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