title: Serum 25-hydroxyvitamin D, bone mineral density, and non-vertebral fracture risk in community-dwelling older men: results from Mr. Os, Hong Kong.
abstract: The study examined vitamin D status in relation to bone mineral density (BMD) and fracture risk in older Chinese men. Vitamin D deficiency was uncommon in this sample. Higher serum vitamin D level was associated with higher baseline BMD, but was not associated with bone loss or fracture risk.
  
  
  OBJECTIVE
  Vitamin D status in relation to bone health and fracture risk in Asian men is unknown. This study examined how vitamin D status was associated with BMD and fracture risk in Chinese men.
  
  
  METHODS
  The study consisted of a cross-sectional and longitudinal design (the 4-year follow-up). Subjects included 939 and 712 men aged 65 year and older for cross-sectional analysis and longitudinal analysis, respectively. Baseline serum 25-hydroxyvitamin D (25OHD) was measured by a competitive radioimmunoassay kit. Baseline and 4-year percentage change in BMD at total hip, spine, and femoral neck was examined by dual-energy X-ray absorptiometry. Data on incident non-vertebral fractures and hip fractures in 4 years were collected. Data were collected for confounding factors: demographics, smoking, alcohol use, body mass index, physical activity, diet, season of blood measurement, and serum parathyroid hormone level. Multivariate regression analyses were performed with adjustments for confounding factors.
  
  
  RESULTS
  A total of 94.1% of this sample had serum 25OHD at 50 nmol/L and over. After adjustment for potential confounding factors, higher serum 25OHD level was associated with higher baseline BMD at all measured sites. No association was observed between serum 25OHD level and percentage change in BMD or risk of non-vertebral fracture or hip fracture after adjustment for confounding factors.
  
  
  CONCLUSIONS
  Vitamin D deficiency was not common in this sample of Chinese men. Higher serum 25OHD level was associated with higher BMD at cross-sectional level. There was no association between serum 25OHD level and bone loss or fracture risk.
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong SAR, People's Republic of China. ruthchansm@cuhk.edu.hk
authors.forename: Ruth
authors.initials: R
authors.lastname: Chan
authors.forename: Cheong Chun Dicken
authors.initials: CC
authors.lastname: Chan
authors.forename: Jean
authors.initials: J
authors.lastname: Woo
authors.forename: Claes
authors.initials: C
authors.lastname: Ohlsson
authors.forename: Dan
authors.initials: D
authors.lastname: Mellström
authors.forename: Timothy
authors.initials: T
authors.lastname: Kwok
authors.forename: Ping Chung
authors.initials: PC
authors.lastname: Leung
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D003430:Cross-Sectional Studies; D050723:Fractures, Bone / Q000209:etiology*; D006723:Hong Kong; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D018570:Risk Assessment; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D