What is osteoporosis?
Osteoporosis is a disease of bone in which the amount of bone is decreased and the strength of trabecular bone is reduced, cortical bone becomes thin and bones are susceptible to fracture. Osteoporosis is condition that features loss of the normal density of bone. Osteoporosis leads to literally abnormally porous bone that is more compressible like a sponge
than dense like a brick. This disorder of the skeleton weakens the bone leading to an increase in the risk of breaking bones (bone fracture).
'Osteo' means bone, and 'porosis' thinning or becoming more porous, so osteoporosis literally means 'thinning of bone.' It is commonly confused with the word osteoarthritis, which is a form of arthritis that results in breakdown of the cartilage covering the ends of bones. In contrast, osteoporosis is a condition where bone itself breaks down. Bones then become thin, brittle and easily broken. For example, sneezing can cause a person's rib to break or stumbling can lead to fracture of one of the bones in the spine. Osteoporosis can cause a great deal of suffering, including loss of independence or even death, especially when the fracture involves the hip. Hip fractures can be difficult to heal, and reduce the person's ability to move around, which can lead to complications and other health problems. Up to 36 percent of older people who fracture a hip die within a year of the injury.
Like other organs in the body, bone tissue is constantly being broken down and reformed again. This turnover is necessary for growth, for repair of minor damage that occurs from everyday stress, and for the maintenance of a properly functioning body. Two essential cells are involved in this process: Osteoclast cells are formed from certain blood cells and are responsible for the breakdown, or resorption, of the skeleton. These cells dig holes into the bone and release the small amounts of calcium into the bloodstream that are necessary for other vital functions. Osteoblast cells are produced by bone cells and are the bone builders. They rebuild the skeleton, first by filling in the holes with collagen, and then by laying down crystals of calcium and phosphorus.
In normal bone, bone formation and bone resorption are closely coupled. In osteoporosis, the net rate of bone resorption exceeds the rate of bone formation, resulting in a decrease in bone mass without a defect in bone mineralization. In women, osteoclast activity is increased because of decreased estrogen; as men and women age > 60 yr, osteoblast activity drops off. Men with prematurely decreased testosterone may have increased osteoclast activity. These changes result in further net loss of bone. The amount of bone available for mechanical support of the skeleton eventually falls below the fracture threshold, and the patient may sustain a fracture with little or no trauma. Bone loss affects both cortical and trabecular bone. Histologically, there is a reduction in cortical thickness and in the number and size of trabeculae of cancellous bone, with normal width of the osteoid seams. Trabecular bone loss predominates in typical postmenopausal osteoporosis. A defect in mineralization (osteomalacia) and osteoporosis can coexist.
Peak bone mass is achieved by both men and women in their 20s and 30s. After that time there begins a period of the net bone loss. With the onset of menopause, women begin an accelerated period of bone loss that may increase by tenfold so that they may lose bone at the rate of 3-6% per year (Christiansen 1994). Osteoclasts, the bone cells that break down bone, are activated by a loss of estrogen and a subsequent elevation of inflammatory factors that stimulate bone resorption (removal of bone from the body with transport to the blood).
In osteoporotic bones, calcium leaches from the bone mass and as a result small holes form in the bones. Presence of these holes causes bone weakening. As the process continues, trabecular struts are lost and the pores and empty spaces within the bone grow larger. Initially, only minute breaks may occur in the weakened bone tissue. Eventually, though, major fractures result. As the disease progresses, other characteristics show up: compression of the vertebrae resulting in loss of height and the hunched back deformity known as dowager's hump.
Osteoporosis occurs most often in older people and in women after menopause. It affects nearly half of all those, men and women, over the age of 75. Women, however, are five times more likely than men to develop the disease. They have smaller, thinner bones than men to begin with, and they lose bone mass more rapidly after menopause (usually around age 50), when they stop producing a bone-protecting hormone called estrogen. In the five to seven years following menopause, women can lose about 20% of their bone mass. By age 65 or 70, though, men and women lose bone mass at the same rate. As an increasing number of men reach an older age, there's more awareness that osteoporosis is an important health issue for them as well.
