title: Systemic sclerosis in Canada's North American Native population: assessment of clinical and serological manifestations.
abstract: OBJECTIVE
  Certain North American Native (NAN) populations are known to have higher rates of systemic sclerosis (SSc) compared to non-NAN; however, little is known of the specific disease characteristics in this population in Canada. This study compares the clinical and serological manifestations of SSc in NAN and white patients.
  
  
  METHODS
  This cross-sectional, multicenter study included subjects enrolled in the Canadian Scleroderma Research Group registry between September 2004 and June 2012. Subjects were evaluated with complete medical histories, physical examinations, and self-questionnaires. Ethnicity was defined by self-report. Disease characteristics were compared between NAN and white patients and multivariate analyses were performed to determine the independent association between ethnicity and various clinical manifestations.
  
  
  RESULTS
  Of 1278 patients, 1038 (81%) were white, 71 (6%) were NAN, and 169 (13%) were classified as non-white/non-NAN. There were important differences between NAN and white subjects with SSc. In multivariate analysis adjusting for socioeconomic differences and smoking status, NAN ethnicity was an independent risk factor for the severity of Raynaud phenomenon and more gastrointestinal symptoms, and was associated with a nonsignificant increase in the presence of digital ulcers.
  
  
  CONCLUSIONS
  NAN patients with SSc have a distinct clinical phenotype. Our study provides a strong rationale to pursue further research into genetic and environmental determinants of SSc.
authors.affiliation: Department of Internal Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Adrienne
authors.initials: A
authors.lastname: Bacher
authors.forename: Shikha
authors.initials: S
authors.lastname: Mittoo
authors.forename: Marie
authors.initials: M
authors.lastname: Hudson
authors.forename: Solène
authors.initials: S
authors.lastname: Tatibouet
authors.forename: Murray
authors.initials: M
authors.lastname: Baron
mesh_terms: D000328:Adult; D000368:Aged; D002170:Canada / Q000208:ethnology; D005260:Female; D006801:Humans; D007198:Indians, North American; D008297:Male; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors; D012595:Scleroderma, Systemic / Q000097:blood / Q000175:diagnosis / Q000208:ethnology*; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D044465:White People
keywords: DISEASE SEVERITY; NORTH AMERICAN NATIVE; SCLERODERMA; SYSTEMIC SCLEROSIS