This document summarizes and compares osteomalacia and osteoporosis. It begins with background on bone structure and remodeling and the role of calcium, phosphorus, and hormones like vitamin D and parathyroid hormone in bone metabolism. It then describes osteomalacia as a disease of inadequate bone mineralization typically due to vitamin D deficiency, preventing calcium absorption and weakening bones. Osteoporosis is characterized by gradual bone mass loss and weakness, influenced by aging, nutrition, and other risk factors. While both result in fragile bones that fracture easily, osteomalacia specifically involves low blood calcium and decreased mineralization compared to normal mineralization in osteoporosis.
2. BACKGROUND
Bone is a specialized form of connective tissue which performs a structural function: mechanical support, mobility,
and protection, and is also a mineral reservoir function.
The strength and structure of bone result from the deposition of calcium phosphate salts (hydroxyapatites). Bone is
not a static tissue but it constantly undergoing remodeling by sequential demineralization and mineralization. In
other world, Old bone is constantly being resorbed and new bone formed, the cells responsible for bone formation
are osteoblasts and the cells responsible for bone resorption are osteoclasts.
4. Bone Metabolism Blood calcium and phosphorus homeostasis is essential for normal homeostatic
functions. Control of calcium and phosphors concentration depends on hormonal regulation, as well as
exchange with bone. Three hormones involved in this process: vitamin D, parathyroid hormone (PTH),
calcitonin.
5. OSTEOMALACIA
Osteomalacia is a metabolic bone disease characterized by inadequate mineralization of the bone in adults.
The most common cause of osteomalacia is vitamin D deficiency its produces osteomalacia in two stages. Initially,
decreased vitamin D leads to decreased intestinal calcium absorption and secondary hyperparathyroidism.
Vitamin D deficiency is caused by insufficient sun exposure, decreased intestinal absorption, insufficient intake,
renal or liver failure, and numerous genetic disorders with defects in vitamin D processing, receptors, or binding
proteins.
6. This disorder is uncommon today because of vitamin D–supplemented foods. In adults, factors such as aging,
malabsorption, chronic renal impairment, and use of phenytoin or other anticonvulsant drugs can interfere with
vitamin D absorption, metabolism, or target organ response and result in osteomalacia.
7. OSTEOPOROSIS
Osteoporosis is a disease characterized by a gradual reduction in bone mass that weakens bones and leads to the
occurrence of fractures with minimal trauma.
Osteoporosis can occur as part of the aging process or secondarily due to nutritional deficiency, metabolic
disorders, or medication side effects.
Risk factors for osteoporosis includes nonmodifiable factors such as: female gender, advanced age, white race,
dementia, and modifiable factors such as: poor nutrition especially low calcium and vitamin D intake, alcoholism,
recurrent falls, inadequate physical activity.
9. OSTEOMALACIA OR OSTEOPOROSIS?
OSTEOMALACIA OSTEOPOROSIS
Decreased mineralization Normal mineralization
Low blood calcium Normal blood calcium
Pathological fractures Pathological fractures
10. REFERENCES
• Rinaldo F, Gisela R, Estela S, Manuel J (2015) Biology of bone tissue: Structure, function, and
factors that influence bone cells. Biomed Res Int 1: 17.
• Fitzgerald PA. Osteoporosis. In: Papadakis MA, McPhee SJ, Rabow MW. eds. Current Medical
Diagnosis and Treatment 2020 New York, NY: McGraw-Hill;.
• Osteoporosis and Osteomalacia. In: Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL,
Loscalzo J. eds. Harrison's Manual of Medicine, 20e New York, NY: McGraw-Hill; .
• Nix, S., 2017. Williams' Basic Nutrition And Diet Therapy. 15th ed. St. Louis (Missouri):
Elsevier.
