Even Low Lead Levels Appear to Increase Cardiovascular Risk

People with blood lead levels well below those previously considered safe (<10 mcg/dL) have an elevated risk for heart attack and stroke, according to an analysis of NHANES data published online by Circulation.

Nearly 14,000 participants had blood levels measured between 1988 and 1994 and were followed for up to 12 years. After adjusting for a variety of socioeconomic and medical variables, researchers found that compared to participants with lead levels below 1.9 mcg/dL, those with levels between 3.6 mcg/dL and 10 mcg/dL had a hazard ratio of 1.55 for cardiovascular disease mortality, of 1.89 for heart attack mortality, and of 2.51 for stroke mortality. The association of blood lead with cardiovascular mortality was evident at levels as low as 2 mcg/dL, which nearly 40% of U.S. adults exceed.

The authors said the connection between lead and cardiovascular disease is biologically plausible, since increases in blood pressure and renal damage have been observed in animal models of lead exposure. They noted a drawback of the study is its reliance on a single blood-lead measurement to assess exposure.