Association of Lipid Mediators With Development of Future Incident Inflammatory Arthritis in an Anti–Citrullinated Protein Antibody–Positive Population

Objective: To determine the association of polyunsaturated fatty acid (PUFA)–derived lipid mediators with progression from rheumatoid arthritis (RA)–related autoimmunity to inflammatory arthritis (IA). Methods: We conducted a prospective cohort study using data from the Studies of the Etiology of Rheumatoid Arthritis (SERA). SERA enrolled first-degree relatives (FDRs) of individuals with RA (FDR cohort) and individuals who screened positive for RA-related autoantibodies at health fairs (screened cohort). We followed up 133 anti–cyclic citrullinated peptide 3.1 (anti-CCP3.1)–positive participants, 29 of whom developed IA. Lipid mediators selected a priori were quantified from stored plasma samples using liquid chromatography tandem mass spectrometry. We fit multivariable Cox proportional hazards models for each lipid mediator as a time-varying variable. For lipid mediators found to be significantly associated with IA, we then examined interleukin-1β (IL-1β), IL-6, IL-8, and tumor necrosis factor (TNF) as potential statistical mediators. Results: For every 1 natural log pg/ml increase in the circulating plasma levels of proinflammatory 5-HETE, the risk of developing IA increased by 241% (hazard ratio 2.41 [95% confidence interval 1.43–4.07]) after adjusting for age at baseline, cohort (FDR or screened), and shared epitope status. The models examining 15-HETE and 17-HDHA had the same trend but did not reach significance. We did not find evidence that the association between 5-HETE and IA risk was influenced by the proinflammatory cytokines tested. Conclusion: In a prospective cohort of anti-CCP–positive individuals, higher levels of 5-HETE, an important precursor to proinflammatory leukotrienes, is associated with subsequent IA. Our findings highlight the potential significance of these PUFA metabolites in pre-RA populations.