Bone is a living tissue, comprising mainly calcium and protein. Healthy bone is always being remodeled; that is, small amounts are being absorbed in your body and small amounts are being replaced.
If more bone calcium is absorbed than is replaced, the density or the mass of the bone is reduced. The bone becomes progressively weaker, increasing the risk that it may break.
Osteoporosis means "porous bone." This condition develops when bone is no longer replaced as quickly as it is removed.
More than 2 million fractures occur related to osteoporosis each year. Most people are unaware that they have osteoporosis until a fracture occurs.
The exact medical cause for osteoporosis is not known, but a number of factors are known to cause osteoporosis, including
- Physical inactivity
- Reduced levels of estrogen
- Excessive cortisone or thyroid hormone
- Excessive alcohol intake
The loss of bone tends to occur most in the spine, lower forearm above the wrist, and upper femur or thigh-the site of hip fractures. Spine fractures, wrist fractures, and hip fractures are common injuries in older persons.
A gradual loss of bone mass, generally beginning about age 35, is a fact of life for everyone. After growth is complete, women ultimately lose 30% to 50% of their bone density, and men lose 20% to 30%.
Women lose bone calcium at an accelerated pace once they go through menopause. Menstrual periods cease because a woman's body produces less estrogen hormone, which is important for the maintenance of bone mass or bone strength. Your family doctor or gynecologist may evaluate and recommend a treatment program of estrogen replacement therapy, calcitonin or other medications. To be most effective, the treatment program should begin at menopause.
Although osteoporosis will occur in all persons as they age, the rate of progression and the effects can be modified with proper early diagnosis and treatment.
During growth and young adulthood, adequate calcium nutrition and Vitamin D and regular weightbearing exercises, such as walking, jogging, and dancing, three to four hours a week, build strong bones and are investments in future bone health.
Smoking and consuming excessive amounts of alcohol should be avoided because they increase bone loss. As people age, appropriate intake of calcium and Vitamin D and regular exercise, as well as avoidance of smoking and excessive alcohol use, are necessary to reduce loss of bone mass.
Family doctors working with your orthopaedic surgeon can evaluate whether your bone density has been reduced, and can evaluate the cause for the reduction. Early treatment for osteoporosis is the most effective way to reduce bone loss and prevent fractures. However, treatment programs after a fracture also are of value and may help to prevent future fractures.
Current treatment methods can reduce bone loss, but there are no proven methods of restoring lost bone. Building bones through adequate calcium intake and exercise when you are young is an investment that will pay off years later with a reduced risk of hip and other fractures.
AAOS does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult his or her orthopaedic surgeon, or locate one in your area through the AAOS Find an Orthopaedist program on this website.