Growing evidence shows that exposure to lead in the environment is associated with cardiovascular disease, including increased risk of hypertension. However, those studies have looked at lead concentrations in blood, not bone lead, a better indicator of cumulative lead exposure over time. In a new study, researchers at the Harvard School of Public Health (HSPH) and the University of Michigan School of Public Health found that bone lead was associated with a higher risk of death from all causes, particularly from cardiovascular disease. It is the first study to analyze the association between bone lead and mortality.
The study appears online on September 8, 2009, on the website of the journal Circulation and will appear in a later print edition.
"The findings with bone lead are dramatic. It is the first time we have had a biomarker of cumulative exposure to lead and the strong findings suggest that, even in an era when current exposures are low, past exposures to lead represent an important predictor of cardiovascular death, with important public health implications worldwide," said Marc Weisskopf, assistant professor of environmental and occupational epidemiology at HSPH and lead author of the study.
Air pollution was the main source of lead in the environment in recent years, though it has been decreasing since leaded gasoline was banned in the U.S. in the mid-1990s. Most of the lead circulating in the body is deposited in bone and remains there for years, unlike blood lead, which has a half life of about 30 days. Since adverse effects from lead on the cardiovascular system would be expected to show up over time, the researchers expected that bone lead would be a better marker of chronic toxicity.