Childhood lead exposure has been linked to smaller brains and criminal behavior in adulthood, reports the Los Angeles Times. Researchers studying childhood blood contamination in old Cincinnati buildings with lead-based paint discovered that each 5 microgram-per-deciliter increase in blood lead levels by the age of 6 was accompanied by a 50% increase in violent crime. The affect was strongest among males.
A related study discovered that the children with the highest lead levels had the smallest brains, with decision-making and impulse control areas among the most affected. The studies show the clearest connection yet between lead and crime. Researchers warned that lead exposure is still harming many children today, despite government efforts to clean up contamination.