title: Haemoglobin A1c is not a surrogate for glucose and insulin measures for investigating the early life and childhood determinants of insulin resistance and Type 2 diabetes in healthy children. An analysis from the Avon Longitudinal Study of Parents and Children (ALSPAC).
abstract: OBJECTIVE
  Research into early life and childhood determinants of insulin resistance and Type 2 diabetes are complicated by requirements for fasting blood samples and glucose tolerance tests. We investigated haemoglobin A(1c) (HbA(1c)), a marker of glycaemia measured in non-fasting blood, as an alternative.
  
  
  METHODS
  HbA(1c) was measured in 1645 children aged 9-11 years without diabetes from the Avon Longitudinal Study of Parents and Children. Thirty-nine children had two HbA(1c) measurements. Data on parental, child and potential confounding factors were collected prospectively from questionnaires, medical records and direct examination. Data from a shortened 30-min oral glucose tolerance test were available for 431 children at age 8 years. Body composition was measured by dual-energy X-ray absorptiometry.
  
  
  RESULTS
  Mean (sd) HbA(1c) was 4.91(0.29)%. HbA(1c) increased with age and was higher in boys compared with girls, non-white compared with white children, and in children with anaemia. Mean difference between repeated HbA(1c) measurements was 0.01%. HbA(1c) was weakly positively associated with fasting glucose (beta = 0.066%/mmol/l, P = 0.05), but was not associated with 30-min glucose, fasting or 30-min insulin, or homeostasis model assessment-insulin resistance. HbA(1c) was weakly inversely associated with weight sd score (beta =-0.02%/unit, P = 0.004), body mass index sd score (beta = -0.02%/unit, P = 0.002), and total body fat (beta = -0.003%/kg, P = 0.06) and lean mass (beta = -0.011%/kg, P = 0.01), but was not associated with birthweight or breastfeeding.
  
  
  CONCLUSIONS
  HbA(1c) is not a good marker of fasting or post-load glucose and insulin measures in healthy children, and is not a viable alternative to these measures for investigating the determinants of insulin resistance and Type 2 diabetes in children.
authors.affiliation: Department of Social Medicine, University of Bristol, UK. shultisw@mail.nih.gov
authors.forename: W A
authors.initials: WA
authors.lastname: Shultis
authors.forename: S D
authors.initials: SD
authors.lastname: Leary
authors.forename: A R
authors.initials: AR
authors.lastname: Ness
authors.forename: J
authors.initials: J
authors.lastname: Scott
authors.forename: R M
authors.initials: RM
authors.lastname: Martin
authors.forename: P H
authors.initials: PH
authors.lastname: Whincup
authors.forename: G Davey
authors.initials: GD
authors.lastname: Smith
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis*; D005215:Fasting / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test / Q000379:methods; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D008137:Longitudinal Studies; D008297:Male
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin