For Immediate Release
Contact: Tom Capezzuto
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
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
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
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
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
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.