title: Vitamin D status and its associations with disease activity and severity in African Americans with recent-onset rheumatoid arthritis.
abstract: OBJECTIVE
  To examine the prevalence of vitamin D insufficiency and the associations of vitamin D concentration with disease status in African Americans with rheumatoid arthritis (RA).
  
  
  METHODS
  Study participants (n = 266) were enrolled in the Consortium for the Longitudinal Evaluation of African Americans with Early RA (CLEAR) Registry. The vitamin 25(OH)-D was measured on baseline plasma, and associations of 25(OH)-D with disease status (baseline and at 3 years' disease duration) were examined using univariate and multivariate regression.
  
  
  RESULTS
  The prevalence of 25(OH)-D insufficiency (<or= 37.5 nmol/l or 15 ng/ml) was 50%, with the highest prevalence in winter. In unadjusted analyses, vitamin D concentrations were inversely associated with baseline pain (p = 0.04), swollen joints (p = 0.04), and Disease Activity Score (DAS28, p = 0.05) but not with measures at 3 years' disease duration. There were no multivariate associations of 25(OH)-D with any disease measures at baseline or at 3 years, with the exception of a positive borderline association with rheumatoid factor positivity at enrollment (p = 0.05).
  
  
  CONCLUSIONS
  Vitamin D insufficiency is common in African Americans with recent-onset RA. Unadjusted associations of circulating vitamin D with baseline pain, swollen joints, and DAS28 were explained by differences in season, age, and gender and were not significant in multivariate analyses. In contrast to reports of Northern Europeans with early inflammatory arthritis, there are not strong associations of 25(OH)-D concentration with symptoms or disease severity in African Americans with RA.
authors.affiliation: University of Nebraska Medical Center, Nebraska Arthritis Outcomes Research Center (NAORC), Omaha Veterans Affairs Medical Center, Omaha, Nebraska 68198-6270, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Craig
authors.forename: Fang
authors.initials: F
authors.lastname: Yu
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Curtis
authors.forename: Graciela S
authors.initials: GS
authors.lastname: Alarcón
authors.forename: Doyt L
authors.initials: DL
authors.lastname: Conn
authors.forename: Beth
authors.initials: B
authors.lastname: Jonas
authors.forename: Leigh F
authors.initials: LF
authors.lastname: Callahan
authors.forename: Edwin A
authors.initials: EA
authors.lastname: Smith
authors.forename: Larry W
authors.initials: LW
authors.lastname: Moreland
authors.forename: S Louis
authors.initials: SL
authors.lastname: Bridges
authors.forename: Ted R
authors.initials: TR
authors.lastname: Mikuls
mesh_terms: D000328:Adult; D001741:Black or African American; D000367:Age Factors; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000208:ethnology*; D015897:Comorbidity; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D015995:Prevalence; D012621:Seasons; D012720:Severity of Illness Index; D014481:United States / Q000208:ethnology; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000208:ethnology*
chemical_list: D014807:Vitamin D