title: A novel inflammatory biomarker, GlycA, associates with disease activity in rheumatoid arthritis and cardio-metabolic risk in BMI-matched controls.
abstract: BACKGROUND
  RA and CVD both have inflammation as part of the underlying biology. Our objective was to explore the relationships of GlycA, a measure of glycosylated acute phase proteins, with inflammation and cardiometabolic risk in RA, and explore whether these relationships were similar to those for persons without RA.
  
  
  METHODS
  Plasma GlycA was determined for 50 individuals with mild-moderate RA disease activity and 39 controls matched for age, gender, and body mass index (BMI). Regression analyses were performed to assess relationships between GlycA and important markers of traditional inflammation and cardio-metabolic health: inflammatory cytokines, disease activity, measures of adiposity and insulin resistance.
  
  
  RESULTS
  On average, RA activity was low (DAS-28 = 3.0 ± 1.4). Traditional inflammatory markers, ESR, hsCRP, IL-1β, IL-6, IL-18 and TNF-α were greater in RA versus controls (P < 0.05 for all). GlycA concentrations were significantly elevated in RA versus controls (P = 0.036). In RA, greater GlycA associated with disease activity (DAS-28; RDAS-28 = 0.5) and inflammation (RESR = 0.7, RhsCRP = 0.7, RIL-6 = 0.3: P < 0.05 for all); in BMI-matched controls, these inflammatory associations were absent or weaker (hsCRP), but GlycA was related to IL-18 (RhsCRP = 0.3, RIL-18 = 0.4: P < 0.05). In RA, greater GlycA associated with more total abdominal adiposity and less muscle density (Rabdominal-adiposity = 0.3, Rmuscle-density = -0.3, P < 0.05 for both). In BMI-matched controls, GlycA associated with more cardio-metabolic markers: BMI, waist circumference, adiposity measures and insulin resistance (R = 0.3-0.6, P < 0.05 for all).
  
  
  CONCLUSIONS
  GlycA provides an integrated measure of inflammation with contributions from traditional inflammatory markers and cardio-metabolic sources, dominated by inflammatory markers in persons with RA and cardio-metabolic factors in those without.
authors.affiliation: Department of Medicine and Duke Molecular Physiology Institute, Duke School of Medicine, Durham, NC, USA.
authors.forename: David B
authors.initials: DB
authors.lastname: Bartlett
authors.affiliation: LipoScience, Laboratory Corporation of America® Holdings, Raleigh, NC, USA.
authors.forename: Margery A
authors.initials: MA
authors.lastname: Connelly
authors.affiliation: Department of Medicine and Duke Molecular Physiology Institute, Duke School of Medicine, Durham, NC, USA.
authors.forename: Hiba
authors.initials: H
authors.lastname: AbouAssi
authors.affiliation: Center for Health Promotion and Disease Prevention, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors.forename: Lori A
authors.initials: LA
authors.lastname: Bateman
authors.affiliation: Center for Health Promotion and Disease Prevention, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors.forename: K Noelle
authors.initials: KN
authors.lastname: Tune
authors.affiliation: Department of Medicine and Duke Molecular Physiology Institute, Duke School of Medicine, Durham, NC, USA.
authors.forename: Janet L
authors.initials: JL
authors.lastname: Huebner
authors.affiliation: Department of Medicine and Duke Molecular Physiology Institute, Duke School of Medicine, Durham, NC, USA.
authors.forename: Virginia B
authors.initials: VB
authors.lastname: Kraus
authors.affiliation: LipoScience, Laboratory Corporation of America® Holdings, Raleigh, NC, USA.
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Winegar
authors.affiliation: LipoScience, Laboratory Corporation of America® Holdings, Raleigh, NC, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Otvos
authors.affiliation: Department of Medicine and Duke Molecular Physiology Institute, Duke School of Medicine, Durham, NC, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Kraus
authors.affiliation: Department of Medicine and Duke Molecular Physiology Institute, Duke School of Medicine, Durham, NC, USA. Huffm007@mc.duke.edu.
authors.forename: Kim M
authors.initials: KM
authors.lastname: Huffman
mesh_terms: D000209:Acute-Phase Proteins / Q000032:analysis*; D050154:Adiposity / Q000502:physiology; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000150:complications / Q000473:pathology; D015415:Biomarkers / Q000097:blood*; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000097:blood / Q000150:complications; D003430:Cross-Sectional Studies; D005260:Female; D006031:Glycosylation; D006801:Humans; D007249:Inflammation / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D012307:Risk Factors
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers
keywords: Biomarker; Glycosylation; Inflammation; Metabolic syndrome; Rheumatoid arthritis