Comparison of the Effect of High-Dose Versus the Recommended Dose of Vitamin D Supplementation on Serum 25(Oh)D Levels in Osteopenic Women Over 50 Years Old



A Bagheri ALIREZA ; Hr Aghaei Meybodi Hamidreza REZA ; A Soltani AKBAR ; Mr Mohajeritehrani Mohammad REZA ; R Heshmat RAMIN ; Ba Larijani Bagher A
Source: Iranian Journal of Diabetes and Metabolism Published:2025

Abstract

Background: Vitamin D (vitD) deficiency is common in Iran. Although there are several studies on therapeutic doses of vitD, the optimal dose is to be evolved. we compared the effects of high dose supplemental vitamin D versus its recommended dose on the serum level of 25(OH)D. Methods: This clinical trial was performed at Endocrine & Metabolism Research Institute in Shariati Hospital, Tehran, Iran within 2008-2009. The subjects were osteopenic women older than 50 years who had been referred to Bone Densitometry laboratory. They were received either (group P) 50000u vitD3 weekly for 3 months then monthly for another 9 months, or (group M) 800u vitD3 daily for one year. 1000 mg calcium carbonate was given to both groups. Serum 25(OH)D, calcium, phosphorus, and PTH was checked at base, 3rd, 6th and 12th month. 24h Urine for calcium was collected before and at the end of trial. Result: Serum 25(OH)D level was significantly higher in group P at 3rd month (P< 0.05), but it gradually declined and there was not statistically difference to group M. PTH decreased in both groups. Urine calcium to creatinine ratio did not rise in both groups. Conclusion: vitD supplement at doses of 50000u weekly for 3 months then monthly for another 9 months as compare to 800u vitD3 daily for one year increases serum 25(OH)D at higher level without causing hypercalcemia and hypercalciuria, but it seems that more frequent doses in monthly period would be required to maintain the optimal 25(OH)D level. © 2025 Elsevier B.V., All rights reserved.