"People who ate a lot of wild game tended to have higher lead levels than those who ate little or none," Dr. Stephen Pickard, epidemiologist for the North Dakota Department of Health, said Wednesday.

The study also showed that the more recent the consumption of wild game killed with lead bullets, the higher the level of lead in the blood.

The blood lead levels of those tested were considered low, but even low levels can have adverse health effects, especially for children and pregnant women.

Officials recommended that pregnant women and children under 6 not eat any venison from deer killed with lead bullets -- the same recommendation made last month by the Minnesota Health Department.

"Children under 6 are particularly vulnerable because their brains are still developing," Pickard said. "It causes permanent brain damage even in very small quantities. There is no safe exposure level for small children. We see children with permanent lower intelligence and changes in behavior."

Lead can increase the risk that a pregnant woman could lose her baby or deliver it prematurely, Pickard said. In adults, lead can cause high blood pressure, hearing loss and infertility, though usually with higher lead levels.

The study, done by the U.S. Centers for Disease Control and Prevention (CDC) and the North Dakota Department of Health, appears to add to the evidence that using lead bullets can pose potential health problems for hunters and their families. A Minnesota study last summer showed lead bullets fired from high-powered rifles scatter lead fragments -- many too small to see or feel -- up to 18 inches from the wound.