Effect of oral versus intramuscular Vitamin D replacement in apparently healthy adults with Vitamin D deficiency

Context: A number of controversies exist regarding appropriate treatment strategy for Vitamin D deficiency. Aims: The aim of this study was to investigate the efficacy of equivalent doses of oral cholecalciferol (60,000 IU weekly for 5 weeks) versus intramuscular (IM) cholecalciferol (300,000 IU) in correcting Vitamin D deficiency in apparently healthy volunteers working in a hospital. Settings and Design: Prospective randomized open-label single institution study. Subjects and Methods: This study enrolled 40 apparently healthy adults with Vitamin D deficiency into 2 arms. The oral cholecalciferol group (n = 20) received oral cholecalciferol 60,000 IU weekly for 5 weeks while the IM cholecalciferol group (n = 20) received a single injection of cholecalciferol 300,000 IU. The main outcome measure was serum 25-hydroxyvitamin D (25OHD) levels at baseline, 6 and 12 weeks after the intervention. Statistical Analysis Used: Differences in serum 25OHD and other biochemical parameters at baseline and follow-up were analyzed using general linear model. Results: Mean 25OHD level at baseline was 5.99 ± 1.07 ng/mL and 7.40 ± 1.13 ng/mL (P = 0.332) in the oral cholecalciferol and IM cholecalciferol group, respectively. In the oral cholecalciferol group, serum 25OHD level was 20.20 ± 1.65 ng/mL at 6 weeks and 16.66 ± 1.36 ng/mL at 12 weeks. The corresponding serum 25OHD levels in the IM cholecalciferol group were 20.74 ± 1.81 ng/mL and 25.46 ± 1.37 ng/mL at 6 and 12 weeks, respectively. At 12 weeks, the mean 25OHD levels in IM cholecalciferol group was higher as compared to the oral cholecalciferol group (25.46 ± 1.37 vs. 16.66 ± 1.36 ng/mL; P< 0.001). Conclusions: Both oral and IM routes are effective for the treatment of Vitamin D deficiency. 25-hydroxyvitamin D levels in the IM cholecalciferol group showed a sustained increase from baseline.