A new study raises questions about the effectiveness of padded hip protectors worn by older people to help prevent fractures if they fall.

The researchers monitored the health of more than 1,000 nursing home residents with an average age of 85. The residents were asked to wear the pads on just one hip, for comparison purposes.

After 20 months, the study was ended when no difference was found in the fracture rate between the protected and unprotected hip. The study appears in the July 25 issue of The Journal of the American Medical Association. It was led by Dr. Douglas P. Kiel of the Hebrew SeniorLife, a health care organization, and Harvard.

Hip fractures are especially dangerous for older people, and can lead to serious illness and death. The researchers suggested that as new materials were invented, better protection might be possible.

“These results,” the authors write, “add to the increasing body of evidence that hip protectors, as currently designed, are not effective for preventing hip fracture among nursing home residents.”