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

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. 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. 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). 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