Abstract / Summary
Objective We examined associations of post‐traumatic stress disorder (PTSD) and other mental health disorders (OMH) with rheumatoid arthritis (RA), accounting for effects of smoking. Methods We conducted a matched case‐control study, identifying incident RA cases and controls using national Veteran Health Administration data (2006‐2019). PTSD/OMH exposures prior to RA diagnosis were identified using administrative/diagnostic codes. Conditional logistic regression examined associations of RA (vs. no‐RA) with PTSD (±OMH) and OMH. Relative Excess Risk of Interaction was calculated between OMH/PTSD and smoking using standard multivariable logistic regression with standard errors clustered within match groups stratified by ever/never smoking. Analyses were repeated excluding individuals without a visit in the previous year. Results A total of 357,361 Veterans (mean age 53 years, 87% male, 70% ever smoked) were studied. Both PTSD (19% vs. 13%) and OMH (31% vs. 26%) were more frequent in RA than controls. Multivariable analyses demonstrated associations of PTSD and OMH with RA with evidence of PTSD/OMH‐smoking interactions; associations were stronger in never (aORs 1.54/1.40, respectively) vs. ever smokers (aORs 1.20/1.08). Excluding individuals without a healthcare visit, PTSD and OMH remained associated with seronegative RA in ever (aOR 1.17; 95% CI 1.09‐1.26 and aOR 1.14; 95% CI 1.06‐1.21) and never smokers (aOR 1.37; 95% CI 1.16‐1.62 and aOR 1.27; 95% CI 1.10‐1.47); similar associations of PTSD/OMH with seropositive RA were not observed. Conclusion This study demonstrates that the relationships of PTSD (and OMH) with RA differ by smoking status. The strongest associations between PTSD/OMH and incident RA were among never smokers and in seronegative disease.