title: Vitamin D status and parathyroid hormone in a urban population in Vietnam.
abstract: In this cross-sectional study in Vietnam, the prevalence of vitamin D insufficiency was 46% in adult women and 20% in adult men. There was a linear inverse relationship between serum 25(OH)D and PTH concentrations, but there was no threshold of 25(OH)D at which PTH levels plateaued.
  
  
  BACKGROUND
  Vitamin D insufficiency is adversely associated with health outcomes. Vitamin D status in Asian populations is not well documented. This study sought to assess vitamin D status and its relationship to parathyroid hormone in a Vietnamese population.
  
  
  METHODS
  This cross-sectional study involved 205 men and 432 women aged 18-87 years, who were randomly sampled from various districts in Ho Chi Minh City (Vietnam) according to a proportional sampling scheme. Serum concentration of 25(OH)D and PTH were measured by the Electrochemiluminescence immunoassay on the Roche Elecsys 10100/201 system (Roche Diagnosis Elecsys). Vitamin D insufficiency was quantified as serum 25(OH)D levels below 30 ng/ml (75 nmol/L).
  
  
  RESULTS
  The average age for men and women was 43.8 ± 18.4 years (mean ± SD) and 47.7 ± 17.1 years, respectively. The mean 25(OH)D concentration in men (36.8 ± 10.2 ng/mL) was significantly higher than in women (30.1 ± 5.9; P < 0.0001). The prevalence of vitamin D insufficiency in men was 20% (41/205) which was significantly lower than in women (46%, 199/432). Age, height and weight were independent predictors of 25(OH)D concentrations, and the three factors explained 15% and 5% of variance in 25(OH)D in men and women, respectively. There was a linear inverse relationship between serum 25(OH)D and PTH concentrations, but there was no threshold of 25(OH)D at which PTH levels plateaued.
  
  
  CONCLUSIONS
  These data show that vitamin D insufficiency is common even in tropical region, and that women had a greater risk of vitamin D insufficiency than men. These data suggest that an elevation in PTH cannot be used as a marker for vitamin D deficiency.
authors.affiliation: Department of Internal Medicine, Pham Ngoc Thach University of Medicine, Thanh Thai Street, District 10, Ho Chi Minh City, Vietnam. thuclanhopham@pnt.edu.vn
authors.forename: L T
authors.initials: LT
authors.lastname: Ho-Pham
authors.forename: N D
authors.initials: ND
authors.lastname: Nguyen
authors.forename: T Q
authors.initials: TQ
authors.lastname: Lai
authors.forename: J A
authors.initials: JA
authors.lastname: Eisman
authors.forename: T V
authors.initials: TV
authors.lastname: Nguyen
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D017678:Sex Distribution; D014504:Urban Health / Q000706:statistics & numerical data*; D014744:Vietnam / Q000453:epidemiology; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D014807:Vitamin D