title: Vitamin D and its relationship with markers of bone metabolism in healthy Asian women.
abstract: BACKGROUND
  In this study, we aimed to determine the normal ranges of 25-hydroxy-vitamin D(3) (25-OHD(3)), parathyroid hormone (PTH), and the markers of bone turnover, procollagen type 1 N propeptide (P1NP) and C-terminal cross-linked telopeptide of type 1 collagen (CTX), in normal healthy women in Singapore, and to explore the relationship between vitamin D, PTH, and these markers of bone turnover in the women.
  
  
  METHODS
  One hundred and ninety-seven healthy women, aged 25 to 60, were selected from a hospital staff health screening program; 68% were Chinese, 18% Malay, and 14% Indian. P1NP, CTX, and 25-OHD(3) were measured using the Roche Cobas® electrochemiluminescence immunoassay. Serum PTH was measured using the Siemens ADVIA Centaur® immunoassay.
  
  
  RESULTS
  Sixty-five percent had 25-OHD(3) concentrations <50 nmol/l. Vitamin D insufficiency (25-OHD(3) < 50 nmol/l) was more prevalent in Malays (89%) and Indians (82%) compared to Chinese (56%). There was no correlation between vitamin D and age. PTH positively correlated with age, and Malays and Indians had higher PTH concentrations than Chinese. There was an inverse correlation between PTH and 25-OHD(3), but no threshold of 25-OHD(3) concentrations at which PTH plateaued. The bone turnover markers P1NP and CTX inversely correlated with age but were not different between ethnic groups. CTX and P1NP exhibited good correlation, however, there was no significant correlation between 25-OHD(3) or PTH concentrations and the bone turnover markers P1NP and CTX.
  
  
  CONCLUSIONS
  Healthy women in Singapore have a high prevalence of vitamin D insufficiency. Vitamin D insufficiency was more prevalent in Malays and Indians compared to Chinese.
authors.affiliation: Department of Laboratory Medicine, National University Health System, Singapore. karen.tan@mohh.com.sg
authors.forename: Karen M L
authors.initials: KM
authors.lastname: Tan
authors.forename: Sharon
authors.initials: S
authors.lastname: Saw
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Sethi
mesh_terms: D000328:Adult; D044466:Asian People; D015415:Biomarkers / Q000097:blood*; D001842:Bone and Bones / Q000378:metabolism*; D002112:Calcifediol / Q000097:blood*; D002681:China / Q000208:ethnology; D024042:Collagen Type I / Q000097:blood; D005260:Female; D006801:Humans; D007194:India / Q000208:ethnology; D008296:Malaysia / Q000208:ethnology; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D010455:Peptides / Q000097:blood; D011347:Procollagen / Q000097:blood; D012016:Reference Values; D012846:Singapore / Q000453:epidemiology; D014808:Vitamin D Deficiency / Q000453:epidemiology*; D044465:White People
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D010455:Peptides; D011347:Procollagen; C052929:collagen type I trimeric cross-linked peptide; C047202:procollagen Type I N-terminal peptide; D002112:Calcifediol
keywords: 25-OHD3; CTX; P1NP; PTH; association; healthy Asian women