
authors.forename: Vassen
authors.initials: V
authors.lastname: Pauvaday
authors.forename: José
authors.initials: J
authors.lastname: Larhubarbe
authors.forename: Jaakko
authors.initials: J
authors.lastname: Tuomilehto
authors.forename: Sudhir
authors.initials: S
authors.lastname: Kowlessur
authors.forename: K George M M
authors.initials: KG
authors.lastname: Alberti
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Shaw
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D003920:Diabetes Mellitus / Q000208:ethnology* / Q000378:metabolism*; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin