Healthy bone is maintained by vitamin D, calcium and the sex hormones. Calcium is the major component of bone that confers strength. Low calcium can lead to osteoporosis. In osteoporosis, a disruption of the architectural framework of the bone weakens the bone. Osteoporosis can be prevented or delayed by proper nutrition and lifestyle changes.
How the Body Regulates Calcium
The absorption of calcium in the intestines is facilitated by vitamin D. The concentration of calcium in the blood 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, which acts on bone, causing it to break down and thereby releasing 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 at higher 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 toxic to cells that make bone; they increase risk for osteoporosis and should be avoided. Other risk factors include vitamin D deficiency and malnutrition. Being physically inactive can also cause a major loss in bone strength.
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 will require surgery.
The elderly have increased risk of fall and osteoporosis increases the likelihood of fractures associated with falls.
Prevention
Osteoporosis can be prevented by making changes to lifestyle. 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 of 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 help prevent osteoporosis. Diet should include intake of fish, eggs, vitamin D-fortified milk and cod liver oil as these are abundant sources of vitamin D. Vitamin D is synthesized under the skin in direct sunlight. Adequate sunlight exposure helps to prevent osteoporosis.
Treatment
Osteoporosis is best treated with bisphosphonates such as sodium alendronate, risedronate or ibandronate; these drugs effectively reduce the risk of fracture. Oral bisphosphonates must be taken on an empty stomach. Bisphosphonates are not found over the counter; they are prescribed by a physician.
Estrogen is important in maintaining normal bone density in women. Post-menopausal women are unable to make estrogen, thereby increasing their risk for osteoporosis; a 2006 article in BMJ recommends estrogen replacement in younger post-menopausal women.
Vitamin D and calcium must be used only in conjunction with other treatment modalities, since no studies have been conducted to prove their effectiveness in preventing osteoporotic fractures, states a 2006 study in BMJ.
