Your bones give your body its shape, help you move, and support your body. Your bones also help protect your heart, lungs, and brain. Even though your bones feel hard and rigid, bones are living tissues that are constantly rebuilding themselves during your life.
During your childhood and teenage years, your body adds new bone faster than it gets rid of old bone. After about age 30, you can start to lose bone faster than your body makes bone, which makes your bones weaker and more likely to break. Some bone loss is natural as both men and women age. Still, it's important to take steps to make sure you don't lose too much bone and put yourself at risk of easily breaking a bone by falling or tripping.
You may hear your doctor talk about "bone density" or "bone mineral density." Both terms describe a measurement of how strong your bones are. The higher the density, the stronger and healthier your bones are.
Women are at higher risk of bone loss than men. When a woman goes through menopause, whether as a natural part of the aging process or because of breast cancer treatment, her levels of estrogen and other hormones drop sharply. Estrogen helps maintain bone density, and a drop in estrogen can lead to significant bone loss.
You may hear your doctors use two different words to talk about low bone density:
- Osteopenia means you have lower-than-normal bone density. Osteopenia isn't a disease, but it can mean that you're at higher risk for breaking a bone.
- Osteoporosis is a disease and means that your bone density is so low that your bones are brittle and can break easily. White and Asian women are at highest risk for osteoporosis, but all women and men older than 50 are at risk for the disease.
Women who have been diagnosed with breast cancer face an even higher risk of osteoporosis because some breast cancer treatments can cause bone loss.
There are a number of tools that your doctor can use to check your bone health, including a physical exam and blood and urine tests to measure your calcium levels.
Bone density tests use x-rays or sound waves to measure how strong your bones are. Bone density tests are used to definitively diagnose bone loss and osteoporosis.
The most widely recognized bone mineral density test is dual-energy x-ray absorptiometry, commonly known as a DEXA scan. A DEXA scan uses low levels of x-rays and is quick and painless. A scanner passes over your whole body while you're lying on a cushioned table. A DEXA scan can measure the bone mineral density of your whole skeleton, as well as specific points that are more likely to break, such as the hip, spine and wrist. Using a DEXA scan to measure bone mineral density at the hip and spine is considered the most reliable way to diagnose osteoporosis and predict the risk of breaking a bone.
For more detailed information on bone loss, osteoporosis, and ways to keep your bones strong, visit the Bone Health section.