Lead Exposure Linked to Violent Crime, Brain Changes

May 28, 2008 -- Exposure to lead during childhood increases the likelihood of being arrested for violent crime -- and is linked to decreased volume in regions of the brain associated with judgment and problem solving, according to two new studies.

Numerous earlier studies have found relationships between lead exposures and behavioral problems in children, including aggression, antisocial behavior, attention deficit hyperactivity disorder and juvenile delinquency.

Last year Jessica Wolpaw Reyes of Amherst College in Amherst, Mass., published a report showing that the U.S. phase-out of leaded gasoline in the late 1970s could explain much of the decline in crime seen from 1992 to 2002, as children exposed to less lead became adults.

By accounting for confounding variables and considering results state-by-state where the phase-out happened at different times, Wolpaw Reyes calculated that for every 10 percent decline in grams of lead per gallon gasoline, violent crime rates decreased by 7.9 percent.

The new studies, published in PLoS Medicine, help confirm the link between lead exposure and crime by connecting direct measurements of childhood lead exposures to adult behavior, and by showing a biological change in the brain that is consistent with the observations.

The studies follow 250 people born between 1979 and 1984, who Kim Dietrich of the University of Cincinnati College of Medicine began tracking before they were born.

He recruited them from the Cincinnati inner city where dilapidated, older housing often containing chipping lead-based paint and lead-containing dust tends to increase lead exposure.

Dietrich combined the measurements he made of the children's lead levels both prenatally and at various stages in their childhood with public arrest records.