Nov. 28 (HealthDay News) -- High-trauma fractures, such as those caused by vehicle crashes or from steep falls, are associated with weak bones, researchers report.

Older adults who experience such fractures outside of the spine are at risk of another fracture and should be assessed for osteoporosis, the U.S. study concludes.

This challenges current assumptions, said the authors, who noted that it's widely believed -- without any supporting evidence -- that these types of fractures "are not related to low bone mineral density (BMD) or subsequent fracture risk and therefore are presumed not to be manifestations of osteoporosis."

The result: Many doctors treating older adults with high-trauma fractures don't order an osteoporosis evaluation. Doctors may also erroneously believe that high-trauma fractures can't be prevented by osteoporosis treatments that boost bones' density and strength, noted Dawn C. Mackey, of the San Francisco Coordinating Center and colleagues.

Her team analyzed data from two previous U.S. studies of more than 8,000 women and almost 6,000 men aged 65 and older.

They found that low bone mineral density was associated with increased risk of high- and low-trauma fracture. Each 1-standard deviation (SD) decrease in total hip bone mineral density was associated with a 45 percent increased risk of high-trauma fracture in women and a 54 percent increased risk in men. Each 1-SD decrease in total hip bone density was associated with a 49 percent increased risk of low-trauma fracture in women and a 69 percent increased risk in men, the team found.

Furthermore, women who sustained a high-trauma fracture had a 34 percent increased risk of a subsequent fracture compared to women who didn't suffer a high-trauma fracture. Women who experienced a low-trauma fracture were 31 percent more likely to suffer a subsequent fracture than women who didn't sustain a low-trauma fracture.

The study is published in the Nov. 28 issue of the Journal of the American Medical Association.

SOURCE: Journal of the American Medical Association, news release, Nov. 27, 2007