The potential protective effect of omega-3 fatty acids (n-3 FAs) on rheumatoid arthritis (RA) -related autoimmunity may be most pronounced in those who exhibit human leukocyte antigen (HLA) class II genetic susceptibility to RA, a recent study found. Researchers evaluated The Studies of the Etiology of RA (SERA) cohort, which included RA-free participants who are at increased risk for RA. They conducted a nested case-control study (n=136) to determine the association between rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP2) positivity and n-3 FA percentage in erythrocyte membranes (n-3 FA% in red blood cells). Additionally, in the baseline visit of the SERA cohort (n=2,166), they evaluated the association between reported n-3 FA supplement use and prevalence of RF and anti-CCP2. They found:

• In the case-control study, increasing n-3 FA% in red blood cells was inversely associated with RF positivity in shared epitope (SE)-positive participants, but not SE-negative participants.

• Similar associations were seen with anti-CCP2 positivity in SE-positive participants, 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, but not SE-negative participants; similar, but non-significant, trends were observed with anti-CCP2.

Citation: Gan RW, Demoruelle MK, Deane KD, et al. Omega-3 fatty acids are associated with a lower prevalence of autoantibodies in shared epitope-positive subjects at risk for rheumatoid arthritis. [Published online ahead of print May 17, 2016]. Ann Rheum Dis. doi:10.1136/annrheumdis-2016-209154.