Vitamin D, calcium and the sex hormones maintain healthy bone. Calcium is the major component of bone that confers strength. Low calcium can lead to osteoporosis. In osteoporosis, there is disruption of the architectural framework of bone that weakens bone. There is increased likelihood for fractures in osteoporosis.
Regulation of Calcium
Calcium is absorbed from the intestines and is regulated by the parathyroid and thyroid glands. These glands produce parathyroid hormone and calcitonin, respectively. Low blood calcium stimulates the parathyroid gland to produce parathyroid hormone that acts on bone, causing it to break down and thereby release calcium into the bloodstream. The thyroid gland produces calcitonin in response to elevated calcium in blood; calcitonin causes the removal of calcium from the blood.
Osteoporosis can occur due to low blood calcium or due to increased breakdown of bone. Diseases that lead to osteoporosis, prevent the use of calcium in maintaining bone.
Risk Factors
The risk for osteoporosis increases with advanced age in both men and women. The female sex is also a risk for osteoporosis. In women, the sex hormone estrogen, becomes deficient in menopause leading to a rapid loss in bone strength; in males a drop in the male sex hormone, testosterone, has less effect on bone.
Excess alcohol and smoking are major risk factors for osteoporosis that can be avoided. Other risk factors include vitamin D deficiency and malnutrition. Being physically inactive can also cause a major loss in bone strength.
Associated Signs and Symptoms
Osteoporosis has no specific symptom but is associated with bone fractures that occur without significant stress on bone. Fractures can occur anywhere throughout the body. When it occurs in the back it can affect posture and reduce mobility. Fracture of a long bone such as the one in the thigh is a serious complication that requires surgery.
The elderly have increased risk of falls and osteoporosis increases the likelihood of fractures associated with falls.
Prevention/Solution
Osteoporosis can be prevented by making lifestyle changes. Quitting smoking and drinking are big steps in preventing osteoporosis. Bone weakens with advancement in age but regular exercise such as walking and jogging, slows down the loss in bone strength. Exercise should be at least 30 minutes a day at least four days per week. Proper dietary intake of vitamin D and calcium can prevent osteoporosis. Diet should include intake of fish, eggs, vitamin D-fortified milk and cod liver oil; these are abundant sources of vitamin D. Vitamin D is synthesized under the skin under direct sunlight. Adequate sunlight exposure helps to prevent osteoporosis.
Screening and Diagnosis
Radiographic imaging such as X-rays, CT scan or MRI confirms a diagnosis of osteoporosis. Imaging studies are only effective for detecting late stages of osteoporosis; it detects mainly fractures. Measuring the bone mineral density, or BMD, by using dual energy X-ray absorptiometry, or DEXA, is effective in diagnosing osteoporosis in both the early and late stages.
The US Preventive Services Task Force, recommends the screening of all women above the age of 65 years and post-menopausal women under 65 years old who are below ideal weight. Screening can lead to earlier treatment and reduction in fracture risk.
Treatment
After the confirmation of osteoporosis, the use of bisphosphonates such as sodium alendronate (Fosamax), risedronate (Actonel) or ibandronate (Boniva), to treat osteoporosis is preferred. These drugs are very effective in reducing the risk of fracture. Oral bisphosphonates, must be taken on an empty stomach. Only physicians can prescribe bisphosphonates; they are not available over the counter.
Estrogen helps maintain normal bone density in women. Post-menopausal women are unable to make estrogen, thereby increasing their risk for osteoporosis; in these women estrogen replacement is effective in preventing osteoporosis.
Vitamin D and calcium must be used in conjunction with other treatment modalities, since they have not proved effective in preventing osteoporotic fractures.
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