Which statements are true regarding vitamin D deficiency?

• A. Increased risk of fracture and other bone deformities
• B. Rickets in children
• C. Insufficient mineralization of newly formed osteoid
• D. All of the above

Answer: (D)

Vitamin D deficiency impairs the body's ability to mineralize bone because it reduces calcium and phosphate absorption from the gut. This leads to weaker bones and a range of skeletal problems. The first statement is true because insufficient mineralization weakens bone structure, increasing fracture risk and causing deformities as bones fail to maintain normal shape under loading. The second statement is true because in growing children, inadequate vitamin D leads to rickets, where bones don’t mineralize properly at the growth plates, producing characteristic deformities and bowed limbs. The third statement is true because osteoid that forms on bone remains inadequately mineralized when vitamin D is deficient, a hallmark of osteomalacia in adults and the defective mineralization seen in rickets. Taken together, these effects explain why vitamin D deficiency can produce fractures, deformities, rickets in children, and insufficient mineralization of new bone—so all of the above.