What’s Your Bone Density?

Health, Home & Family
on January 6, 2008

You probably know that osteoporosis is a disease that weakens bones and can lead to debilitating fractures, but did you know a quick and painless test exists to determine the strength of your bones?

A bone mineral density test measures the amount of calcium and other minerals in your bones. The test can help your doctor diagnose and begin treating osteoporosis before you begin breaking bones.

“It’s a major predictor of the strength of the bones and the ability of bones to withstand minor forces,” says Dr. Felicia Cosman, a professor of clinical medicine at Columbia University in New York City. “It is the way we define osteoporosis. If your bone density is reduced by a significant level it’s actually considered osteoporosis.”

Testing your bones
Several methods can be used to measure bone density, but the most common and preferred test is called a dual energy X-ray absorptiometry, or DXA, test. Typically, it measures bone density at the hip and lower spine, where fractures often occur.

The DXA test is done while lying, fully clothed, on a padded table while a scanner passes over your body. The painless, noninvasive test uses very low levels of radiation—less than that of a single chest X-ray, Cosman says.

The test result compares your bone density to the average bone density of a healthy young adult. If you have normal bone mass, your score will be above minus 1. A score between minus 1 and minus 2.5 means that you are losing bone mass, and a score below minus 2.5 indicates osteoporosis.

Mary Jo Coffee, 63, underwent her second bone density test last summer after falling and breaking a kneecap. The test took less than 10 minutes. “It’s very easy,” says Coffee, a retired community college career counselor in Menomonee Falls, Wis. (pop. 32,647). “It’s not anything like a colonoscopy. When you think of that kind of test, this is so simple.”

Coffee’s first test, five years ago, determined that she had low bone density, but not low enough to warrant an osteoporosis diagnosis. Results of her second test showed that she still has low bone density, so she is increasing the calcium in her diet by eating yogurt every day, drinking milk three times a day and taking supplements. She also has started walking and lifting weights several times per week to help strengthen her bones.

Should you be tested?
A bone density test is recommended for women who are 65 and older, and for men who are 70 and older; osteoporosis is especially prevalent in these age groups, as bones naturally become weaker with age. In fact, one in two women and one in four men over age 50 will break a bone because of osteoporosis.

A doctor also may recommend the test for younger women and men who have other risk factors for the disease, such as a family history of osteoporosis, certain medical conditions, a fracture or low body weight.

If a bone density test shows that you have osteoporosis or are at high risk for developing it, your doctor may prescribe medication and suggest lifestyle changes such as exercising and eating calcium-rich foods. A person with solid bone density may not need another test for five years. If you have been diagnosed with osteoporosis or low bone density you may need to be tested more often, perhaps once a year.

Protecting your bones
A healthy diet rich in calcium and vitamin D helps to keep bones strong. Bones store calcium for basic functions of the body, and when we don’t get enough in our diet our bodies take calcium from our bones, weakening them.

Most adults require 1,200 milligrams of calcium daily. Good sources of calcium include dairy products such as milk, yogurt and cheese, as well as canned salmon and leafy greens. Vitamin D is important because it helps our bodies absorb calcium. Depending on age, adults need 400 to 1,000 international units of Vitamin D3, the best type of vitamin D for our bones, each day. Fortified milk and soy drinks are good sources of vitamin D, which also is found in fish, liver and egg yolks, and is produced by our bodies when skin is exposed to sunlight.

Exercise, especially weight-bearing exercise, also is recommended, and so is a healthy lifestyle, which means no smoking or excessive drinking.

Women over 50 are particularly at risk for osteoporosis, so Cosman recommends that all women get a bone density test when they reach menopause. A DXA test costs about $150. In some cases, Medicare or health insurance plans will cover part of the cost.

“The cost of this particular procedure is so cheap,” Cosman says. “It’s a zero-risk test, and it can provide so much information that I think every woman at menopause or thereafter should think about getting the test.”