The association of cigarette smoking with disease outcome in patients withearly inflammatory polyarthritis

Objective. Cigarette smoking is known to increase rheumatoid factor (RF) an d nodule formation in patients with rheumatoid arthritis (RA). In this stud y, we examined the influence of smoking on disease outcome at 3 years among patients newly presenting with inflammatory polyarthritis (IP). Methods. We studied 486 patients with IP who were referred to the Norfolk A rthritis Register, of whom 323 (67%) satisfied the American College of Rheu matology 1987 criteria for RA. Smoking status was assessed at baseline. Dis ease outcome was assessed at 3 years, using measures of joint inflammation, functional disability, and radiologic damage. The influence of smoking on disease outcome was explored using logistic regression techniques, with pat ients who had never smoked as the referent group. Results are expressed as odds ratios (ORs), with their 95% confidence inter vals (95% Cls). Results. Current smokers were significantly more likely to be RIF positive at baseline (47%) than were ex-smokers (34%) and never smok ers (31%). After 3 years, rheumatoid nodules were significantly more common in smokers (13%) compared with ex-smokers/never smokers (4%), a relationsh ip which persisted after adjusting for age and sex (OR 4.07, 95% Cl 1.38-12 ). In contrast, after adjusting for age and sex, current smokers had signif icantly fewer swollen joints (OR 0.61, 95% CI 0.37-0.98). However, smoking status had no influence on the development of erosions or functional disabi lity. Conclusion. Despite smokers being more likely to develop nodules and to be RIF positive, current smokers did not have higher levels of radiologic dama ge, and had fewer swollen joints. We hypothesize that this could be due to either the effect of cigarette smoking on the inflammatory response or othe r factors (e.g., reduced physical activity in smokers) which may limit join t inflammation and damage.