High lead levels linked to high blood pressure

NEW YORK (Reuters Health) - High levels of lead in the blood and in bone seem to raise the likelihood of developing high blood pressure, but this may be related in part to low levels of calcium in the diet, according to two studies.

In the first study in the medical journal Epidemiology, Dr. Barbara S. Glenn, from the US Environmental Protection Agency in Washington, DC, and colleagues show that blood pressure responds relatively quickly to changes in lead levels.

The study involved 575 people in South Korea who had worked for an average of 8.5 years in a job that exposed them to lead. The researchers measured lead levels and blood pressure in the subjects, whose average age was 41, from October 1997 to June 2001.

The authors found that as lead levels changed on a yearly basis, so did blood pressure. This suggests that it is not just the cumulative lead dose over a lifetime that influences blood pressure.

In the second study, Dr. Howard Hu, from the Harvard School of Public Health in Boston, and colleagues looked at how dietary calcium affects the link between lead levels and blood pressure. The analysis involved 471 men from the Normative Aging Study who had lead levels and dietary calcium assessed with standard measures.

Bone and blood lead levels were associated with hypertension only among subjects with low calcium intake, defined as less than 800 milligrams daily.

"Dietary calcium may be helpful in prevention of hypertension induced by elevated lead burden," the researchers conclude.

SOURCE: Epidemiology, September 2006.