Omega-3 fatty acids are associated with a lower prevalence of autoantibodies in shared epitope-positive subjects at risk for rheumatoid arthritis

• Published in: Annals of the rheumatic diseases Vol. 76; no. 1; pp. 147 - 152
• Main Authors: Gan, Ryan W, Demoruelle, M Kristen, Deane, Kevin D, Weisman, Michael H, Buckner, Jane H, Gregersen, Peter K, Mikuls, Ted R, O'Dell, James R, Keating, Richard M, Fingerlin, Tasha E, Zerbe, Gary O, Clare-Salzler, Michael J, Holers, V Michael, Norris, Jill M
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01.01.2017
• Subjects: Adult; Antigens; Arthritis, Rheumatoid - blood; Arthritis, Rheumatoid - immunology; Autoantibodies - blood; Biomarkers; Biomarkers - blood; Blood & organ donations; Case-Control Studies; Cell Membrane - chemistry; Diabetes; Dietary Supplements; Epitopes - immunology; Erythrocytes - chemistry; Fatty acids; Fatty Acids, Omega-3 - administration & dosage; Fatty Acids, Omega-3 - analysis; Fatty Acids, Omega-3 - blood; Female; Humans; Male; Middle Aged; Peptides, Cyclic - immunology; Prospective Studies; Protective Factors; Rheumatoid arthritis; Rheumatoid Factor - immunology; Risk Factors; United States > US; Rheumatoid Arthritis; Epidemiology; Autoantibodies
• ISSN: 0003-4967; 1468-2060
• DOI: 10.1136/annrheumdis-2016-209154

ObjectivesPreviously, we found that omega-3 fatty acids (n-3 FAs) were inversely associated with anti-cyclic citrullinated peptide (anti-CCP) positivity in participants at risk for future rheumatoid arthritis (RA). We investigated whether n-3 FAs were also associated with rheumatoid factor (RF) positivity and whether these associations were modified by shared epitope (SE) positivity.MethodsThe Studies of the Etiology of RA (SERA) cohort includes RA-free participants who are at increased risk for RA. We conducted a nested case–control study (n=136) to determine the association between RF and anti-CCP2 positivity and n-3 FA percentage in erythrocyte membranes (n-3 FA% in red blood cells (RBCs)). Additionally, in the baseline visit of the SERA cohort (n=2166), we evaluated the association between reported n-3 FA supplement use and prevalence of RF and anti-CCP2. We assessed SE positivity as an effect modifier.ResultsIn the case–control study, increasing n-3 FA% in RBCs was inversely associated with RF positivity in SE-positive participants (OR 0.27, 95% CI 0.10 to 0.79), but not SE-negative participants. Similar associations were seen with anti-CCP positivity in SE-positive participants (OR 0.42, 95% CI 0.20 to 0.89), but not SE-negative participants. In the SERA cohort at baseline, n-3 FA supplement use was associated with a lower prevalence of RF positivity in SE-positive participants (OR 0.32, 95% CI 0.12 to 0.82), but not SE-negative participants; similar but non-significant trends were observed with anti-CCP2.ConclusionsThe potential protective effect of n-3 FAs on RA-related autoimmunity may be most pronounced in those who exhibit HLA class II genetic susceptibility to RA.