Bone density scanning is the best single test for identifying hip fracture risk in older people. But by some estimates, more than half of hip fractures occur among those who do not meet the diagnostic criteria for osteoporosis.
In an effort to address this, University of California at Davis researcher John Robbins, MD, and colleagues developed an 11-question survey designed to predict a postmenopausal (aged 50-79) woman's five-year risk of suffering a hip fracture. They did this by evaluating data from almost 95,000 older women participating in the Women's Health Initiative, an ongoing national health study.
The survey is available in the form of an Internet calculator, which can be found at the web site of the Fred Hutchinson Cancer Research Center.
The factors evaluated in the calculator to predict risk of hip fracture within five years were:
- Race/ethnic group
- General health
- Physical activity
- Personal history of a fracture at age 55 or older
- Parent history of a fracture after age 40
- Current smoking
- Current corticosteroid use
- Treated diabetes
The study is published in the Nov. 28 issue of The Journal of the American Medical Association.
"Bone density scanning is important, but that is just one dimension of hip fracture risk," Robbins tells WebMD. "About half of fractures can be explained by low bone density and about half cannot. That is why we need other ways to evaluate risk."
Race, Weight, and Hip Fractures
These associations have long been known, but Robbins says clinicians often place too much importance in them, ignoring other important factors associated with age-related fracture.
"All things being equal, an African-American woman does have a lower risk than a Caucasian woman, but if all things aren't equal that isn't true," he says. "An African-American woman who has broken her wrist or has a parent who broke a hip may have a risk that is equal to or greater than a Caucasian woman."
Robbins says he hopes the new model will raise awareness among doctors and their elderly female patients about the multiple factors of hip fracture risk.
Because the study included only women, it is not clear if the identified risk factors are equally important in men.
Osteoporosis and High-Trauma Fractures
In a separate study, reported in the same issue of The Journal of the American Medical Association, low bone density was found to be linked to trauma-related, non-spinal fractures in older adults -- such as those resulting from car crashes.
It had been widely assumed that these trauma-associated fractures were not indicative of low bone-mineral density in the elderly, but researchers from the San Francisco Coordinating Center found the opposite to be true.
They write that the findings highlight the importance of evaluating elderly patients who have suffered trauma-related fractures for osteoporosis.
In an editorial accompanying the study, Mayo Clinic researcher Sundeep Khosla, MD, echoes the sentiment. "Fractures previously defined as due to high trauma, such as those from a blunt injury in a motor vehicle crash or a fall from a chair, can no longer be dismissed as being unrelated to osteoporosis," Khosla writes. "Older patients who sustain such fractures should be considered for bone mineral density testing and, if clinically indicated, [receive] further evaluation for osteoporosis."