title: Different risk factors between interstitial lung disease and airway disease in rheumatoid arthritis.
abstract: OBJECTIVE
  To identify clinical and genetic risk factors for interstitial lung disease (ILD) or airway disease (AD) in patients with rheumatoid arthritis (RA) and to evaluate differences between the associations of these factors with ILD and AD.
  
  
  METHODS
  We reviewed high-resolution computed tomography (HRCT) images and clinical data of 356 RA patients obtained at their first visit. The diagnosis of ILD and AD was based on abnormal HRCT findings. Multinomial logistic regression analysis and likelihood ratio tests were performed.
  
  
  RESULTS
  High titers of rheumatoid factor are similarly associated with increased risks of ILD (relative risk ratio, 3.1; p = 0.02) and AD (relative risk ratio, 3.0; p = 0.02). High levels of anti-cyclic citrullinated peptide antibodies were associated strongly with AD (relative risk ratio, 3.8; p = 0.005) and less strongly with ILD (relative risk ratio, 2.7; p = 0.07). Age was the potent risk factor for ILD (relative risk ratio, 4.6; p = 0.003), while that for AD was advanced stage (relative risk ratio, 11.5; p < 0.0005). The carriage of HLA-DRB1*1502 had opposite influences on the two conditions: relative risk ratio = 4.02 for ILD (p = 0.013) and relative risk ratio = 0.15 for AD (p = 0.08). This difference was statistically significant (p = 0.0005). Associations of sex and smoking history with ILD disappeared in the multinomial logistic regression analysis.
  
  
  CONCLUSIONS
  The differential associations of ILD and AD with various clinical and genetic factors suggest that ILD and AD have distinct etiologies in RA.
authors.affiliation: Department of Rheumatology, Clinical Research Center for Rheumatic Disease, NHO Kumamoto Saishunsou National Hospital, 2659 Suya, Kohshi, Kumamoto 861-1196, Japan. moris@saisyunsou1.hosp.go.jp
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Mori
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Koga
authors.forename: Mineharu
authors.initials: M
authors.lastname: Sugimoto
mesh_terms: D000368:Aged; D000906:Antibodies / Q000378:metabolism; D001172:Arthritis, Rheumatoid / Q000150:complications* / Q000235:genetics; D001982:Bronchial Diseases / Q000000981:diagnostic imaging / Q000209:etiology* / Q000235:genetics; D005260:Female; D059811:HLA-DRB1 Chains / Q000235:genetics; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging / Q000209:etiology* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology; D012217:Rheumatoid Factor / Q000378:metabolism; D012307:Risk Factors; D014057:Tomography, X-Ray Computed
chemical_list: D000906:Antibodies; D059811:HLA-DRB1 Chains; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor