title: Vitamin D serum level, disease activity and functional ability in different rheumatic patients.
abstract: BACKGROUND
  The aim of the study was to determine the serum vitamin D levels in patients with psoriatic arthritis (PsA) and compare it with patients with rheumatoid arthritis (RA) and with osteoarthritis (OA), as well as to explore the relationship of the vitamin D level with indices of disease activity and functional ability in a real-life setting in a South-European country.
  
  
  METHODS
  In a cross-sectional study, 120 adult patients with established diagnosis of PsA, RA and OA were consecutively enrolled. Serum 25-hydroxyvitamin D and intact parathyroid hormone were determined. Parameters of disease activity and functional ability were obtained using standard instruments.
  
  
  RESULTS
  Serum vitamin D insufficiency (≤ 75 nmol/L) was found in 74% of patients with PsA, 94% patients with RA and 97% of patients with OA, whereas vitamin D deficiency (≤ 25 nmol/L) was found in 13% of patients with PsA, 39% of patients with RA and in 38% of patients with OA. Compared with RA, patients with PsA had significantly higher serum vitamin D (P = 0.002), and when controlling for age and gender, their serum vitamin D level was significantly associated with disease activity and functional activity.
  
  
  CONCLUSIONS
  In the group of rheumatic patients, a high prevalence of serum vitamin D insufficiency/deficiency was found regardless of the type of arthritis. Patients with PsA might have higher levels of vitamin D than patients with RA, and this was associated with disease activity and functional ability. The results of this study indicate that prophylactic supplementation with vitamin D might be recommended for all rheumatic patients.
authors.affiliation: University Department of Rheumatology, Physical and Rehabilitation Medicine (SG, FG, HSK), Sestre Milosrdnice Clinical Hospital Centre, School of Medicine, Zagreb, Croatia; University Department of Rheumatic Diseases and Rehabilitation (DBN), Clinical Hospital Centre, School of Medicine, Zagreb, Croatia; Department of Clinical Immunology and Rheumatology (BA, MB), Clinical Hospital Centre, School of Medicine, Zagreb, Croatia; Department of Physical and Rehabilitation Medicine (DB), Clinical Hospital Dubrava, Zagreb, Croatia; Clinical Institute of Chemistry (ATK), Sestre Milosrdnice Clinical Hospital Centre, Zagreb, Croatia; and Institute for Medical Research and Occupational Health (SC), Zagreb, Croatia.
authors.forename: Simeon
authors.initials: S
authors.lastname: Grazio
authors.forename: Đurđica B
authors.initials: ĐB
authors.lastname: Naglić
authors.forename: Branimir
authors.initials: B
authors.lastname: Anić
authors.forename: Frane
authors.initials: F
authors.lastname: Grubišić
authors.forename: Dubravka
authors.initials: D
authors.lastname: Bobek
authors.forename: Marija
authors.initials: M
authors.lastname: Bakula
authors.forename: Hana S
authors.initials: HS
authors.lastname: Kavanagh
authors.forename: Andrea T
authors.initials: AT
authors.lastname: Kuna
authors.forename: Selma
authors.initials: S
authors.lastname: Cvijetić
mesh_terms: D000368:Aged; D015535:Arthritis, Psoriatic / Q000097:blood* / Q000453:epidemiology; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000453:epidemiology; D017523:Croatia / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000097:blood* / Q000453:epidemiology; D010281:Parathyroid Hormone / Q000097:blood; D015995:Prevalence; D012720:Severity of Illness Index; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D