July 27 (UPI) -- A second bone-density test doesn't improve physicians' ability to determine the risk for osteoporosis-related hip, spine, forearm and shoulder fractures in postmenopausal women, a study published Monday by JAMA Internal Medicine found.
The first test was more predictive of fracture risk than a second test, suggesting the latter may be unnecessary, the researchers said.
"Repeated bone mineral density testing three years after a baseline bone density test should not be routinely performed in post-menopausal women not taking osteoporosis medication," study co-author Dr. Carolyn Crandall told UPI.
"Resources should go toward improving the under-use of bone density testing among women aged 65 to 85 years, one-quarter of whom do not receive an initial bone density test," said Crandall, an internal medicine specialist at UCLA Health.
A bone density test is the only test that can diagnose osteoporosis before a bone fracture occurs, according to the National Osteoporosis Foundation.
The foundation recommends bone density tests for all women age 65 and older, as well as women of menopausal age and post-menopausal woman under 65 with risk factors for osteoporosis, including a family history of the condition.
People treated with prescription drugs for osteoporosis should undergo bone density testing every one to two years, according to the foundation. Those at lower risk for the condition, however, can wait five years or more to repeat the procedure, based on current guidelines.
Physicians routinely perform bone density tests in post-menopausal patients approximately three years after the first to gauge any loss in bone mass and assess patients' bone fracture risk in subsequent years, according to Crandall and her colleagues.
For this study, the researchers used data collected from more than 7,000 post-menopausal women 50 to 79 years old from across the United States who were followed for nine years as part of the Women's Health Initiative.
Study participants underwent bone mineral density measurements at the start of the study and again about three years later, the researchers said. After the second test, participants reported whether they experienced major osteoporosis-related fractures.
Just under 10% of the study participants had an osteoporosis-related fracture over the course of the study, according to the researchers.
And any change in bone density between the first and subsequent tests was no more effective at identifying women at risk for fractures than the findings on the first test alone, they said.
"Our study focused on the most common scenario, where women who are postmenopausal receive a repeat bone density test three years after an initial bone density test," Crandall said.
"Women who are at particularly high risk for fracture due to medication or diseases that are harmful to bone -- for example, chemotherapy or prednisone -- are in a special situation that was not the focus of our study and merit closer follow-up of their bone health," she said.