North Dakota health officials are recommending that pregnant women and young children avoid eating meat from wild game killed with lead shot.

The recommendation is based on a study released Wednesday that examined the lead levels in the blood of more than 700 state residents. Those who ate wild game killed with lead shot appeared to have higher lead levels than those who ate little or no wild game.

The elevated lead levels were not considered dangerous, but North Dakota says pregnant women and children younger than six should avoid eating venison harvested using lead shot.

Those groups are considered most at risk from lead poisoning, which can cause learning problems and convulsions, and in severe cases can lead to brain damage and death.

The study, conducted by the U.S. Centers for Disease Control and Prevention and the state health department, is the first to connect lead traces in game with higher lead levels in the blood of game eaters, said Dr. Stephen Pickard, a CDC epidemiologist who works with the state health department.

A separate study by Minnesota's Department of Natural Resources previously found that fragments from lead shot spread as far as 46 centimetres away from the wound.

"Nobody was in trouble from the lead levels," Pickard said. "The effect was small but large enough to be a concern."

Pickard said the study found "the more recent the consumption of wild game harvested with lead bullets, the higher the level of lead in the blood."

Officials in North Dakota and other states have warned about eating venison killed with lead ammunition since the spring, when a physician conducting tests using a CT scanner found lead in samples of donated deer meat.

The findings led North Dakota's health department to order food pantries to throw out donated venison. Some groups that organize venison donations have called such actions premature and unsupported by science.

The Canadian government began phasing out the use of lead shot in 1999 to cut down on the amount of the pollutant, which can poison birds.