A case–control study examining the role of physical trauma in the onset of rheumatoid arthritis

Objective. To investigate whether physical trauma may precipitate the onset of rheumatoid arthritis (RA). Method. In a case-control study comparing RA out-patients with controls attending non-rheumatology out-patient clinics, 262 patients and 262 age- and sex-matched controls completed a postal questionnaire or were interviewed about any physical trauma in the 6 months before the onset of their symptoms. Results. Fifty-five (21%) of the RA patients reported significant physical trauma in the 6 months before the onset of their disease, compared with only 17 (6.5%) of the controls (P < 0.00001). A preceding history of physical trauma was significantly more common in RA patients who were seronegative for rheumatoid factor (P = 0.03), but was not significantly associated with sex (P = 0.78), age (P = 0.64), a family history of RA (P = 0.07) or type of occupation, defined as manual or sedentary (P = 0.6). Conclusion. Physical trauma in the preceding 6 months is significantly associated with the onset of RA.