title: Efficacy of different doses and time intervals of oral vitamin D supplementation with or without calcium in elderly nursing home residents.
abstract: The effect of equivalent oral doses of vitamin D3 600 IU/day, 4200 IU/week and 18,000 IU/month on vitamin D status was compared in a randomized clinical trial in nursing home residents. A daily dose was more effective than a weekly dose, and a monthly dose was the least effective.
  
  
  BACKGROUND
  It is assumed that equivalent daily, weekly or monthly doses of vitamin D3 equally influence vitamin D status. This was investigated in a randomized clinical trial in nursing home residents.
  
  
  METHODS
  The study was performed in ten nursing homes including 338 subjects (76 male and 262 female), with a mean age of 84 (+/- SD 6.3 years). They received oral vitamin D3 either 600 IU/day, or 4200 IU/week, or 18,000 IU/month or placebo. After 4 months, calcium was added during 2 weeks, 320 mg/day or 640 mg/day or placebo.
  
  
  RESULTS
  serum levels of 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH) and bone turnover markers. Statistical approach: linear multilevel analysis.
  
  
  RESULTS
  At baseline, mean serum 25(OH)D was 25.0 nmol/L (SD 10.9), and in 98%, it was lower than 50 nmol/L. After 4 months, mean serum 25(OH)D levels increased to 62.5 nmol/L (after daily vitamin D3 69.9 nmol/L, weekly 67.2 nmol/L and monthly 53.1 nmol/L, P < 0.001 between groups). Median serum PTH levels decreased by 23% (p < 0.001). Bone turnover markers did not decrease. Calcium supplementation had no effect on serum PTH and bone turnover.
  
  
  CONCLUSIONS
  Daily vitamin D was more effective than weekly, and monthly administration was the least effective.
authors.affiliation: Verpleeghuis Marienhave, Warmond, The Netherlands.
authors.forename: V
authors.initials: V
authors.lastname: Chel
authors.forename: H A H
authors.initials: HA
authors.lastname: Wijnhoven
authors.forename: J H
authors.initials: JH
authors.lastname: Smit
authors.forename: M
authors.initials: M
authors.lastname: Ooms
authors.forename: P
authors.initials: P
authors.lastname: Lips
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D050071:Bone Density Conservation Agents / Q000008:administration & dosage*; D001862:Bone Resorption / Q000378:metabolism; D002118:Calcium / Q000008:administration & dosage*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D006707:Homes for the Aged; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000209:etiology*; D008297:Male; D010281:Parathyroid Hormone / Q000378:metabolism; D013223:Statistics as Topic; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000378:metabolism; D014808:Vitamin D Deficiency / Q000150:complications / Q000517:prevention & control*
chemical_list: D050071:Bone Density Conservation Agents; C470125:PTH protein, human; D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002118:Calcium