title: Glycated haemoglobin variations in paediatric type 1 diabetes: the impact of season, gender and age.
abstract: OBJECTIVE
  To study whether monthly variations in type 1 diabetes incidence are related to monthly glycated haemoglobin (HbA1c) levels at diagnosis and if high HbA1c at diagnosis is related to certain clinical variables at diagnosis and during the clinical course of the disease.
  
  
  METHODS
  Data from 4430 boys and 3590 girls registered in the Swedish paediatric diabetes quality registry, Swedish paediatric diabetes quality registry, from 2000 to 2010 were analysed.
  
  
  RESULTS
  Month of onset varied (p < 0.001), with 53% diagnosed during September to February, and mean HbA1c at diagnosis was highest in May (10.9%, 96 mmol/mol) and lowest in (October 9.4%, 88 mmol/mol) (p < 0.001). Girls showed higher HbA1c at onset than boys (p < 0.001). More than half (53%) with an annual mean HbA1c of >9.3% (78 mmol/mol) and 4% of those with an annual mean of <7.4% (57 mmol/mol) in 2007 had >9.3% (78 mmol/mol) in 2010.
  
  
  CONCLUSIONS
  Patients with high HbA1c levels during a certain period have the same high levels several years later. This group, perhaps including those with high HbA1c level at diagnosis, may need more intensive care, including extra support from the diabetes teams and other forms of medical treatment.
authors.affiliation: Division of Pediatrics, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Hanberger
authors.forename: K
authors.initials: K
authors.lastname: Åkesson
authors.forename: U
authors.initials: U
authors.lastname: Samuelsson
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000453:epidemiology*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D011446:Prospective Studies; D012621:Seasons; D012737:Sex Factors
chemical_list: D006442:Glycated Hemoglobin
keywords: HbA1c; Metabolic control; Quality register; Seasonal variations; Type 1 diabetes