Metabolic Syndrome Is Associated With an Increased Risk of Rheumatoid Arthritis: A Prospective Cohort Study Including 369,065 Participants.

OBJECTIVE:To explore the associations between metabolic syndrome (MetS) and its individual components and the risk of rheumatoid arthritis (RA). METHODS:A total of 369,065 individuals were included in the present study based on the UK Biobank. Multivariable Cox proportional hazards regression models were applied to estimate the associations between MetS and its individual components and the risk of RA. Mediation analysis was performed to further assess the potential mediating role of C-reactive protein (CRP) in the relationship between MetS and RA. RESULTS:During a median follow-up period of 12.04 years, a total of 4901 incident RA cases were documented. MetS (hazard ratio [HR] 1.22, 95% CI 1.14-1.30) and 4 of its 5 components (elevated waist circumference [WC; HR 1.21, 95% CI 1.12-1.32], elevated triglyceride [TG] level [HR 1.12, 95% CI 1.05-1.19], reduced high-density lipoprotein cholesterol [HDL-C] level [HR 1.31, 95% CI 1.23-1.39], and hyperglycemia [HR 1.15, 95% CI 1.05-1.25]) were associated with an increased risk of RA. In addition, the risk of RA increased as the number of diagnosed MetS components increased, with the highest risk in participants with all 5 components. Mediation analysis showed that CRP might mediate the association between MetS and RA, accounting for 9.27% of the total effect. CONCLUSION:These findings indicated positive associations between MetS and 4 of its components (WC, TG, HDL-C, and hyperglycemia) and the risk of RA, highlighting the importance of MetS management in the prevention of RA.