In adults, what condition can result from a deficiency of vitamin D?

A deficiency of vitamin D in adults primarily leads to osteomalacia. This condition is characterized by the softening of the bones due to inadequate mineralization, particularly a deficiency of calcium and phosphate that are essential for bone health. Vitamin D plays a crucial role in calcium homeostasis and bone metabolism; when its levels are insufficient, the body's ability to absorb calcium from the diet is impaired, negatively impacting bone density and strength.

While osteoporosis, which is often confused with osteomalacia, involves the loss of bone density and structure, it is more associated with factors such as aging, hormonal changes, and a sedentary lifestyle rather than a direct deficiency in vitamin D. On the other hand, scurvy results from a deficiency in vitamin C, and pellagra arises from inadequate niacin (vitamin B3), neither of which are related to vitamin D levels. Thus, osteomalacia distinctly represents the condition linked to vitamin D deficiency in adults.