Press Release

For Immediate Release
Contact: Tom Capezzuto
(973) 972-7273

At UMDNJ-New Jersey Medical School
Researchers Find That Lead Exposure Promotes Aggressive Behavior Study Published in July Issue of Environmental Research

Lead poisoning and environmental exposure to lead may cause aggressive and even violent behavior, according to a study conducted by researchers at the University of Medicine and Dentistry of New Jersey (UMDNJ).

The findings of the laboratory study by researchers at the UMDNJ-New Jersey Medical School in Newark will be published in the July issue of Environmental Research. Dr. John D. Bogden, professor of preventive medicine and community health; Dr. Allan Siegel, professor of neurology and neurosciences, and Dr. Donald B. Louria, chairman emeritus of the Department of Preventive Medicine and Community Health at the medical school, are lead investigators of the study.

Dr. Bogden said, "The data of this study demonstrate that lead exposure enhances predatory aggression in animals, and provide support for lead exposure as a cause of aggressive behavior in humans."

Dr. Louria said, "The results support other recent investigations that have found associations between lead in blood or bones and delinquent and aggressive behavior in teenagers. In humans, there are many variables that make it more difficult to sort out the effects of lead on behavior. In experiments with animals, we can demonstrate the specific effects of lead administered in very precise doses."

In the controlled study, which was funded by the National Institutes of Health, the researchers placed small amounts of lead in the food of five laboratory animals to measure the effects of lead exposure on their behavior. They then conducted trials in which predatory attack behavior of the animals was measured by applying small electrical impulses to a region of the brain that controls behavior.

Currents were measured three times per week for a total of six to 10 weeks, including before, during and after lead exposure. The predatory attack threshold current, the lowest current that provoked aggressive behavior, decreased significantly during lead exposure in three of five animals and increased after discontinuing lead exposure in four of them.

The researchers also found that lower predatory attack thresholds were correlated with higher blood lead concentrations for each animal. A decrease in the threshold current that induces predatory attack means that the animal is behaving more aggressively.

Dr. Bogden said the animals involved in the study survived the experiment and suffered no permanent damage.

Lead poisoning is the most prevalent pediatric disease of environmental origin in the United States, and thousands of children have high blood lead levels. Pediatric lead poisoning results principally from the ingestion of very small quantities of lead from environmental sources, primarily paint chips, dust and soil, but also from drinking water and many other sources.

National screening data show that blood lead concentrations have decreased substantially since the 1970s, but low level lead exposure remains a significant public health problem, especially in children living in large cities.

"The primary concern is effects of lead on the brain that include delayed development, diminished intelligence, lower school achievement and altered and more aggressive behavior," Dr. Louria noted. "In children, these effects have been reported to occur at low blood lead concentrations in the same range as those of the cats in the study."

Other investigators involved in this study include Dr. Wenjie Li, a postdoctoral research fellow; Dr. Shenggao Han and Dr. Amy Davidow, assistant professors; Francis Kemp, research specialist, all from the Department of Preventive and Community Medicine; and Thomas Gregg, a graduate student in the Department of Neurology and Neurosciences.

The UMDNJ-New Jersey Medical School is one of three medical schools of the University of Medicine and Dentistry of New Jersey. UMDNJ comprises New Jersey's only three medical schools, the state's only dental school, a nursing school, a graduate school of biomedical sciences, a school of health related professions and a school of public health on campuses in Newark, Piscataway/New Brunswick, Camden, Stratford and Scotch Plains. UMDNJ also operates University Hospital, Newark, and University Behavioral HealthCare. It is affiliated with more than 200 health care and educational institutions throughout the state.

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