Bone-loss in glucocorticoid-induced osteopenia is most evident in trabecular bone such as the vertebrae. Bone mineral content (BMC) measurements of the spine were prospectively studied, comparing the preventive effect of calcium (500 mg a day) and calcium plus Vitamin D (4000 IU on alternate days) during long-term corticosteroid treatment. A small increase in BMC was noted in both groups, but no differences between preventive calcium and calcium plus Vitamin D became evident. It is suggested that patients who are receiving prednisone should be advised to use supplemental calcium.