title: Smoking, rheumatoid factor isotypes and severity of rheumatoid arthritis.
abstract: OBJECTIVE
  Smokers have an increased incidence of rheumatoid factor (RF) and rheumatoid arthritis (RA) and one report has also indicated that smoking may also adversely influence the severity of RA.
  
  
  METHODS
  Sixty-three women with advanced RA answered a structured questionnaire that included detailed information about their smoking history. The women were also evaluated clinically and radiologically.
  
  
  RESULTS
  Heavy smoking (>/= 20 pack-yr) was associated with rheumatoid nodules (P: = 0.01), a higher HAQ score (P: = 0.002) and a lower grip strength (P: = 0.01). Smoking was also associated with more radiological joint damage (P: = 0.02). A positive correlation was observed between smoking and RF levels, in particular IgA RF and a combined elevation of IgM and IgA RF.
  
  
  CONCLUSIONS
  Smoking has an adverse effect on disease progression in patients with RA. An association was also observed between smoking and those RF types that predispose to RA and have the highest diagnostic specificity for this disease.
authors.affiliation: Department of Immunology and. Radiology, Landspítalinn, University of Iceland, Iceland.
authors.forename: B
authors.initials: B
authors.lastname: Masdottir
authors.forename: T
authors.initials: T
authors.lastname: Jónsson
authors.forename: V
authors.initials: V
authors.lastname: Manfredsdottir
authors.forename: A
authors.initials: A
authors.lastname: Víkingsson
authors.forename: A
authors.initials: A
authors.lastname: Brekkan
authors.forename: H
authors.initials: H
authors.lastname: Valdimarsson
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000453:epidemiology* / Q000276:immunology*; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood*; D015994:Incidence; D008875:Middle Aged; D011379:Prognosis; D012217:Rheumatoid Factor / Q000276:immunology*; D012720:Severity of Illness Index; D012907:Smoking / Q000453:epidemiology*
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012217:Rheumatoid Factor