title: Effect of ethnicity on HbA1c levels in individuals without diabetes: Systematic review and meta-analysis.
abstract: OBJECTIVE
  Disparities in HbA1c levels have been observed among ethnic groups. Most studies were performed in patients with diabetes mellitus (DM), which may interfere with results due to the high variability of glucose levels. We conducted a systematic review and meta-analysis to investigate the effect of ethnicity on HbA1c levels in individuals without DM.
  
  
  METHODS
  This is a systematic review with meta-analysis. We searched MEDLINE and EMBASE up to September 2016. Studies published after 1996, performed in adults without DM, reporting HbA1c results measured by certified/standardized methods were included. A random effects model was used and the effect size was presented as weighted HbA1c mean difference (95% CI) between different ethnicities as compared to White ethnicity.
  
  
  RESULTS
  Twelve studies met the inclusion criteria, totalling data from 49,238 individuals. There were significant differences between HbA1c levels in Blacks [0.26% (2.8 mmol/mol); 95% CI 0.18 to 0.33 (2.0 to 3.6), p <0.001; I2 = 90%, p <0.001], Asians [0.24% (2.6 mmol/mol); 95% CI 0.16 to 0.33 (1.7 to 3.6), p <0.001; I2 = 80%, p = 0.0006] and Latinos [0.08% (0.9 mmol/mol); IC 95% 0.06 to 0.10 (0.7 to 1.1); p <0.001; I2 = 0%; p = 0.72] when compared to Whites.
  
  
  CONCLUSIONS
  This meta-analysis shows that, in individuals without DM, HbA1c values are higher in Blacks, Asians, and Latinos when compared to White persons. Although small, these differences might have impact on the use of a sole HbA1c point to diagnose DM in all ethnic populations.
authors.affiliation: Graduate Program in Endocrinology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.|Centro Universitário FSG, Caxias do Sul, Brazil.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Cavagnolli
authors.affiliation: Graduate Program in Endocrinology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
authors.forename: Ana Laura
authors.initials: AL
authors.lastname: Pimentel
authors.affiliation: Graduate Program in Endocrinology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.|Laboratory of Transplantation Immunology, Santa Casa de Misericordia de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Priscila Aparecida Correa
authors.initials: PA
authors.lastname: Freitas
authors.affiliation: Graduate Program in Endocrinology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.|Endocrinology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Jorge Luiz
authors.initials: JL
authors.lastname: Gross
authors.affiliation: Graduate Program in Endocrinology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.|Endocrinology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Joíza Lins
authors.identifier: http://orcid.org/0000-0001-8834-4075
authors.initials: JL
authors.lastname: Camargo
mesh_terms: D044466:Asian People; D044383:Black People; D001786:Blood Glucose / Q000032:analysis*; D003920:Diabetes Mellitus / Q000097:blood* / Q000208:ethnology; D005006:Ethnicity; D005215:Fasting / Q000097:blood*; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D044465:White People
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin