Blog | Thursday, February 9, 2012

Set the right frequency for bone mineral density tests

The recommendations for when and how often women should be tested for osteoporosis with bone density testing (DXA Scan) has been vague. Many women are tested in their early 50s when they go through menopause with follow up tests as frequently as every year. Others break a hip without ever being tested.

A new study published in the New England Journal of Medicine states that bone loss develops slowly and women who have a normal test when they are 65 do not need to be retested for 15 years. Even women who show some bone loss can wait many years before they are tested again, according to the study authors.The study followed 5,000 women over age 67 for over 10 years. These women did not have osteoporosis at the beginning and they found fewer than 1% of women with normal beginning bone density developed osteoporosis over the next 15 years. Only 5% of women who started with mild bone loss developed osteoporosis.

This study points to the fact that we have been over testing normal women who would not develop significant bone loss. But there are a few aspects of the study that are important to note. They only studied women with normal or slightly low bone mineral density (BMD). Women who have had prior broken bones, or who have significant bone loss at the time of screening should be followed more closely, perhaps every 3-5 years.

Not everyone agrees with the 15 year recommendation either. "An interval of 15 years is too long", says Felicia Cosman, MD, senior clinical director for the National Osteoporosis Foundation. She cites flaws in the study design. Here is what I recommend for patients. Get a screening BMD test at age 60-65. If you are a smoker, take corticosteroid drugs, are thin and fair, or have a mother or sister with osteoporosis or a broken hip, have the first screening test within 5 years of your last menopause period. If that first DXA test is in the normal range, there is no reason to repeat the test for at least 10 more years. If the first test shows mild to moderate bone loss, repeat in 3 years to assess stability. The most important test is the first one to establish a baseline and further testing should be tailored toward each individual woman.

There is an easy online tool that can help women and men calculate their risk of having a fracture in the next 10 years. It can help guide us to when we need to get a bone mineral density test by taking account of certain known risk factors.

This post originally appeared at Everything Health. Toni Brayer, FACP, is an ACP Internist editorial board member who blogs at EverythingHealth, designed to address the rapid changes in science, medicine, health and healing in the 21st Century.