Influence of Smoking on Disease Activity and Quality of Life in Patients With Rheumatoid Arthritis: Results From a Swedish Case-Control Study With Longitudinal Follow-Up

ObjectiveInconclusive findings have been reported regarding the influence of smoking on disease outcomes in established rheumatoid arthritis (RA). This study was undertaken to investigate the influence of smoking habits on disease activity and health-related quality of life (HRQoL) in RA patients. MethodsPatients with newly diagnosed RA (n = 1,531) from the population-based case-control Epidemiological Investigation of Rheumatoid Arthritis study were followed up for up to 3 years after recruitment. Using logistic regression models, the risks of unfavorable outcomes in patients with different smoking habits were compared using self-reported swollen and tender joint counts, the Short Form 36 health survey, the Health Assessment Questionnaire, and the Hospital Anxiety and Depression Scale by calculating odds ratios with 95% confidence intervals. ResultsAt 1-year and 3-year follow-up, current smokers reported higher disease activity and lower HRQoL life compared to non-smokers, regarding both physical and mental aspects. Patients who stopped smoking within 1-year post-baseline had less disease activity measured as swollen joint counts at 1-year follow-up compared to those who continued smoking. Patients who stopped smoking after the 1-year follow-up had higher disease activity and lower HRQoL at baseline than smokers who did not quit, and late smoking cessation was not associated with more favorable outcomes compared to continued smoking. ConclusionCurrent smoking is associated with increased disease activity and lower HRQoL among RA patients. Smoking cessation within the first year after baseline appears to have a favorable effect on disease activity.