title: Elevated circulating adiponectin in type 1 diabetes is associated with long diabetes duration.
abstract: OBJECTIVE
  To study circulating adiponectin concentrations in relation to diabetes duration and endogenous insulin secretion in patients with type 1 diabetes.
  
  
  METHODS
  Patients with haemoglobin A1c (HbA1c) < 6% (reference range 3.6-5.4%) were selected for the study. Twenty-two men and 24 women [age 41.3 +/- 13.8 years (mean +/- SD), diabetes duration 4 months to 52 years] participated. Healthy controls (15 women and nine men, age 41.3 +/- 13.0 years) were also included. Overnight fasting serum samples were analysed for adiponectin, HbA1c, C-peptide and lipoproteins.
  
  
  RESULTS
  Significant positive associations were found between adiponectin concentrations and diabetes duration in univariate and multiple regression analyses. Serum adiponectin averaged 9.7 +/- 5.3 [median 8.1, interquartile range (IQR) 3.6] mg/l in patients with diabetes duration less than 10 years and 17.8 +/- 10.7 (median 14.7, IQR 7.5) mg/l in patients with longer duration (P = 0.0001). Among the patients, 24 were without detectable (< 100 pmol/l) and 22 with detectable C-peptide levels (185 +/- 91 pmol/l). C-peptide levels in controls averaged 492 +/- 177 pmol/l. HbA1c was 5.7 +/- 0.6% in patients without detectable C-peptide and 5.6 +/- 0.4% in patients with detectable C-peptide (ns). Serum adiponectin was higher in patients without detectable C-peptide than in patients with detectable C-peptide [17.3 +/- 11.1 vs. 10.6 +/- 5.8 mg/l (P < 0.005)] and in the controls [10.1 +/- 2.9 mg/l (P < 0.001 vs. patients without detectable C-peptide)].
  
  
  CONCLUSIONS
  The increase in circulating adiponectin concentrations in patients with type 1 diabetes appears to be strongly associated with long diabetes duration, irrespective of the metabolic control. Among other factors, a putative role for residual beta-cell function in the regulation of circulating adiponectin levels can be considered but we did not find sufficient evidence for this in the present study.
authors.affiliation: Diabetes Centre, Division of Internal Medicine, Department of Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden. torbjorn.lindstrom@lio.se
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Lindström
authors.forename: Jan
authors.initials: J
authors.lastname: Frystyk
authors.forename: Christina A
authors.initials: CA
authors.lastname: Hedman
authors.forename: Allan
authors.initials: A
authors.lastname: Flyvbjerg
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Arnqvist
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D002096:C-Peptide / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D018709:Statistics, Nonparametric; D013997:Time Factors
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D002096:C-Peptide; D007328:Insulin