Survivors of gunshot wounds that leave bullet fragments lodged in the body may face a little-recognized long-term risk-elevated lead levels.

Researchers found that among 365 gunshot victims with retained bullet fragments, 12 percent had blood lead levels at or above the threshold for “medical concern” three months after being shot.

This percentage declined over time, fluctuating between two and five percent over the next year and a half. Still, researchers say even these lower figures suggest that of the 1 to 2 million gunshot survivors in the U.S., tens of thousands could unknowingly have lead levels high enough to threaten their health.

Study co-author Dr. Stephen J. Rothenberg recommended that gunshot victims with retained bullets have their blood lead levels monitored over time.

Rothenberg is with the National Institute of Public Health in Cuernavaca, Mexico, and Charles R. Drew University of Medicine and Science in Los Angeles. He and his colleagues report their findings in the current issue of the American Journal of Epidemiology.

Lead is well known to have toxic effects when it reaches a persistently high concentration in the body. Young children and developing fetuses are especially vulnerable, as even relatively low lead exposure can damage the developing brain and cause learning and behavioral problems. But adults with persistently high lead levels may face health consequences as well-including high blood pressure, and damage to the kidneys, brain and nerves.

In the US, chips and dust from the lead-based paints still found in some older homes are a major source of lead exposure. Drinking water is another potential source, particularly when a home has old, lead-based pipes. Because of this, research and public health efforts have focused on cutting people’s ingestion of lead.

Little attention has been paid to what happens when a bullet embeds lead into body tissue.

Rothenberg said his study was prompted when co-author Dr. Joseph L. McQuirter, a surgeon who has removed bullet fragments from many gunshot victims, asked a “very sensible question”: Is there a risk of lead poisoning when bullets or fragments remain lodged in the body?

To investigate, the researchers followed gunshot victims treated at King-Drew Medical Center in Los Angeles, which sees more than a thousand such patients each year.

They found that three months after hospital admission, nearly 12 percent of patients had blood lead levels of at least 20 micrograms per deciliter of blood-levels that are “cause for medical concern,” Rothenberg said. In addition, 38 percent had lead levels elevated to at least 10 mcg/dL.

These percentages declined slowly over time, the researchers found, but two years after being shot, two percent of patients still had lead levels at or above 20 mcg/dL. Overall, the greater the number of lodged bullet fragments, the greater the odds that patients would sustain high lead levels.

If patients’ bullet fragments cannot be safely removed, there is no way to reduce chronically elevated blood lead levels, the study authors point out.

Rothenberg said the problem has to be tackled on a case-by-case basis, with doctors weighing the risk of surgery against the health risk of persistently high lead levels.

Most of the study patients had been shot with handguns, which are likely to leave lead-containing bullet fragments in the body. Injuries from a rifle, which may be sustained in military conflict or hunting accidents, present less of a lead-exposure risk due to the types of bullets used and the typical nature of wounds, according to Rothenberg.

Still, he said he recommends repeated testing of blood lead levels for all patients with lodged bullet fragments, regardless of the type of gun that did the damage.

SOURCE: American Journal of Epidemiology, April 2004.