Objective: We aimed to determine whether specific respiratory tract diseases are associated with increased rheumatoid arthritis (RA) risk.
Methods: This case-control study within the Mass General Brigham Biobank matched newly diagnosed RA cases to 3 controls on age, sex, and electronic health record history. We identified RA using a validated algorithm and confirmed by medical record review. Respiratory tract disease exposure required 1 inpatient or 2 outpatient codes at least 2 years before the index date of RA clinical diagnosis or matched date. Logistic regression models calculated ORs for RA with 95% CIs, adjusting for confounders. We then stratified by serostatus ("seropositive" was positive rheumatoid factor and/or anticitrullinated protein antibodies) and smoking.
Results: We identified 741 RA cases and 2223 controls (both median age 55, 76% female). Acute sinusitis (OR 1.61, 95% CI 1.05-2.45), chronic sinusitis (OR 2.16, 95% CI 1.39-3.35), and asthma (OR 1.39, 95% CI 1.03-1.87) were associated with increased risk of RA. Acute respiratory tract disease burden during the preindex exposure period was also associated with increased RA risk (OR 1.30 per 10 codes, 95% CI 1.08-1.55). Acute pharyngitis was associated with seronegative (OR 1.68, 95% CI 1.02-2.74) but not seropositive RA; chronic rhinitis/pharyngitis was associated with seropositive (OR 2.46, 95% CI 1.01-5.99) but not seronegative RA. Respiratory tract diseases tended towards higher associations in smokers, especially > 10 pack-years (OR 1.52, 95% CI 1.02-2.27, P = 0.10 for interaction).
Conclusion: Acute and chronic sinusitis, pharyngitis, and acute respiratory burden increased RA risk. The mucosal paradigm of RA pathogenesis may involve the upper respiratory tract.
Keywords: epidemiology; pharyngitis; rheumatoid arthritis; sinusitis; smoking.
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