Small airways function in nonsmokers with rheumatoid arthritis

Abstract

To evaluate the possible relationship between rheumatoid arthritis (RA) and airways dysfunction independent of cigarette smoking, we studied 19 lifetime nonsmokers with RA and 47 healthy nonsmokers. Ten tests of small airways function were administered to the subjects. In addition, diffusing capacity and static lung compliance were measured, and upstream airway conductance at mid-to-low lung volumes was calculated. Mean values were not significantly lower in the RA group than in the control group in any of the tests of small airways function. Three of the 19 (16%) patients with RA versus 15 of the 47 (32%) control subjects had abnormal findings on greater than 2 tests of small airways function (P greater than 0.1). Although mean diffusing capacity and static lung compliance were both within normal limits in each group, the former tended to be lower, while the latter was significantly lower, in the RA subjects. We conclude that airways dysfunction in RA, if present, is probably related to factors other than the underlying disease; if an association between RA and small airways abnormality is present in some patients, its prevalence is too small to have been detected in our sample.