title: First-degree relatives of patients with rheumatoid arthritis exhibit high prevalence of joint symptoms.
abstract: OBJECTIVE
  The preclinical period of rheumatoid arthritis (RA) is characterized by the presence of autoantibodies such as anticitrullinated protein antibodies (ACPA) and rheumatoid factor (RF). Little is known about the joint symptom profile preceding onset of RA, and whether symptoms are associated with RA autoantibodies. Because first-degree relatives (FDR) of North American Native (NAN) RA probands exhibit multiple risk factors for development of future RA, we investigated the prevalence of joint symptoms in this high-risk population.
  
  
  METHODS
  We studied 306 FDR of NAN patients with RA, 323 NAN controls (NC), and 293 white controls (WC) having no family history of autoimmune diseases. Study subjects completed a questionnaire that asked whether they had pain, swelling, or morning stiffness in their hand joints, or in other joints. Serum samples were gathered at the same time and tested for the presence of ACPA, RF, and high-sensitivity C-reactive protein levels.
  
  
  RESULTS
  In all cases, FDR were significantly more likely to report experiencing joint symptoms compared to the 2 control groups. FDR also exhibited a significantly higher prevalence of RA autoantibodies than the control groups. There were modest trends for joint symptoms to associate with RA autoantibodies, and individuals who were both ACPA-positive and RF-positive had the highest prevalence of joint symptoms.
  
  
  CONCLUSIONS
  FDR of NAN patients with RA have a higher prevalence of joint symptoms compared to individuals with no family history of autoimmune disease. This finding is only partially explained by a high prevalence of RA autoantibodies in the FDR.
authors.affiliation: Arthritis Centre, University of Manitoba, Manitoba, Canada.
authors.forename: Irene
authors.initials: I
authors.lastname: Smolik
authors.forename: David B
authors.initials: DB
authors.lastname: Robinson
authors.forename: Charles N
authors.initials: CN
authors.lastname: Bernstein
authors.forename: Hani S
authors.initials: HS
authors.lastname: El-Gabalawy
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D001323:Autoantibodies / Q000097:blood; D002097:C-Reactive Protein; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007596:Joints / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D062706:Prodromal Symptoms; D012217:Rheumatoid Factor / Q000097:blood; D011795:Surveys and Questionnaires
chemical_list: D001323:Autoantibodies; D002097:C-Reactive Protein; D012217:Rheumatoid Factor
keywords: ANTICITRULLINATED PROTEIN ANTIBODIES; FIRST-DEGREE RELATIVE; JOINT SYMPTOMS; NORTH AMERICAN NATIVE; PREVALENCE; RHEUMATOID ARTHRITIS