What is osteoporosis?

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).

Normal bone is composed of protein collagen and calcium. Osteoporosis depletes both the calcium and the protein from the bone, resulting in either abnormal bone quality or decreased bone density. Bones that are affected by osteoporosis can fracture with only a minor fall or injury that normally would not cause a bone fracture. The fracture can be either in the form of cracking (as in a hip fracture) or collapsing (as in a compression fracture of the vertebrae of the spine). The spine, hips, and wrists are common areas of osteoporosis-related bone fractures, although fractures can also occur in other skeletal areas such as the ribs.

What are the symptoms of osteoporosis?

The osteoporosis process can operate silently for decades. Some osteoporosis fractures may escape detection until years later. Patients may not thus be aware of their osteoporosis until suffering a painful fracture. Then the symptoms are related to the location of the fractures.

Fractures of the spine (vertebra) can cause severe "band-like" pain that radiates around from the back to both sides of the body. Over the years, repeated spine fractures can cause chronic back pain as well as loss of height or curving of the spine, which gives the individual a hunched-back appearance.

A fracture that occurs during the course of normal activity is called a stress fracture. For example, some patients with osteoporosis develop stress fractures of the feet while walking or stepping off a curb.

Hip fractures usually occur as a result of a fall. With osteoporosis, hip fractures can occur as a result of trivial accidents. Hip fractures may also be difficult to heal after surgical repair because of poor bone quality.

What are the consequences of osteoporosis?

Osteoporosis bone fractures are responsible for considerable pain, decreased quality of life, lost workdays, and disability. Up to 30% of patients suffering a hip fracture will require long term nursing home care. Elderly patients can further develop pneumonia and blood clots in the leg veins that can travel to the lungs ( pulmonary embolism) due to prolonged bed rest after a hip fracture. Some 20% of women with a hip fracture will die in the subsequent year as an indirect result of the fracture. In addition, once a person has experienced a spine fracture due to osteoporosis, he or she is at very high risk of suffering another such fracture in the near future (next few years).

Why is osteoporosis an important public health issue?

In the United States, more than 10 million people have osteoporosis of the hip and almost 19 million more have low hip bone density. Between 4 to 6 million postmenopausal white women have osteoporosis, and an additional 13 to 17 million have low hip bone density. One in two white women will experience a bone fracture due to osteoporosis in her lifetime. In 1993, the United States incurred an estimated loss of 10 billion dollars due to loss of productivity and health care costs related to osteoporosis. With the aging of America, the number of people with osteoporosis related fractures will increase exponentially. The pain, suffering, and economic costs will be enormous.

What factors determine bone strength?

Bone mass (bone density) is the amount of bone present in the skeletal structure. The higher the density is, the stronger are the bones. Bone density is primarily determined by genetic factors, which can modified by environmental factors and medications. For example, men have a higher bone density than women. Black Americans have a higher bone density than white or Asian Americans.