More information on osteoporosis
What is osteoporosis? - Osteoporosis is a thinning and weakening of the bones, usually associated with the aging process. Osteoporosis is a disease, often with no detectable symptoms.
Building and maintaining skeletal health - Factors involved in building and maintaining skeletal health are adequate nutrition and body weight, exposure to sex hormones at puberty, and physical activity.
What types of osteoporosis are there? - Osteoporosis can be classified in various ways based on diagnostic categories, etiology. Osteoporosis can be classified as either primary osteoporosis or secondary osteoporosis.
What causes osteoporosis? - Osteoporosis is related to the loss of bone mass that occurs as part of the natural process of aging. Osteoporosis results when there is excess bone loss without adequate replacement.
What are the risk factors for osteoporosis? - Many disorders are associated with increased risk of osteoporosis. Osteoporosis is far more prevalent in women after menopause due to the loss of the hormone estrogen.
What're the risk factors for primary osteoporosis? - Risk factors for primary osteoporosis include age, gender, race, figure type, lifestyle, diet, and lack of sunlight.
What're the risk factors for secondary osteoporosis? - Risk factors for secondary osteoporosis include genetic disorders, hypogonadal states, endocrine disorders,hematologic disorders, nutritional deficiencies, drugs.
What are the consequences of osteoporosis? - Consequences due to osteoporosis are increased risk of fracture with minor trauma, frequency of traumatic events from lifting and bending impact.
What are the symptoms of osteoporosis? - Patients with uncomplicated osteoporosis may be asymptomatic or may have pain in the bones or muscles, particularly of the back. Osteoporosis becomes apparent in dramatic fashion.
How is osteoporosis diagnosed? - The diagnosis of osteoporosis is usually made by your doctor using a combination of a complete medical history and physical examination.
What're the treatments for osteoporosis? - Treatment for osteoporosis includes eating a diet rich in calcium and vitamin D, getting regular exercise, and taking medication to reduce bone loss and increase bone thickness.
What osteoporosis medications (drugs) are available? - Medications (drugs) to cure osteoporosis include bisphosphanates (Fosamax), calcitonin (Miacalcin), raloxifene, estrogen, and selective estrogen receptor modulators (SERMs).
How to treat osteoporosis in men? - Alendronate and teriparatide have been approved to treat osteoporosis in men. Calcitonin may work in men, treatment with testosterone appears to increase bone density.
How to treat osteoporosis in women? - The non-hormonal bisphosphonate drugs, alendronate and risedronate prevent and treat postmenopausal osteoporosis. Raloxifene is approved for preventing and treating osteoporosis.
What lifestyle changes can help osteoporosis? - Alcohol consumption should also be kept within safe limits. Supplements of calcium plus vitamin D may help maintain bone density. Limiting sodium and avoiding junk food.
What osteoporosis exercises are suggested? - Exercise is very important for slowing the progression of osteoporosis. Taking regular exercise is the single most important action improve the strength of their bones.
What osteoporosis diet is suggested? - A good calcium intake is essential throughout life for healthy bones. Vitamin D helps the absorption of calcium from the intestines. Reducing salt may be useful for osteoporosis patients.
What can be done to prevent osteoporosis? - For prevention and treatment of osteoporosis, patients should be encouraged to stop smoking, limit alcohol consumption and perform weight-bearing exercise.
Osteoporosis and calcium - Calcium could alter the physical-chemical properties of the bone mineral. The daily recommended dietary calcium intake varies by age, sex, and menopausal status.
Osteoporosis and magnesium - Magnesium supplementation is as important as calcium supplementation in the treatment and prevention of osteoporosis.
Osteoporosis and vitamin D - Vitamin D is necessary for the absorption of calcium in the stomach and gastrointestinal tract and is the essential companion to calcium in maintaining strong bones to prevent osteoporosis.