Exposure to lead in the uterus and during early childhood is associated with adult criminal behavior, including violent crime, finds a new study in PLoS Medicine.
Lead is known to be toxic to the nervous system and childhood exposure has been identified as a potential risk factor for antisocial behavior in adulthood. But this link has relied on indirect measurement of childhood lead exposure in adults or has measured childhood lead exposure directly but has not followed lead-exposed children into adulthood. The new study, by Dr Kim Dietrich, from the University of Cincinnati, overcomes both of these limitations.
The researchers found that increased blood lead levels before birth and during early childhood were associated with higher rates of arrest for any reason and for violent crimes. For example, for every 5ug/dl increase in blood lead levels at six years of age, the risk of being arrested for a violent crime as a young adult increased by almost 50 percent.
The authors note the limitations of not being able to measure all criminal behavior (since most criminal behavior does not lead to arrest) and being unable to assess IQ (lead exposure impairs intelligence, which in turn makes it more likely that a criminal offender will be arrested). Despite these limitations, the study's findings, say Dr Dietrich, "implicate early exposure to lead as a risk factor for behaviors leading to criminal arrest."
Although both environmental lead levels and crime rates have dropped over the last 30 years in the US, the overall reduction was not uniform — inner-city children remain particularly vulnerable to lead exposure. The findings therefore suggest that a further reduction in childhood lead exposure might be an important and achievable way to reduce violent crime.
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Source: Public Library of Science
