Researcher links lead to violence

After studying the effects of childhood lead exposure for nearly 30 years, a University of Cincinnati researcher has found a positive correlation to violent criminal behavior and a deterioration of brain cells.

"We started the study in 1979 and recruited women who were pregnant or living in areas of Cincinnati that have high incidents of lead poisoning such as Over- the-Rhine, the West End, Avondale and some parts of Price Hill," said Kim Dietrich, the principal researcher and professor and director of epidemiology and biostatistics. "We followed these children and looked at their lead exposure from the time they were in the womb into post-natal development until they were 6-to 7-years-of-age."

Most of the individuals in the study are now in their mid-20s and continue to maintain contact with Dietrich and his team.

"I've been involved with these kids for three decades and they ask me 'Why can't I hold onto a job? Why can't I maintain a stable domestic relationship?'" Dietrich said. "The argument is over; it's important for society as a whole to clearly put lead on the table as the culprit for problem children in the inner city who have low academic achievement."

Dietrich's study looked at the early exposure to lead and the number of officially documented arrests in Hamilton County. In comparing the levels of lead exposure to the number of arrests, Dietrich found a "substantial correlation between lead and crimes involving violent acts." In this study, violent acts include, but are not limited to, domestic violence, assault, robbery and weapons possession.

Unexpectedly, the correlation between early exposure to lead and violent crimes was not the only conclusion drawn the study.

The members of the study also had MRIs taken of their brains. With these images, researchers found a loss of brain cells in the part of the brain that affects the central nervous system. The brain cells lost are associated with the part of the brain that controls impulsive behavior, aggression, judgment and emotional regulation, Dietrich said.

"It was a fluke," Dietrich said of the brain damage correlation to lead exposure. "We found a definitive link between damage to the brain and social judgment and a relationship to the number of arrests for total violent criminal offenses that has never been done before. This is the longest study in the world of its kind."

The primary source of lead exposure in Cincinnati is found in old paint chips that contain lead.

"Over-the-Rhine, the West End, Avondale and Price Hill historically have high incidences of childhood lead poisoning," Dietrich said. "There were high expectations the children would be exposed to lead before they were even born and that's exactly what we found. The source of exposure comes from lead paint residue from dust in homes and lead in the soil from years and years of sloughing off of exteriors dating back to pre-World War II."

Dietrich and his team are continuing to look at the environmental effects on children of lead, mercury and other chemical factors that can impact the development of the central nervous system.

"No matter what we look at in terms of environmental exposure, lead always comes up as a major factor that diminishes the central nervous system even at the lowest levels of exposure," Dietrich said. "We're going to pursue further research on gene interactions in respect with lead."