Comparison of Different Vitamin D Supplementation Regimens in the Management of Hypovitaminosis D among Children Aged 1 to 5 Years: An Observational Study

Background: The management of hypovitaminosis D requires therapeutic supplementation of vitamin D along with calcium. In India, a single oral dose of 600,000 IU vitamin D is commonly prescribed for hypovitaminosis D and rickets, as no standardized national guideline exists. This study aimed to compare the efficacy and safety of three different vitamin D regimens—300,000 IU single dose, 600,000 IU single dose, and 60,000 IU weekly for 10 weeks—in children aged 1 to 5 years with documented hypovitaminosis D. Methods: This observational study included children between 1–5 years diagnosed with hypovitaminosis D. Participants were grouped based on supplementation regimen: (i) 60,000 IU sachet weekly for 10 weeks, (ii) 300,000 IU stat orally, and (iii) 600,000 IU stat orally. Serum vitamin D levels were assessed before and after therapy. Results: All three regimens resulted in significant improvement in serum vitamin D levels. The highest proportion of children achieving sufficiency was observed in the 600,000 IU stat group. However, two cases of hypervitaminosis D occurred in this group. Comparatively, both the 60,000 IU weekly and 300,000 IU stat regimens showed effective correction of deficiency with a safer profile. Conclusion: While all three vitamin D regimens are effective in treating hypovitaminosis D in young children, the 600,000 IU stat regimen is associated with a risk of hypervitaminosis. Therefore, 60,000 IU weekly or 300,000 IU stat dosing may be safer alternatives.