Last Updated: 2003-06-03 17:03:24 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Studies have shown that booster seats can reduce injuries in children who are 4 years old and younger, and researchers said Tuesday that the benefit can be extended to children as old as 7.

Children ages 4 through 7 who were belted into a booster seat were half as likely to be injured in a car crash as those who wore only a seat belt, according to a study published in the Journal of the American Medical Association.

And booster seats virtually wiped out injuries to the abdomen and spine, according to the study's lead author, Dr. Dennis R. Durbin of the Children's Hospital of Philadelphia.

"This is the first real-world evidence showing that booster seats do provide an important incremental safety benefit over seat belts alone for children aged four through seven," Durbin said in an interview with Reuters Health.

"What we are hoping is that the results of this study will help both parents and legislators establish a new sense of what 'normal' should be in this group of kids. It should no longer be normal to have only a seat belt."

Durbin and his colleagues scrutinized data from 3,616 crashes that involved vehicles covered by State Farm Insurance Co. The researchers interviewed the parents of the 4,243 children who had been involved in the crashes.

Durbin's team looked only at crashes involving children who were seated in the back seat of the vehicle.

While injuries were reduced across the board by booster-seat use, the results were most dramatic when it came to injuries to the abdomen, spine and lower extremities, Durbin said.

This result doesn't surprise Durbin, who said that these are the types of injuries that result from poor-fitting seat belts.