Keeping guns unloaded and locked up can go a long way toward protecting children against accidental injury or suicide, Seattle researchers say.

In a study of nearly 600 households, the scientists found about a 70 percent reduction in the risk of such injuries or suicide if guns were locked or kept unloaded.

Locking up ammunition and storing it separately from the gun also lowered the risk by 61 percent and 55 percent, respectively.

"Gun owners need to take only one of these actions. Just taking any one ... is associated with a reduction in the risk," said Dr. David Grossman, who led the study when he was director of the Harborview Injury Prevention and Research Center.

Previous research has determined that about 35 percent of homes in the United States with children younger than 18 have at least one firearm, and 43 percent of those homes have at least one unlocked gun. Other studies reported in various medical journals have concluded that having a firearm in a home is associated with an increased risk of a teen committing suicide.

Grossman, now director of preventive care at Group Health Cooperative, and his colleagues interviewed people from 106 households where someone under 20 intentionally or accidentally shot themselves or accidentally shot someone else. The homes were in 37 counties in Washington, Oregon and Missouri.

The researchers also interviewed people in 480 households where no shootings occurred. Then they compared gun-storage practices in the two groups. Financed by the Centers for Disease Control and Prevention, the study results are published in today's edition of the Journal of the American Medical Association.

Grossman, a pediatrician, said most people associate gun safety at home with protecting small children. But he said it also is needed to help protect teens against suicide, the third leading cause of death in adolescents.

The safety measures are especially needed when a teenager in the home suffers from depression or is engaged in substance abuse, Grossman said.

Warren King: 206-464-2247 or wking@seattletimes.com