FOR IMMEDIATE RELEASE
7 February 2008

CONTACT: Fred Hartman
919-653-2584

New Research Suggests Even Low-Level Exposure to Lead May Increase Release of Stress Hormone in Children

Study in Environmental Health Perspectives Adds Weight to the Concern that There Is No Safe Level of Lead Exposure

[Research Triangle Park, NC] A new study suggests children who are exposed to lead, even at low levels, may experience an increase in the release of cortisol - a stress hormone - when they are put under acute stress situations, according to a study in the February 2008 issue of the peer-reviewed journal Environmental Health Perspectives (EHP).

The study included 169 of the 202 children involved in the long-term Oswego Children's Study. Each was tested for levels of the stress hormone cortisol in their saliva while at rest. They were then asked to submerge an arm in ice water for one minute, after which they completed a series of simple tasks with rest breaks in between. The researchers collected their saliva again at 21 minutes, 40 minutes, and 60 minutes after the cold stressor test to measure cortisol levels.

There was no correlation between lead exposure and cortisol levels of children at rest. However, when they were given the acute stress test, children with higher blood lead levels had significantly heightened releases of cortisol.

"The present study demonstrated that prenatal lead exposure was associated with a significant increase in the child's cortisol reactivity to acute stress at 9.5 years of age," the study's authors write. "Comparable but independent effects on cortisol reactivity were observed for postnatal lead exposure. Although the long-term implications for this association are unclear, they are undoubtedly complex. Therefore, it will be important to continue to follow these children, and to determine the consequences of these early effects of lead exposure on glucocorticoid reactivity. Furthermore, future studies should consider cortisol reactivity as a potential mediator for disorders that can be induced by lead, such as fatigue, cognitive impairment, and immune disorders."

The findings were consistent even in children whose blood lead levels were below 10 micrograms per deciliter, which is the action level established by the Centers for Disease Control and Prevention. They were also consistent among children with both prenatal and postnatal lead exposure.

Researchers controlled for many factors, including demographics, socioeconomic status, and the health of the mothers and children, among others.

Prenatal blood lead levels were available for 154 children, while postnatal levels were available for 120 children. All of the children were tested within two weeks of attaining 9.5 years of age.

Authors include Brooks B. Gump, Paul Stewart, Jacki Reihman, Ed Lonky, and Tom Darvill of the Department of Psychology at the State University of New York College at Oswego; Patrick J. Parsons of Trace Elements Laboratory, Wadsworth Center, the New York State Department of Health, and the Department of Environmental Health Sciences, School of Public Health, The University of Albany; and Douglas A. Granger, Behavioral Endocrinology Laboratory, Department of Biobehavioral Health, Pennsylvania State University.

The full article is available online at http://www.ehponline.org/members/2007/10391/10391.html

EHP is published by the National Institute of Environmental Health Sciences (NIEHS), part of the U.S. Department of Health and Human Services. EHP is an Open Access journal. More information is available online at http://www.ehponline.org/. Brogan & Partners Convergence Marketing handles marketing and public relations for EHP, and is responsible for the creation and distribution of this press release.

Editor’s note: Working media can register to receive press releases via e-mail by visiting http://www.ehponline.org/press/, calling 919-653-2584, or e-mailing ehpmedia@brogan.com.