Osteomalacia is bone softening caused by excessive resorption of calcium from the extracellular bone matrix and/or lack of vitamin D.

• A. Osteomalacia
• B. Osteoporosis
• C. Osteoarthritis
• D. Rickets

Answer: (A)

Osteomalacia is a mineralization problem: bones are laid down but fail to mineralize properly because of vitamin D deficiency, leading to soft, weak bones in adults. Vitamin D is essential for calcium and phosphate absorption; when it’s deficient, these minerals are less available for bone mineralization, and osteoid remains poorly mineralized. The result is bone pain, tenderness, and a higher risk of fractures despite normal or even increased bone formation. This distinguishes it from osteoporosis, where the issue is reduced bone mass and bone quality without a primary defect in mineralization, and from rickets, which is the pediatric version of the same mineralization defect that also affects growing bone and growth plates. While secondary changes like increased bone turnover can occur, the defining feature is defective mineralization caused by vitamin D deficiency, yielding softened bones.