title: Association of inflammation with worsening HOMA-insulin resistance.
abstract: OBJECTIVE
  We examined the cross-sectional and longitudinal relationships between C-reactive protein (CRP), a marker of low-grade inflammation, and insulin resistance and whether the association was independent of obesity and oxidative stress.
  
  
  METHODS
  CRP and insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR]) data were obtained in a population-based, prospective observational study, Coronary Artery Risk Development in Young Adults (CARDIA), during 1992-2006.
  
  
  RESULTS
  CRP showed a significant positive association with insulin resistance, both cross-sectionally and longitudinally (5 year follow-up). The estimated increment in HOMA-IR was 0.34 log(e)(pmol/l x [mmol/l]/156.25) (p value for trend <0.0001) in the highest vs lowest CRP quartiles in cross-sectional analysis, whereas the corresponding estimate was 0.12 (p trend <0.0001) in the highest vs lowest CRP quartiles longitudinally over 5 years. The gradient of HOMA-IR across CRP was attenuated but remained statistically significant after controlling for body fat measurements (0.06 in the highest vs lowest CRP in both cross-sectional [p value for trend = 0.001] and longitudinal analyses [p value for trend = 0.01]), and was little changed by further adjustment for oxidative stress markers (F(2)-isoprostanes and oxidised LDL). There were consistent increments in the levels of HOMA-IR with increasing concentrations of CRP over time. In contrast, higher HOMA-IR did not predict future increases in CRP. Findings were similar using fibrinogen as the predictor variable.
  
  
  CONCLUSIONS
  Although a substantial portion of this association was explained by obesity, CRP was independently related to concurrent and future insulin resistance.
authors.affiliation: Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, 1300 South 2nd Street, Suite 300, Minneapolis, MN 55454, USA.
authors.forename: K
authors.initials: K
authors.lastname: Park
authors.forename: M
authors.initials: M
authors.lastname: Steffes
authors.forename: D-H
authors.initials: DH
authors.lastname: Lee
authors.forename: J H
authors.initials: JH
authors.lastname: Himes
authors.forename: D R
authors.initials: DR
authors.lastname: Jacobs
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism*; D003324:Coronary Artery Disease / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003710:Demography; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006706:Homeostasis; D006801:Humans; D007249:Inflammation / Q000097:blood*; D007333:Insulin Resistance / Q000502:physiology*; D008019:Life Style; D008137:Longitudinal Studies; D008297:Male; D013997:Time Factors; D055105:Waist Circumference
chemical_list: D002097:C-Reactive Protein
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