title: Interaction between oxidative stress and high-density lipoprotein cholesterol is associated with severity of coronary artery calcification in rheumatoid arthritis.
abstract: OBJECTIVE
  To test the hypothesis that oxidative stress is increased in patients with rheumatoid arthritis (RA) due to increased inflammation and contributes to the pathogenesis of atherosclerosis.
  
  
  METHODS
  The independent association between urinary F₂-isoprostane excretion, a measure of oxidative stress, and RA was tested using multiple linear regression models in 169 patients with RA and 92 control subjects, frequency matched for age, race, and sex. The relationship between F₂-isoprostane excretion and coronary calcium, a marker of atherosclerosis, was examined in multivariable proportional odds logistic regression models that also assessed the interactions between oxidative stress and low-density lipoprotein and high-density lipoprotein (HDL) cholesterol.
  
  
  RESULTS
  F₂-isoprostane excretion was significantly higher in patients with RA (median 2.75 [interquartile range (IQR) 1.60-4.06] ng/mg creatinine) than in control subjects (median 1.86 [IQR 1.25-2.62] ng/mg creatinine; adjusted P = 0.006). In patients with RA, F₂-isoprostanes were positively correlated with body mass index (P < 0.001), but not with disease activity or mediators of inflammation such as the Disease Activity Score in 28 joints or serum tumor necrosis factor α, interleukin-6, and C-reactive protein concentrations in adjusted multivariable models (P > 0.05 for all). In patients with RA, F₂-isoprostanes significantly modified the effect of HDL cholesterol on coronary calcification (P = 0.02 for interaction) after adjustment for age, sex, and race. As F₂-isoprostane levels increased, HDL lost its protective effect against coronary calcification.
  
  
  CONCLUSIONS
  Oxidative stress measured as F₂-isoprostane excretion was higher in patients with RA than in control subjects. Among patients with RA, higher F₂-isoprostane excretion and HDL cholesterol concentrations interacted significantly and were positively associated with the severity of coronary calcification.
authors.affiliation: Vanderbilt University, Nashville, Tennessee 37232-6602, USA.
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Rho
authors.forename: Cecilia P
authors.initials: CP
authors.lastname: Chung
authors.forename: Annette
authors.initials: A
authors.lastname: Oeser
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Solus
authors.forename: Tebeb
authors.initials: T
authors.lastname: Gebretsadik
authors.forename: Ayumi
authors.initials: A
authors.lastname: Shintani
authors.forename: Paolo
authors.initials: P
authors.lastname: Raggi
authors.forename: Ginger L
authors.initials: GL
authors.lastname: Milne
authors.forename: C Michael
authors.initials: CM
authors.lastname: Stein
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000473:pathology / Q000652:urine; D015415:Biomarkers / Q000097:blood / Q000652:urine; D002114:Calcinosis / Q000097:blood* / Q000473:pathology / Q000652:urine; D008076:Cholesterol, HDL / Q000097:blood*; D003324:Coronary Artery Disease / Q000097:blood* / Q000473:pathology / Q000652:urine; D003430:Cross-Sectional Studies; D028441:F2-Isoprostanes / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D012307:Risk Factors; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D008076:Cholesterol, HDL; D028441:F2-Isoprostanes