Osteoporosis occurs when a person loses bone density or makes too little bone. This makes the bones weak and susceptible to breakage from a usually innocuous fall – or, in more severe cases, simple, everyday actions such as bumping into something.
The word osteoporosis means “porous bone.” According to the National Osteoporosis Foundation (www.nof.org), about 10 million Americans have osteoporosis. Half of all women older than age 50 will break a bone because of osteoporosis.
Osteoporosis is often called a “silent” disease because many people do not know they have it or are at risk for getting it. Risk factors for osteoporosis include being over age 50, female and menopausal, and family history. Patients with a low body weight, who are small and thin and do not get enough calcium and vitamin D are also at risk. Inactivity, smoking and overconsumption of alcohol can make someone more susceptible to osteoporosis. Some medical conditions, such as diabetes, cancer, multiple sclerosis, hyperthyroidism or celiac disease, might also cause bone loss.
Osteoporosis is diagnosed through a bone-density test. This test uses a dual-energy X-ray absorptiometry machine (DXA) to estimate a patient’s bone density. Low bone density is known as osteopenia. The WHO Fracture Risk Assessment Tool uses information about the patient’s bone density and other risk factors for breaking a bone to estimate her or his 10-year fracture risk. Blood and urine tests can give an indication of the patient’s blood calcium levels, urine calcium measurement and thyroid function for further evaluation. A 25-hydroxyvitamin D test can determine whether the body has enough vitamin D, which is vital for bone health.
Osteoporosis medication is divided into two categories: antiresoprtive medications, which slow bone loss, and anabolic drugs, which increase the rate of bone formation. Bone is living, growing tissue that continuously renews and changes through a process called remodeling. There are two distinct stages in bone remodeling: resorption and formation. Resoprtion is when osteoclasts dissolve bone tissue and create small cavities. Osteoblasts fill the cavities with new bone tissue during formation. An imbalance in this procedure can cause bone loss.
Antiresorptive medications such as bisphosphonates, calcitonin and denosumab slow bone loss. Anabolic drugs increase the rate of bone formation. Teriparatide is currently the only osteoporosis medicine approved by the Federal Drug Administration that rebuilds bone. Other drugs commonly prescribed for osteoporosis include alendronate sodium (Fosamax®), which reduces bone loss and increases bone density; ibandronate sodium (Boniva®), which is approved for the prevention and treatment of osteoporosis in postmenopausal women; and risedronate, which slows bone loss, increases bone density and reduces the risk of spine and non-spine fractures by 35 percent to 45 percent over three years. Calcitonin is a synthetic hormone for the treatment of osteoporosis in women who are at least five years beyond menopause.
Patients with osteoporosis should be encouraged to get enough calcium and vitamin D in their diet and to exercise. They should also be made aware that they will not feel their bones getting stronger, but the physician can share ongoing results of their bone-density tests with the patients to reassure them their medication and other measures are indeed working. An especially telling indication of the benefits of treatment is if the patient does not break any bones.
By Tanya J. Tyler, Associate Editor