Changes in 25-Hydroxyvitamin D3 to oral treatment with vitamin D3 in postmenopausal females with osteoporosis.

SUMMARY

This study reports on oral treatment with different doses of vitamin D3 ranging from 25 to 200 microg in females with 25-hydroxyvitamin D3 levels < 60 nmol/L screened for participation in an osteoporosis trial. A guidance to safely and efficiently achieve 25-hydroxyvitamin D3 levels > 60 nmol/L is presented.

INTRODUCTION

The importance of vitamin D for skeletal health has been implemented in clinical trials in osteoporosis. The threshold of 25-hydroxyvitamin D for inclusion has changed from 30 to 60 nmol/L. This study reports on oral treatment with different doses of vitamin D3 in females with 25-hydroxyvitamin D3 levels < 60 nmol/L.

METHODS

In 131 postmenopausal females screened for participation in an osteoporosis trial, the 25-hydroxyvitamin D3 concentration was < 60 nmol/L. They were treated with 25 (n = 22), 50 (n = 19), 75 (n = 19), 100 (n = 41) or 200 microg (n = 30) of vitamin D3 daily for at least 10 days.

RESULTS

In the females treated with 25, 50, 75, 100 and 200 microg of vitamin D3 daily the 25-hydroxyvitamin D3 concentrations increased significantly from 32.4 +/- 2.7 (mean +/- SEM) to 50.8 +/- 2.9, from 46.7 +/- 2.8 to 65.8 +/- 2.6, from 41.6 +/- 2.7 to 67.4 +/- 2.9, from 46.7 +/- 1.4 to 64.4 +/- 2.2 and from 42.1 +/- 2.0 to 71.2 +/- 2.8 nmol/L, respectively (p < 0.001). S-calcium increased significantly but within the reference range (p < 0.006).

CONCLUSION

Oral vitamin D3 safely increased 25-hydroxyvitamin D3 concentrations in all females above 60 nmol/L. This study demonstrates how to achieve the new recommended 25-hydroxyvitamin D concentrations within the screening period of a clinical trial.