Calcium is the most abundant mineral in the body. The largest reservoir of calcium is found in bone, giving it strength and form. Calcium also plays roles in chemical reactions such as blood clotting, as well as signaling in nerves and muscle tissues. Osteoporosis is the loss of bone mass, predominantly from the loss of bone minerals such as calcium, making the bones porous and weak. The diagnosis and treatment of calcium disorders, osteoporosis and other conditions should be made with the consultation of a health care professional.
Development and Natural History
The development of osteoporosis involves an imbalance between the development of new bone and the breakdown of old bone. Normally there is an equal balance between the two. In osteoporosis, bone breakdown exceeds bone formation. The calcium in bone is lost, enters the blood stream and is excreted by the kidneys. The complete molecular mechanism leading to this has not been elucidated, but certain risk factors have been defined.
Risk Factors
Some of the risk factors for the development of osteoporosis and the loss of calcium in bone are not changeable. These include female gender, thin build, advancing age, estrogen and testosterone deficiency, Asian and European ancestry and also family history are also risk factors. Some risk factors that can be changed include tobacco and excessive alcohol use. Nutrition problems, such as an inadequate caloric intake can also contribute. Vitamin D is important for regulating calcium levels in the blood and bones, and a deficiency will contribute to osteoporosis. A high protein diet, decreased physical activity, or excessive overactivity may also contribute.
Signs and Symptoms
Osteoporosis generally does not cause any specific symptoms or signs. It carries risks of complications, however. The risk of fracture is greatly increased from the depleted calcium and weakened bone. A fall that would result in little to no damage in a healthy person could cause a fracture in those with osteoporosis. Hip fractures are particularly dangerous in the elderly.
Diagnosis
The diagnosis of osteoporosis involves using radiographic bone imaging to confirm bone loss, and rule out other disorders such as cancer that can contribute to bone fragility. The dual energy X-ray absorptiometry, DEXA, or DXA, is an X-ray technique in which images of two different energies are used to determine the density of bones. A low DEXA score confirms osteoporosis.
Prevention and Treatment
Exercise and an adequate intake of vitamin D and calcium help to prevent osteoporosis. Certain drugs can also help prevent the progression of the disease. Estrogen-like drugs help treat the disease if estrogen deficiency is a contributing factor. Bisphosphonates help regulate the cells in the bone. Some other drugs mimic natural hormones in the body and can also help the condition.
References
- "Robbins and Cotran Pathologic Basis of Disease"; Vinay Kumar et al.; 2009
- "Harrison's Principles of Internal Medicine"; Anthony S Fauci et al.; 2008
Member Comments