Antecedent tonsillectomy and appendectomy in rheumatoid arthritis.

The prevalence of tonsillectomy and appendectomy was higher in 196 patients with rheumatoid arthritis (RA), prior to the onset of articular disease, than in their spouses and siblings. The estimated increased risk of developing RA with tonsillectomy was 1.5 and 3.5 times, with appendectomy 1.7 and 6.6 times, and with both surgical procedures 2.3 and 6.7 times, using patient-spouse and patient-sibling matched-pair data, respectively. However, only with patient-sibling data did the lower limits of the 95% confidence interval for the risk ratio exceed 1.0. Several hypotheses are offered to explain the possible association between these surgical procedures and RA.