title: Effect of immobilization on vitamin D status and bone mass in chronically hospitalized disabled stroke patients.
abstract: OBJECTIVE
  To assess the influence of immobilization upon vitamin D status and bone mass in chronically hospitalized, disabled, elderly patients following stroke.
  
  
  METHODS
  cross-sectional study.
  
  
  METHODS
  Department of geriatric neurology in a Japanese hospital.
  
  
  METHODS
  129 chronically hospitalized, disabled, elderly stroke patients and 28 age-matched controls.
  
  
  RESULTS
  We observed a deficiency of both 1,25-dihydroxyvitamin D (1,25-[OH]2D; 24.3 pg/ml) and 25-hydroxyvitamin D concentrations (25-OHD; 11.7 ng/ml) in stroke patients compared with controls. A high serum ionized calcium (mean; 2.648 mEq/l) was an independent determinant of the Barthel index (66) and 1,25-[OH]2D. When the patients were categorized into three groups by 25-OHD level (deficient, insufficient and sufficient), there was no difference in the mean 1,25-[OH]2D levels. Parathyroid hormone levels were normal or low and did not correlate with 25-OHD. Serum bone turnover variables and bone mineral density (BMD) of the second metacarpal in patients were significantly decreased compared to control subjects. Independent determinants of BMD included Barthel index, 25-OHD and 1,25-[OH]2D.
  
  
  CONCLUSIONS
  1,25-[OH]2D deficiency in immobilized stroke patients is not caused by substrate (25-OHD) deficiency but by hypercalcaemia. Immobilization-induced hypercalcaemia may inhibit parathyroid hormone secretion and thus 1,25-[OH]2D production, resulting in decreased BMD. Immobilization itself also may be responsible for decreased BMD. Exogenous 1,25-[OH]2D (calcitriol) rather than dietary vitamin D supplementation may be required in disabled elderly stroke patients who have a deficiency of 1,25-[OH]2D in order to prevent hip fractures, which frequently occur in this population.
authors.affiliation: Department of Neurology, Futase Social Insurance Hospital, Iizuka, Japan. y-sato@ktarn.or.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Sato
authors.forename: H
authors.initials: H
authors.lastname: Kuno
authors.forename: T
authors.initials: T
authors.lastname: Asoh
authors.forename: Y
authors.initials: Y
authors.lastname: Honda
authors.forename: K
authors.initials: K
authors.lastname: Oizumi
mesh_terms: D000368:Aged; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000503:physiopathology; D002118:Calcium / Q000097:blood; D002561:Cerebrovascular Disorders / Q000503:physiopathology* / Q000534:rehabilitation; D003430:Cross-Sectional Studies; D006233:Persons with Disabilities; D005260:Female; D006760:Hospitalization; D006801:Humans; D007103:Immobilization / Q000502:physiology*; D007564:Japan; D008134:Long-Term Care; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D012016:Reference Values; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000503:physiopathology* / Q000534:rehabilitation
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium