Vitamin D therapy.

The fat-soluble vitamin D prohormones, ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3), are essential for the efficient intestinal absorption of calcium and phosphate and the subsequent mineralization of bone. Inadequate vitamin D leads to chronic secondary hyperparathyroidism and osteoporosis. The increasing prevalence of osteoporosis has paralleled a pandemic of vitamin D insufficiency. Based on observational and prospective trials with clinical end points, the standards for vitamin D sufficiency have been recently revised. All patients with osteopenia or osteoporosis should be monitored with a reliable assay to maintain serum 25-hydroxyvitamin D levels more than 32 ng/dL. Patients who are taking bisphosphonates and those with coexisting primary hyperparathyroidism are not exempt from taking supplemental vitamin D.