Childhood exposure to lead is associated with adult criminal behaviour, including violent crime, finds a new study in this week’s PLoS Medicine. Dr Kim Dietrich and colleagues (University of Cincinnati, USA) studied the association between exposure to lead in the uterus and during early childhood and criminal arrests in adulthood, in poor areas of Cincinnati.
Lead is known to be toxic to the nervous system. Childhood exposure has been identified as a potential risk factor for antisocial behaviour 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 overcomes both of these limitations.
Between 1979 and 1984, the researchers recruited pregnant women living in poor areas of Cincinnati, which had a high concentration of older lead-contaminated housing. Out of the 376 newborns recruited into the study, 250 were included in the final analysis. Blood lead levels were measured during pregnancy and then regularly until the children were six and a half years old, as an indication of their lead exposure. This exposure was then correlated with local criminal justice records on how many times each of the 250 offspring had been arrested between becoming 18 years old and the end of October 2005.
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% (the “relative risk” was 1.48).
The authors discuss a number of limitations in their study including not being able to capture 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 and colleagues, “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.
In an expert commentary on this study, Dr David Bellinger (Harvard Medical School, Boston, USA)—who was uninvolved in the research—says “even if the contribution of lead to arrest risk is small, however, it has a special status in that, in contrast to most other known risk factors for criminality, we know full well how to prevent it.” Dr Bellinger notes that while lead’s detrimental effect on IQ is the outcome most often studied, impaired IQ “is clearly only the tip of the iceberg” when it comes to the harms of childhood lead exposure.
CITATION: Wright JP, Dietrich KN, Ris MD, Hornung RW, Wessel SD, et al. (2008) Association of prenatal and childhood blood lead concentrations with criminal arrests in early adulthood. PLoS Med 5(5): e101.
IN YOUR COVERAGE PLEASE LINK TO THIS URL, WHICH WILL PROVIDE ACCESS TO THE PUBLISHED PAPER: http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0050101
PRESS-ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/plme-05-05-dietrich.pdf
Related image for press use (please feel free to reproduce this image as long as you credit the image source):
- http://www.plos.org/press/plme-05-05-dietrich.jpg (Image Credit: Cincinnati Historical Society)
- Caption: Children at play in a 1950s era tenement in Cincinnati, Ohio
CONTACTS:
Amanda Harper
Public Relations and Communications
University of Cincinnati Academic Health Center
Cincinnati, Ohio
United States of America
+1 513 558-4657 (direct)
+1 513 604-3308 (cell)
+1 513 558-2910 (fax)
amanda.harper@uc.edu
Kim Dietrich
University of Cincinnati College of Medicine
Environmental Health
3223 Eden Avenue
Cincinnati, Ohio 45267-0056
United States of America
+1 513-558-0531
+1 513-558-4838 (fax)
kim.dietrich@uc.edu
Related PLoS Medicine Perspective:
Citation: Bellinger DC (2008) Neurological and behavioral consequences of childhood lead exposure. PLoS Med 5(5): e115.
IN YOUR COVERAGE PLEASE LINK TO THIS URL, WHICH WILL PROVIDE ACCESS TO THE PUBLISHED PAPER: http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0050115
PRESS-ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/plme-05-05-bellinger.pdf
CONTACTS:
David Bellinger
Harvard Medical School
Department of Environmental Health
Boston, MA
United States of America
+1 617-355-6565
+1 617 730-0618 (fax)
David.Bellinger@childrens.harvard.edu
Journal
PLoS Medicine