title: Effect of oral cholecalciferol 2,000 versus 5,000 IU on serum vitamin D, PTH, bone and muscle strength in patients with vitamin D deficiency.
abstract: Treatment of vitamin D deficiency for 3 months with oral cholecalciferol 5,000 IU daily was more effective than 2,000 IU daily in achieving optimal serum 25-hydroxyvitamin D (25OHD) concentrations. Optimal 25OHD serum level calculated to be 63.8 nmol/L. All parameters of muscle strength improved following administration of cholecalciferol for 3 months.
  
  
  BACKGROUND
  The aim of this study was to determine the optimal dose of cholecalciferol required to achieve target serum 25OHD level ≥ 75 nmol/L and its relationship to both bone turnover and muscle strength.
  
  
  METHODS
  Thirty deficient patients (serum 25OHD ≤ 50 nmol/L) were randomly assigned into two groups-i.e. 2,000 and 5,000 IU/day. Data were collected at baseline, at 2 and 3 months post-therapy: (a) clinical demographics, (b) dietary calcium recall, (c) physical tests of muscle function and (d) biochemistry. Statistical analysis used paired student t test and analysis of variance. Regression analysis was used to determine relationship between serum 25OHD and parathyroid hormone (PTH).
  
  
  RESULTS
  Twenty-six (87%) patients completed 3 months of therapy. The percent increase in serum 25OHD (compared to baseline) was 82.7% in 2,000-IU group and 219.5% in 5,000-IU group. All participants (100%) achieved a serum 25OHD concentration >50 nmol/L; only 5 subjects (45.4%) in 2,000-IU group compared to 14 subjects (93.3%) in 5,000-IU group achieved final 25OHD concentration ≥ 75 nmol/L (p < 0.01). In the regression analysis, the reflexion point at which the PTH level increased above the normal range was calculated to be 63.8 nmol/L 25OHD. All parameters of muscle strength showed trends in improvements following the administration of both the 2,000 and 5,000 IU doses. No patient reported untoward side effects and no patient developed hypercalcaemia.
  
  
  CONCLUSIONS
  Treatment for 3 months with oral cholecalciferol 5,000 IU daily may be more effective than 2,000 IU daily in achieving optimal serum 25OHD concentrations in vitamin D-deficient patients.
authors.affiliation: Department Endocrinology, St George Hospital, Level 3 Prichard Wing, Gray street, Kogarah, NSW 2211, Australia. terrydiamond@optusnet.com.au
authors.forename: T
authors.initials: T
authors.lastname: Diamond
authors.forename: Y K
authors.initials: YK
authors.lastname: Wong
authors.forename: T
authors.initials: T
authors.lastname: Golombick
mesh_terms: D000284:Administration, Oral; D000328:Adult; D050071:Bone Density Conservation Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D016723:Bone Remodeling / Q000187:drug effects*; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000503:physiopathology; D010281:Parathyroid Hormone / Q000097:blood; D016896:Treatment Outcome; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D050071:Bone Density Conservation Agents; D010281:Parathyroid Hormone; D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D