Background Rheumatoid arthritis (RA) is an inflammatory disease characterized by chronic synovitis and erosive destruction of articular cartilage and bone ultimately leading to joint deformities, disability, loss of quality of life and work loss. There are multiple risk factors, both environmental and genetic, that may predispose an individual to developing RA. Cigarette smoking is the most important risk factor. Citrulline contained within proteins is created post-translationally by the action of the enzyme peptidyl arginine deiminase on the aminoacid arginine. Citrullination takes place in several normal cellular processes, including inflammation, apoptosis, and cellular differentiation. Additionally, tissues involved in inflammation have increased levels of citrullinated proteins. Smoking may lead to increased formation of citrullinated proteins, which in the appropriate genetic background leads to autoimmunity to citrullinated proteins and subsequently the development of clinically apparent RA. This model of RA development is compelling at least in terms of anti-citrullinated peptides antiodies (ACPA) positive RA that occurs in smokers, although the specific anatomic sites and mechanisms by which smoking leads to ACPA generation and RA have yet to be elucidated.
Objectives To evaluate the prevalence of tobacco smokers in different sub-groups of patients with RA. Sub-groups were formed according to the combination of positivity and negativity of ACPA and rheumatoid factor (RF).
Methods We examined patients with rheumatoid arthritis. We performed examination of ACPA and RF at the baseline. We formed 4 sub-groups of patients with rheumatoid arthritis: ACPA positive and RF positive, ACPA positive and RF negative, ACPA negative and RF positive, ACPA negative and RF negative. We collected data from medical history concerning smoking status in each individual patient.
Results The total number of 290 patients with rheumatoid arthritis was examined. There were 50 patients in the sub-group with ACPA positivity and RF positivity, 19 of them were smokers (38%, n=50). There were 13 patients in the sub-group with ACPA positivity and RF negativity, 5 of them were smokers (39%, n=13). There were 97 patients in the sub-group with ACPA negativity and RF positivity, 28 of them were smokers (29%, n=97). There were 130 patients in the sub-group with ACPA negativity and RF negativity, 28 of them were smokers (21%, n=130. The highest prevalence of smokers was in the sub-group of patients with ACPA and RF positive rheumatoid arthritis (39%) and ACPA positive and RF negative rheumatoid arthritis (38%). The prevalence of smokers in ACPA negative sub-groups of patients with rheumatoid arthritis is significantly lower.
Conclusions We confirmed that prevalence of smokers is significantly higher in the sub-group of patients with ACPA positive rheumatoid arthritis than in the sub-group with ACPA negative rheumatoid arthritis. Quitting smoking is highly recommended especially to these patients in order to achieve a favorable effect on the course of the disease.
Maria J H de Hair, et al. Smoking and overweight determine the likehood of developing rheumatoid arthritis. Ann Rheum Dis 2013;72(10):1654–1658.
Disclosure of Interest None declared