Why is vitamin D deficiency not considered the leading risk factor for osteoporosis and treated aggressively before a bisphosphonate is used?
—Luan Q. Pho, MD, Allen, Tex.

Vitamin D deficiency is an important risk factor for osteoporosis and especially osteomalacia. In osteoporosis, calcium and a bisphosphonate are frequently prescribed along with vitamin D because it often will not provide sufficient therapy when used alone. The same is true for glucocorticoid-induced osteoporosis, in which studies show a marginal benefit from vitamin D alone, whereas addition of bisphosphonates provides a more robust response.
—Jack Waxman, MD