title: Prevalence and impact of vitamin D insufficiency in southern Chinese adults.
abstract: BACKGROUND
  Vitamin D is a vital element for bone health but the problem of vitamin D deficiency is underestimated in Hong Kong.
  
  
  METHODS
  Serum 25(OH)D and parathyroid hormone (PTH) levels were evaluated in 382 community dwelling Chinese adults >50 years for their relation with bone mineral density (BMD) and risks of osteoporotic fractures and falls.
  
  
  RESULTS
  The mean age of the subjects was 69 +/- 9 years. The mean 25(OH)D level was 28.3 +/- 10.8 ng/ml with 62.8% of the subjects having levels <30 ng/ml. 6.3% of the subjects had elevated PTH levels. A curvilinear relation between serum PTH and 25(OH)D was found, with PTH starting to increase when 25(OH)D level fell below 30 ng/ml (r = -0.233, p < 0.05). Although subjects with vitamin D <30 ng/ml had significantly lower BMD, only sex, age and PTH but not 25(OH)D were predictors of BMD at the spine and hip. Subjects with elevated PTH levels had a 2.92-fold increased risk of falls and 2.94-fold increased risk of fractures at the hip and spine.
  
  
  CONCLUSIONS
  Vitamin D insufficiency and its complication of secondary hyperparathyroidism is common even in subtropical region and is an important risk factor for low bone mass, falls and fractures.
authors.affiliation: Department of Medicine, Pamela Youde Nethasole Eastern Hospital, The University of Hong Kong, Hong Kong, China.
authors.forename: W Z M
authors.initials: WZ
authors.lastname: Wat
authors.forename: J Y Y
authors.initials: JY
authors.lastname: Leung
authors.forename: S
authors.initials: S
authors.lastname: Tam
authors.forename: A W C
authors.initials: AW
authors.lastname: Kung
mesh_terms: D000368:Aged; D015519:Bone Density; D002681:China; D005260:Female; D050723:Fractures, Bone / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D006962:Hyperparathyroidism, Secondary; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000150:complications / Q000503:physiopathology; D010281:Parathyroid Hormone / Q000097:blood; D015995:Prevalence; D013261:Sterols / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology*
chemical_list: C470125:PTH protein, human; D010281:Parathyroid Hormone; D013261:Sterols