Background: Vitamin D deficiency is widely prevalent in India and subjects who have almost no exposure to sunlight are severely deficient. Daily oral doses of cholecalciferol (vitamin D3) are costly as compared to stoss doses and further, take a long time for the serum levels to reach a plateau. Compliance to supplementation may also be better if a regimen involves single oral doses of vitamin D at specified intervals rather than daily doses. Evidence-based guidelines regarding the dosing and the frequency of dosing for prophylactic intermittent supplementation (stoss doses) in severely-deficient subjects are few.
Materials and methods: In a prospective intervention study, we serially assessed 30 asymptomatic healthy medical staff for serum 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH); (a) at baseline; (b) monthly for 3 months after single oral 60,000 units (U) cholecalciferol; (c) monthly for 3 months after 120,000 (or 180,000 for those with elevated alkaline phosphatase) U cholecalciferol; and, (d) subsequently, at 3 months after a repeat dose of 60,000 U cholecalciferol by repeated measures analysis of variance.
Results: The baseline serum 25(OH)D was 7.1 ± 5.4 ng/mL (< 10 ng/mL in 85% subjects) which increased to 18.7 ± 8.9 ng/mL at 1 month after 60,000 U of cholecalciferol (P < 0.001) and decreased to 11.1 ± 5.3 ng/mL by the 3 rd month. The higher dose of 120,000 (or 180,000) U increased mean 25(OH)D to 28.9 ± 9.9 ng/mL at the end of 1 st month, declining to 17.9 ± 4.9 ng/mL (P < 0.001) at 3 months. With the subsequent 60,000 U the serum 25(OH)D was 18.4 ± 3.9 ng/mL at 3 months. PTH showed a corresponding negative trend. No hypercalcemia was observed.
Conclusions: Vitamin D deficiency is highly prevalent amongst medical staff in Northern India. An initial dose of 120,000-180,000 U of cholecalciferol is required to elevate 25(OH)D out of the deficiency range. Maintenance dose is needed at 2 months.