title: Effects of 25-hydroxyvitamin D and vitamin D-binding protein on bone mineral density and disease activity in Malaysian patients with rheumatoid arthritis.
abstract: OBJECTIVE
  Vitamin D3 [25(OH)D] has been shown to be important in bone health and can influence rheumatoid arthritis (RA) disease activity. Vitamin D-binding protein (VDBP) levels vary with race and may modulate 'bioavailable' levels of 25(OH)D. The aim of this study was to explore the relationships between 25(OH)D, VDBP and clinical factors on bone mineral density (BMD) in a group of multi-ethnic Malaysian RA patients and healthy controls.
  
  
  METHODS
  A cross-sectional study of 77 female RA patients and 29 controls was performed. Serum 25(OH)D was measured using the Elecsys®Vitamin D total assay. Serum VDBP was measured using a Quantikine®enzyme-linked immunosorbent assay kit. BMD was assessed using dual-energy X-ray absorptiometry (DXA).
  
  
  RESULTS
  Overall, mean 25(OH)D levels were 42.66 ± 21.75 nmol/L with no significant difference between RA patients and controls. 25(OH)D levels were significantly higher in Chinese, compared to Malay/Indian subjects. In RA patients, menopausal status and body mass index (BMI) were significantly associated with BMD but not 25(OH)D or RA Disease Activity Score of 28 joints (DAS28). There was no significant correlation between 25(OH)D and DAS28, even after correction for menopausal status and BMI. VDBP levels were not significantly different between the races and did not significantly correlate with BMD, 25(OH)D overall, or DAS28 in RA patients.
  
  
  CONCLUSIONS
  In Malaysian RA patients, menopausal status and BMI were more important influences on BMD than 25(OH)D or RA disease activity. The utility of measuring VDBP levels in this population remains uncertain.
authors.affiliation: Pathology Division, School of Medicine, International Medical University, Kuala Lumpur, Malaysia.
authors.forename: Tze Hao
authors.initials: TH
authors.lastname: Wong
authors.affiliation: Internal Medicine Department, School of Medicine, International Medical University, Seremban, Malaysia.
authors.forename: Esha Das
authors.initials: ED
authors.lastname: Gupta
authors.affiliation: Pathology Division, School of Medicine, International Medical University, Kuala Lumpur, Malaysia.
authors.forename: Ammu K
authors.initials: AK
authors.lastname: Radhakrishnan
authors.affiliation: Internal Medicine Department, Hospital Tuanku Jaafar, Seremban, Malaysia.
authors.forename: Suk Chyn
authors.initials: SC
authors.lastname: Gun
authors.affiliation: Internal Medicine Department, Hospital Tuanku Jaafar, Seremban, Malaysia.
authors.forename: Gandhi
authors.initials: G
authors.lastname: Chembalingam
authors.affiliation: Department of Medicine, Subang Jaya Medical Centre, Subang Jaya, Malaysia.
authors.forename: Swan Sim
authors.initials: SS
authors.lastname: Yeap
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000000981:diagnostic imaging / Q000208:ethnology / Q000473:pathology*; D044466:Asian People; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D015519:Bone Density; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008296:Malaysia; D008593:Menopause / Q000097:blood / Q000208:ethnology; D008875:Middle Aged; D012720:Severity of Illness Index; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014809:Vitamin D-Binding Protein / Q000097:blood*
chemical_list: D015415:Biomarkers; D014809:Vitamin D-Binding Protein; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-hydroxyvitamin D3; Asian; DAS28; rheumatoid arthritis; vitamin D binding protein