title: Chronic subclinical inflammation as part of the insulin resistance syndrome: the Insulin Resistance Atherosclerosis Study (IRAS).
abstract: BACKGROUND
  Inflammation has been suggested as a risk factor for the development of atherosclerosis. Recently, some components of the insulin resistance syndrome (IRS) have been related to inflammatory markers. We hypothesized that insulin insensitivity, as directly measured, may be associated with inflammation in nondiabetic subjects.
  
  
  RESULTS
  We studied the relation of C-reactive protein (CRP), fibrinogen, and white cell count to components of IRS in the nondiabetic population of the Insulin Resistance Atherosclerosis Study (IRAS) (n=1008; age, 40 to 69 years; 33% with impaired glucose tolerance), a multicenter, population-based study. None of the subjects had clinical coronary artery disease. Insulin sensitivity (S(I)) was measured by a frequently sampled intravenous glucose tolerance test, and CRP was measured by a highly sensitive competitive immunoassay. All 3 inflammatory markers were correlated with several components of the IRS. Strong associations were found between CRP and measures of body fat (body mass index, waist circumference), S(I), and fasting insulin and proinsulin (all correlation coefficients >0.3, P<0.0001). The associations were consistent among the 3 ethnic groups of the IRAS. There was a linear increase in CRP levels with an increase in the number of metabolic disorders. Body mass index, systolic blood pressure, and S(I) were related to CRP levels in a multivariate linear regression model.
  
  
  CONCLUSIONS
  We suggest that chronic subclinical inflammation is part of IRS. CRP, a predictor of cardiovascular events in previous reports, was independently related to S(I). These findings suggest potential benefits of anti-inflammatory or insulin-sensitizing treatment strategies in healthy individuals with features of IRS.
authors.affiliation: Department of Medicine, University of Texas Health Science Center at San Antonio, 78228-3900, USA. festa@magnet.at
authors.forename: A
authors.initials: A
authors.lastname: Festa
authors.forename: R
authors.initials: R
authors.lastname: D'Agostino
authors.forename: G
authors.initials: G
authors.lastname: Howard
authors.forename: L
authors.initials: L
authors.lastname: Mykkänen
authors.forename: R P
authors.initials: RP
authors.lastname: Tracy
authors.forename: S M
authors.initials: SM
authors.lastname: Haffner
mesh_terms: D000328:Adult; D000368:Aged; D001161:Arteriosclerosis / Q000208:ethnology / Q000276:immunology*; D015415:Biomarkers; D002097:C-Reactive Protein / Q000032:analysis; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006801:Humans; D007333:Insulin Resistance / Q000276:immunology*; D007958:Leukocyte Count; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood
chemical_list: D015415:Biomarkers; D014280:Triglycerides; D005340:Fibrinogen; D002097:C-Reactive Protein