Blood lead levels generally considered "safe" actually may be associated with an increased risk of death from many causes, including cardiovascular disease and stroke, according to a report in Circulation: Journal of the American Heart Association.

In the report, researchers Investigated lead levels below 10 micrograms per deciliter (µg/dL)--previously considered safe.

"Our study found the association of blood lead with cardiovascular death to be evident at levels as low as 2 µg/dL," said Paul Muntner, Ph.D., author of the study and an associate professor of epidemiology and medicine at Tulane University in New Orleans. "Since 38 percent of U.S. adults had lead levels above 2 µg/dL in 1999-2002, the public-health implications of these findings are substantial."

Since the mid-1970s, when lead was banned for use In gasoline, household paint, and soldered food cans, average blood lead levels in American adults have decreased from 13.1 µg/dL to 1.6 µg/dL.

Today, lead is mostly used to make batteries, pipes, and roofing materials. Breathing contaminated air, eating contaminated food or soil, or drinking contaminated water are ways people can be exposed to lead. Inhalation of airborne lead is generally the most significant source of occupational lead absorption.

"Our study had limited ability to evaluate the risks of lead exposure associated with blood lead levels below 2 µg/ dL," Munther said. "Future research is needed to identify the level of lead exposure that is not associated with major health outcomes. Although markedly reduced, the current blood lead levels may not be low enough, and we believe that practical and cost-effective methods for reducing lead exposure in the general U.S. population are needed."