title: Lower omega-3 fatty acids are associated with the presence of anti-cyclic citrullinated peptide autoantibodies in a population at risk for future rheumatoid arthritis: a nested case-control study.
abstract: OBJECTIVE
  The aim of this study was to investigate omega-3 fatty acid (FA) supplement use and omega-3 FAs in erythrocyte membranes [omega-3 FA % in erythrocyte membranes (RBC)] and their association with anti-CCP autoantibodies in a population without RA, but who are at genetic risk for RA.
  
  
  METHODS
  The multicentre Studies of the Etiology of RA (SERA) cohort includes RA-free subjects who are first-degree relatives of RA probands or are enriched with the HLA-DR4 allele. In a nested case-control study, 30 SERA cases were identified who were anti-CCP2 antibody positive. We further identified 47 autoantibody negative controls, frequency matched to cases on age at study visit, sex, race and study site. Anti-CCP2 status, self-reported omega-3 FA supplement use and omega-3 FA % in RBCs were obtained from a single visit.
  
  
  RESULTS
  Anti-CCP2 positive cases were less likely than controls to report omega-3 FA supplement use (odds ratio: 0.14; 95% CI 0.03, 0.68). In addition, the likelihood of anti-CCP2 positivity was inversely associated with total omega-3 FA % in RBCs (odds ratio: 0.47; 95% CI 0.24, 0.92, for a s.d. increase).
  
  
  CONCLUSIONS
  The inverse association between anti-CCP2 positivity and self-reported omega-3 FA supplement use and omega-3 FA % in RBCs suggests that omega-3 FAs may protect against the development of RA-related autoimmunity in pre-clinical RA.
authors.affiliation: Colorado School of Public Health, Department of Epidemiology, Aurora.
authors.forename: Ryan W
authors.initials: RW
authors.lastname: Gan
authors.affiliation: Colorado School of Public Health, Department of Epidemiology, Aurora.
authors.forename: Kendra A
authors.initials: KA
authors.lastname: Young
authors.affiliation: Colorado School of Public Health, Department of Biostatistics and Informatics.
authors.forename: Gary O
authors.initials: GO
authors.lastname: Zerbe
authors.affiliation: University of Colorado, Division of Rheumatology, Aurora, CO.
authors.forename: M Kristen
authors.initials: MK
authors.lastname: Demoruelle
authors.affiliation: Cedars-Sinai Medical Center, Los Angeles, CA.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Weisman
authors.affiliation: Benaroya Research Institute at Virginia Mason, Seattle, WA.
authors.forename: Jane H
authors.initials: JH
authors.lastname: Buckner
authors.affiliation: Feinstein Institute for Medical Research and North Shore - Long Island Jewish Health System, Manhasset, NY.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Gregersen
authors.affiliation: Veteran Affairs Nebraska Western Iowa Health Care System and University of Nebraska Medical Center, Omaha, NE.
authors.forename: Ted R
authors.initials: TR
authors.lastname: Mikuls
authors.affiliation: Veteran Affairs Nebraska Western Iowa Health Care System and University of Nebraska Medical Center, Omaha, NE.
authors.forename: James R
authors.initials: JR
authors.lastname: O'Dell
authors.affiliation: Scripps Health, La Jolla and.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Keating
authors.affiliation: Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Clare-Salzler
authors.affiliation: University of Colorado, Division of Rheumatology, Aurora, CO.
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Deane
authors.affiliation: University of Colorado, Division of Rheumatology, Aurora, CO.
authors.forename: V Michael
authors.initials: VM
authors.lastname: Holers
authors.affiliation: Colorado School of Public Health, Department of Epidemiology, Aurora, Jill.Norris@ucdenver.edu.
authors.forename: Jill M
authors.initials: JM
authors.lastname: Norris
mesh_terms: D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000188:drug therapy / Q000453:epidemiology; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000097:blood / Q000276:immunology*; D011159:Population Surveillance; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
chemical_list: D001323:Autoantibodies; D015525:Fatty Acids, Omega-3; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide
keywords: autoantibodies; epidemiology; rheumatoid arthritis