Up through puberty and somewhat beyond, children continue to grow and build bone. Peak bone mass is achieved by early adulthood and generally remains stable until about the third decade of life. After that, bone loss occurs at a more rapid rate than bone formation. Most adults lose about one percent of their peak bone mass/year.
Osteoporosis is a condition of low bone mass, in which the bones become fragile and are susceptible to fracture. In many cases, an unexpected fracture is the first sign of the disease. The most common sites of fracture are the hip, spine, and wrist. Other symptoms can include low back pain, neck pain, loss of height over time, and stooped posture.
According to the National Osteoporosis Foundation, it affects about 10 million people in the U.S. Nearly 34 million Americans have low bone mass and are at risk for developing osteoporosis. The condition is four times more common in women, who lose up to 20 percent of their bone mass within five to seven years after menopause.
Osteoporosis can have serious consequences. The condition causes about 1.5 million fractures yearly. About half of women and 25 percent of men will experience at least one osteoporosis-related fracture during their lifetimes. In 2001, the annual cost of treatment for osteoporosis fractures was $17 billion.
Low Bone Mass in Teens
Since peak bone mass begins to decline after about age 30, it's important to build strong bones early in life. That means getting an adequate intake of calcium and vitamin D during childhood and through the teen years. Children with abnormally low bone mineral density (a condition called osteopenia) may be at greater risk for osteoporosis later in life when bone mass begins to decline. In severe cases, patients may even experience bone fractures during childhood.
Sometimes the cause of childhood osteopenia can't be found. In many cases, however, the condition can be traced to a specific problem. Inadequate nutrition (especially low intake of calcium and vitamin D) may limit the body's ability to form new bone. Cola beverages contain phosphoric acid and caffeine, which may interfere with bone mineralization and increase the risk of bone fractures. (In addition, many children drink soda in place of milk, an important source of calcium and vitamin D.)
Medical conditions, such as juvenile arthritis, diabetes, Crohn's disease, cystic fibrosis, osteogenesis imperfecta, kidney disease, anorexia, and hyperthyroidism, can affect bone formation and bone mineral density. Medications, such as anti-convulsants, corticosteroids, and immunosuppressive agents, may also increase the risk of osteopenia.
Children who are at risk for osteopenia because of medical conditions, treatments, lifestyle factors, or unexplained fractures, may need to be evaluated for bone mineral density. The current standard for testing is dual-energy X-ray absorptiometry (DEXA scan), which uses X-rays to measure the mineral content of bones. If bone mineral density is found to be low, doctors will try to find the source of the problem.
Sometimes better treatment of underlying medical conditions may improve bone mineralization. Nutritional deficiencies can often be treated with diet and exercise. Children who are anorexic may need extensive counseling to overcome their poor eating patterns. Some children may need calcium supplementation. Several medications have been approved to treat low bone mass in adults, but these medications haven't been fully tested in children.
For general information on osteoporosis:
National Institutes of Health Osteoporosis and Related Bone Diseases~National Resource Center, www.osteo.org