A prospective study of eating disorders and risk of rheumatoid arthritis

Background: Eating disorders (EDs) are associated with a higher risk of autoimmune diseases, including type 1 diabetes and Crohn's disease. However, prospective cohort studies regarding EDs and future risk of rheumatoid arthritis (RA) remain limited. This study aimed to investigate the prospective association of overall and specific types of ED with the risk of RA, and to determine if these associations vary by sex. Methods: This study included 489,569 UK Biobank participants aged 40 to 69 who were free of RA at baseline (2006–2010). EDs were identified from self-reports, hospital inpatient records, and primary care data. Incident RA cases were identified using data from primary care, hospital inpatient admissions, death record data, and self-reported medical conditions. Multivariable-adjusted Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs). Results: Over a median follow-up of 12.5 years, 5404 incident RA cases were documented. Individuals with a history of ED had a higher risk of developing RA compared to those without (adjusted HR = 1.76 [95 % CI, 1.12–2.76]) after adjusting for sociodemographic factors, lifestyle factors, and genetic predisposition to RA. The association between EDs and RA was stronger among men (adjusted HR, 5.09 [95 % CI, 2.13–12.1]) than women (adjusted HR, 1.38 [95 % CI, 0.82–2.34]) (p for interaction = 0.033). Conclusion: Our findings suggest that individuals with EDs may have a higher risk of developing RA, particularly in men. Further research is warranted to replicate our results and to explore the underlying mechanisms.