State laws that mandate car booster seat use for children at least until age 8 are associated with fewer motor vehicle-related fatalities and severe injuries, and should be standardized throughout the U.S. to optimally protect children, according to new research presented Oct. 22 at the American Academy of Pediatrics (AAP) National Conference and Exhibition in New Orleans.

The AAP recommends that be secured in a belt-positioning until the child reaches 4 feet, 9 inches in height, sometime between the ages of 8 and 12. While many states have booster seat laws that mirror these requirements, some states have varying standards for how long a child should remain in the booster seat. For example, some states only require booster seat use until the age of 6 or 7.

In "Booster Seat Laws Reduce Motor Vehicle Fatalities and Injury," researchers reviewed data from the between January 1999 and December 2009, comparing fatality and incapacitating injury rates in states before and after booster seat .

There were 9,848 fatalities and incapacitating injuries in children ages 4 to 8 over the 10-year period. The study found a decreased rate (20 percent) of death/incapacitating injuries for children 4-6 years old in states with booster seat laws compared to states without booster seat laws, and an even higher reduction (33 percent) in the 7- to 8-years-old age bracket. Children ages 4 to 6 with no or improper restraint were twice as likely to suffer death or an incapacitating injury, and 7- to 8-year-olds were four times as likely compared to those child properly restrained in a booster seat.

In addition, children ages 4 to 6 with only a lap/ (no booster seat) had a 20 percent increased odds of death or an incapacitating injury, compared to children properly restrained in a booster seat. The odds ratio was even more pronounced among 7- to 8-year-olds: a 70 percent increased risk of death or incapacitating injury for children wearing only a lap/shoulder belt.

"Many states have booster seat laws. However, there are different requirements for how long the child should remain in the booster seat," said Lois K. Lee, MD, FAAP, the senior author of the abstract. "Our analysis supports the fact that booster seat laws should follow AAP standards to optimally protect children when they are riding in a motor vehicle."