Osteoporosis is a disease characterized by low bone mass and deterioration of bone structure that increases the risk of fracture. Osteoporosis is often called the “silent disease,” progressing without symptoms until a low-energy fall or minor activity fractures a bone. Osteoporosis can occur without a known cause or be attributed to another secondary condition, such as hyperthyroidism or celiac disease, or to medication, such as steroids.
The epidemiology of osteoporosis has only been fully described in Caucasian women, making estimates of the total number of persons with osteoporosis difficult to determine. In fact, we now know that osteoporosis affects men and women, and all ethnicities. The National Osteoporosis Foundation estimated there were 29.5 million women and 11.7 million men in the U.S. with osteoporosis or low bone mass in 2002. On average in the 1999 to 2004 National Health and Nutrition Examination Survey, nearly 10.5 million men and women aged 65 and older reported they had been told by their doctor they had osteoporosis, a rate of 26 in 100 women and 4 in 100 men (Table 1). These rates of osteoporosis are dramatically higher than those found a decade earlier, likely due to increased testing of bone mass and extensive educational and awareness efforts. It is believed that osteoporosis is significantly underdiagnosed. In 2004, only 16 percent of persons admitted to the hospital with a low-energy fracture were diagnosed with osteoporosis.
Falls are the leading cause of injury among persons aged 65 and older in the United States. Fractures are the primary cause of hospitalization or death following a fall. Osteoporosis is a leading underlying cause of low-energy fractures after a fall. One in two women and one in four men older than age 50 will have an osteoporosis-related fracture in her or his remaining lifetime.