title: Determinants and effects of vitamin D supplementation on serum 25-hydroxy-vitamin D levels in patients with rheumatoid arthritis.
abstract: OBJECTIVE
  Osteoporosis (OP) and increased risk of fracture are relevant features in patients with rheumatoid arthritis (RA). Low levels of serum vitamin D are frequently reported and correlate with a higher RA activity. This study evaluated factors related with the prescription of vitamin D supplements in RA patients and variables influencing the achievement of adequate vitamin D levels.
  
  
  METHODS
  Study population was made up by 1168 consecutive RA patients from 22 Italian rheumatology centers. Demographic and clinical variables data were collected and 25OH serum vitamin D was measured in all patients. Insufficient serum 25OH vitamin D levels were defined as values lower than 20 ng/mL.
  
  
  RESULTS
  The majority of patients (56.0%) was not taking vitamin D supplements. Among the 514 supplemented patients, 196 (38.1%) were taking insufficient dosages (≤440 IU/day). Variables related with the prescription of supplements were older age, female sex, previous bone density assessment and OP diagnosis. Among the 318 patients using daily supplements ≥800 IU, 88 patients (27.7%) did not reach adequate levels of vitamin D. In these patients a higher HAQ score (OR for 1 point=1.62, 95% CI: 1.06-2.49; p=0.03) and poor sun exposure (OR=2.38, 95% CI: 1.05-5.55; p=0.04) were predictors of vitamin D insufficiency.
  
  
  CONCLUSIONS
  Vitamin D deficiency is common in patients with RA, even in patients who are regularly using supplements. Vitamin D supplementation is often ineffective even at the recommended dose of 800 IU/day in more disabled patients.
authors: Rheumatology Unit, Istituto Ortopedico Gaetano Pini, Milano, Italy. varenna@gpini.it
authors: Massimo
authors: M
authors: Varenna
authors: Maria
authors: M
authors: Manara
authors: Francesco P
authors: FP
authors: Cantatore
authors: Antonio
authors: A
authors: Del Puente
authors: Ombretta
authors: O
authors: Di Munno
authors: Nazzarena
authors: N
authors: Malavolta
authors: Giovanni
authors: G
authors: Minisola
authors: Silvano
authors: S
authors: Adami
authors: Luigi
authors: L
authors: Sinigaglia
authors: Maurizio
authors: M
authors: Rossini
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology*; D015415:Biomarkers / Q000097:blood; D019587:Dietary Supplements; D005260:Female; D019538:Health Care Surveys; D006801:Humans; D007558:Italy / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy* / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D014807:Vitamin D; C104450:25-hydroxyvitamin D