American Board of Family Medicine (ABFM) Practice Exam

Which vitamin deficiency is associated with osteomalacia?

1. Vitamin A

2. Vitamin B12

3. Vitamin C

4. Vitamin D

The correct answer is: Vitamin D

Osteomalacia is a condition characterized by the softening of the bones, often due to a deficiency in vitamin D. This vitamin is crucial for maintaining proper bone health because it aids in the absorption of calcium and phosphorus, which are vital minerals for bone formation and strength. When there is insufficient vitamin D, the body struggles to absorb these minerals effectively, leading to a decrease in bone mineralization and resulting in osteomalacia. Vitamin D deficiency can occur for various reasons, including inadequate sunlight exposure, poor dietary intake, malabsorption syndromes, or certain medical conditions that affect the metabolism of vitamin D. The insufficiency of vitamin D directly impacts bone structure, as it causes the bones to lose their mineral content, becoming soft and more prone to deformities and fractures. While the other vitamins listed—A, B12, and C—play important roles in various bodily functions, their deficiencies are not primarily associated with the development of osteomalacia. Vitamin A is important for vision and immune function, vitamin B12 is essential for red blood cell formation and neurological function, and vitamin C is crucial for collagen synthesis and overall skin health. However, none of these vitamins directly affect bone mineralization in the way that vitamin D does.