title: Vitamin D status and its association with mineral and bone disorder in a multi-ethnic chronic kidney disease population.
abstract: BACKGROUND
  Vitamin D deficiency is associated with secondary hyperparathyroidism and mineral and bone disorder (MBD) in chronic kidney disease (CKD). This study aimed to determine the prevalence of vitamin D insufficiency/deficiency, and the association between vitamin D status and MBD in a multi-ethnic CKD population in Southeast Asia.
  
  
  METHODS
  Predialysis CKD patients were included in this cross-sectional study. Patient demographics, medical/medication histories, and laboratory parameters (serum 25-hydroxyvitamin D (25(OH)D), creatinine, phosphate (P), calcium, albumin, and intact-PTH (i-PTH)) were collected and compared among patients with various CKD stages. The association between 25(OH)D and these parameters was determined by multiple linear regression.
  
  
  RESULTS
  A total of 196 patients with mean ± SD eGFR of 26.4 ± 11.2 mL/min/1.73 m2 was included. Vitamin D deficiency (25(OH)D concentration < 15 ng/mL) and insufficiency (25(OH)D concentration 16 - 30 ng/mL) was found in 29.1% and 57.7% of the patients, respectively. Mean ± SD serum 25(OH)D was 20.8 ± 9.3 ng/mL. Female patients had lower vitamin D concentrations than males (16.9 ng/mL vs. 23.9 ng/mL; p < 0.001). Vitamin D levels were also higher in Chinese (22.3 ng/mL) than Malay (17.3 ng/mL) and Indian (13.1 ng/mL) patients (p < 0.05). Nonadjusted analyses showed higher i-PTH concentration in vitamin D deficient patients (p < 0.05).
  
  
  CONCLUSIONS
  Despite being a sun-rich country all year round, the majority (86.8%) of predialysis CKD patients in Singapore have suboptimal vitamin D status. Lower vitamin D concentrations were found in females and in those with darker skin tone. Vitamin D deficient patients also tended to have higher i-PTH levels.
authors.forename: Melissa
authors.initials: M
authors.lastname: Ngai
authors.forename: Valerie
authors.initials: V
authors.lastname: Lin
authors.forename: Hung Chew
authors.initials: HC
authors.lastname: Wong
authors.forename: Anantharaman
authors.initials: A
authors.lastname: Vathsala
authors.forename: Priscilla
authors.initials: P
authors.lastname: How
mesh_terms: D000368:Aged; D002118:Calcium / Q000097:blood; D002681:China / Q000208:ethnology; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000453:epidemiology; D007194:India / Q000208:ethnology; D008296:Malaysia / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D015995:Prevalence; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology*; D012189:Retrospective Studies; D012709:Serum Albumin / Q000032:analysis; D012737:Sex Factors; D012846:Singapore / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology*; D014815:Vitamins
chemical_list: D010281:Parathyroid Hormone; D010710:Phosphates; D012709:Serum Albumin; D014815:Vitamins; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D003404:Creatinine; D002118:Calcium