title: Adipokines, insulin resistance, and coronary artery calcification.
abstract: OBJECTIVE
  We evaluated the hypothesis that plasma levels of adiponectin and leptin are independently but oppositely associated with coronary artery calcification (CAC), a measure of subclinical atherosclerosis. In addition, we assessed which biomarkers of adiposity and insulin resistance are the strongest predictors of CAC beyond traditional risk factors, metabolic syndrome, and plasma C-reactive protein (CRP).
  
  
  BACKGROUND
  Adipokines are fat-secreted biomolecules with pleiotropic actions that converge in diabetes and cardiovascular disease.
  
  
  METHODS
  We examined the association of plasma adipocytokines with CAC in 860 asymptomatic, nondiabetic participants in the SIRCA (Study of Inherited Risk of Coronary Atherosclerosis).
  
  
  RESULTS
  Plasma adiponectin and leptin levels had opposite and distinct associations with adiposity, insulin resistance, and inflammation. Plasma leptin was positively (top vs. bottom quartile) associated with higher CAC after adjustment for age, gender, traditional risk factors, and Framingham risk scores (tobit regression ratio 2.42 (95% confidence interval [CI]: 1.48 to 3.95; p = 0.002) and further adjustment for metabolic syndrome and CRP (tobit regression ratio: 2.31; 95% CI: 1.36 to 3.94; p = 0.002). In contrast, adiponectin levels were not associated with CAC. Comparative analyses suggested that levels of leptin, interleukin-6, and soluble tumor necrosis factor receptor-2, as well as the homeostasis model assessment of insulin resistance (HOMA-IR) index, predicted CAC scores, but only leptin and HOMA-IR provided value beyond risk factors, metabolic syndrome, and CRP.
  
  
  CONCLUSIONS
  In SIRCA, although both leptin and adiponectin levels were associated with metabolic and inflammatory markers, only leptin was a significant independent predictor of CAC. Of several metabolic markers, leptin and the HOMA-IR index had the most robust, independent associations with CAC.
authors.affiliation: Cardiovascular Institute and Institute for Translational Medicine and Therapeutics, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: Atif
authors.initials: A
authors.lastname: Qasim
authors.forename: Nehal N
authors.initials: NN
authors.lastname: Mehta
authors.forename: Mahlet G
authors.initials: MG
authors.lastname: Tadesse
authors.forename: Megan L
authors.initials: ML
authors.lastname: Wolfe
authors.forename: Thomas
authors.initials: T
authors.lastname: Rhodes
authors.forename: Cynthia
authors.initials: C
authors.lastname: Girman
authors.forename: Muredach P
authors.initials: MP
authors.lastname: Reilly
mesh_terms: D054392:Adipokines / Q000097:blood*; D050154:Adiposity; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D002114:Calcinosis / Q000097:blood*; D003324:Coronary Artery Disease / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D020738:Leptin / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D008875:Middle Aged; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: D054392:Adipokines; D015415:Biomarkers; D020738:Leptin; D002097:C-Reactive Protein