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

To investigate whether physical trauma may precipitate the onset of rheumatoid arthritis (RA).

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.

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).

Physical trauma in the preceding 6 months is significantly associated with the onset of RA.