introduction
Osteoporosis is a skeletal disorder characterized by increased fragility of bones with increased tendency to fracture. In this condition, there is a decrease in bone density and strength due to a disruption of the normal balance between new bone production and old bone removal or resorption.
Osteoporosis can occur at any age, but is more prevalent with increasing age. The National Institutes of Health estimates an approximate 10 million people living with osteoporosis in the United States.
How Osteoporosis Develops
Normal bone health is based on a balance between new bone formation and old brittle bone removal. New bone formation is carried on by special bone cells called osteoblasts. Old, brittle bone removal is carried out by osteoclasts. These two cell groups work to maintain the bones in the best state of fresh density.
Certain factors adversely affect this balance, favoring bone resorption and inhibiting new bone formation. Advancing age with the waning of positive hormonal influences of estrogen, especially in menopausal women, leads to increased risk of osteoporosis. This is the most important risk factor. Other risk factors include certain lack of physical exercise, poor nutrition, genetic makeup, medications like steroids, alcohol and tobacco use.
Treatment of Osteoporosis
The surgeon general's report in 2004 on the state of the nation's bone health recommends a pyramidal approach to the prevention and treatment of osteoporosis.
Foremost is a broad based approach to good bone health with adequate physical exercise and nutrition to provide the perfect environment for healthy bone development or repair. Some physiotherapy might be needed in those who have difficulties with movement or are recovering from paralysis or fractures. Mineral and vitamin supplements are also useful.
The second aspect of treatment is the assessment and elimination of secondary causes of osteoporosis that might interfere with therapy if left untreated. The secondary causes of note include hormonal imbalances like high levels of cortisol or parathyroid hormones which weaken the structure of bone. Medications that lead to or worsen osteoporosis may have to be withdrawn to allow a good response to other treatment. Social habits like alcohol and tobacco use are addressed at this point.
The third aspect is drug therapy, which involves basically two approaches. The first approach in drug therapy is to stop the resorption or thinning of bone. This allows new bone formation to assume the upper hand in the balance, leading to increased bone density and decreased likelihood of fractures. The primary drugs used here are the bisphosphonates like Alendronate (fosamax) and risendronate (actonel). These are prescription drugs taken under close monitoring by the prescribing physician. They suppress osteoclast resorption of bone. Another aspect of drug treatment is hormone replacement therapy in the menopausal. Estrogen replacement therapy has a proven track record in reversing bone loss in post menopausal women. The problem of possible development of cancer in the postmenopausal women on estrogen alone has prompted its combination with progesterone-like agents to reduce the propensity for cancer development in these women. Other agents used here are Raloxifene, an estrogen-like drug and Calcitonin, a hormone secreted by the thyroid gland to counter bone resorption. Diverse combinations of drugs from this group can be used to counter bone resorption.
The second approach in drug treatment is to stimulate new bone formation. This is achieved by the use of agents that stimulate osteoblasts like periodic low dose injections of parathyroid hormone or the use of an artificial form of the hormone called teriparatide.
New directions of treatment
Combinations of antiresorptive therapy and bone stimulation have also been applied to good effect. Other treatment modalities are still being evaluated. Osteoporosis induced by different types of cancer is the focus of recent research.
