Which statement best describes osteomalacia?

• A. It is due to lack of vitamin D and defective mineralization of osteoid
• B. It is due to excessive bone resorption
• C. It presents with increased bone density
• D. It occurs only in children

Answer: (A)

Osteomalacia is defined by defective mineralization of osteoid in mature bone caused by vitamin D deficiency. Without enough vitamin D, calcium and phosphate absorption from the gut drops, so newly formed osteoid isn’t properly mineralized. The result is soft, weak bones that can cause bone pain, proximal muscle weakness, and a higher risk of fractures. Radiographs may show stress-like pseudofractures (Looser zones). Lab findings often include elevated alkaline phosphatase with low vitamin D, and possibly low calcium or phosphate with secondary hyperparathyroidism. This differs from conditions of excessive bone resorption or increased bone density, and it is not limited to children (rickets occurs in children, while osteomalacia occurs in adults).