title: Irisin in the Glucose Continuum.
abstract: OBJECTIVE
  Irisin, a novel myokine has been involved in the pathogenesis of type 2 diabetes (T2D) and metabolic syndrome. The aim of the current study was to investigate this association by comparing individuals from the whole spectrum of carbohydrate disturbances.
  
  
  METHODS
  A total of 160 subjects participated in the study - 50 had normal glucose tolerance (NGT), 60 had prediabetes (PreDM), 50 had T2D. Subjects in the 3 groups were age, sex and BMI-matched. Standard OGTTs were performed for the distribution of patients in each group. Circulating serum irisin was measured by ELISA method.
  
  
  RESULTS
  Mean age of the participants of the study was 48.8 (± 7.97) years. Circulating irisin levels were statistically different in the 3 study groups - highest in NGT - median 619 ng/ml (IQR=567), lower in PreDM - 314 ng/ml (IQR=577) and lowest in T2D - 228 ng/ml (IQR=200). In males, irisin correlated positively with BMI (r=0.475, p<0.001), negatively with fasting glucose (r=- 0.547, p<0.001) and negatively with hepatic enzymes: ALT (r=- 0.281, p<0.05), AST (r=- 0.153, p>0.05), GGT (r=- 0.293, p<0.05). Similar correlations were observed in females. ROC analyses established irisin suitable for distinguishing T2D subjects from those without the condition (AUC=0.779, p<0.001) and insulin resistance (AUC=0.679, p=0.009), but not for MetS or dyslipidaemia. In a binary logistic regression model, after adjustment for confounders, irisin of ≤658 ng/ml had an OR of 7.125 for T2D in females.
  
  
  CONCLUSIONS
  Circulating irisin levels progressively decreased with the worsening of the glucose tolerance. Irisin correlated well with traditional biochemical and anthropometric parameters of metabolic health.
authors.affiliation: Clinic of Endocrinology, University Hospital "Alexandrovska", Medical University - Sofia, Sofia, Bulgaria.
authors.forename: Y
authors.initials: Y
authors.lastname: Assyov
authors.affiliation: Clinic of Endocrinology, University Hospital "Alexandrovska", Medical University - Sofia, Sofia, Bulgaria.
authors.forename: A
authors.initials: A
authors.lastname: Gateva
authors.affiliation: Central Clinical Laboratory, University Hospital "Alexandrovska", Medical University - Sofia, Sofia, Bulgaria.
authors.forename: A
authors.initials: A
authors.lastname: Tsakova
authors.affiliation: Clinic of Endocrinology, University Hospital "Alexandrovska", Medical University - Sofia, Sofia, Bulgaria.
authors.forename: Z
authors.initials: Z
authors.lastname: Kamenov
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D005353:Fibronectins / Q000097:blood*; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D008875:Middle Aged; D008954:Models, Biological
chemical_list: D001786:Blood Glucose; C577593:FNDC5 protein, human; D005353:Fibronectins