A new, first-of-its-kind study demonstrates a direct correlation between elevated blood-lead levels and arrests for violent crime. The study looked at blood-lead levels for 250 people from before birth through their seventh year. That data was collected between 1979 and 1991, and recently researchers looked at the criminal arrest records for the same subjects.
The results were clear as day. Higher blood lead levels at any point in childhood were an accurate predictor of arrests for violent crime later in life.
Wait a second. Haven't we seen that before?
The conclusion's basically the same, but the methodology sets this study apart. Previous studies have been criticized for for their indirect measures -- like the one that pointed to a correlation between the ban on leaded gasoline and a worldwide drop in crime rates, or studies that have found elevated blood-lead levels in people who've been arrested. Those studies have presented strong data, but some naysayers have argued that they don't hold water.
Those naysayers will have a harder time denying the connection between lead exposure and violent criminal activity now. The new study produced specific numbers:
The researchers found, for example, that every 5-microgram-per-deciliter increase in blood lead levels at age 6 was accompanied by a 50% increase in the incidence of violent crime later in life.On top of that, another set of researchers looked at the brain-weight of a sample of subjects from the original study. They found an inverse correlation between blood-lead levels and brain weight -- that is, people with more lead in their systems during childhood also had the smallest brains. The areas of the brain that were most impacted? Those regulating "decision making, impulse control, attention, error detection, task completion and reward-based decision making." Seriously. Could the evidence be any more compelling?