Aggregate-level lead exposure, gun violence, homicide, and rape.

CONTEXT: An increasing body of research has linked the geographic distribution of lead with various indicators of criminal and antisocial behavior. OBJECTIVE: The current study, using data from an ongoing project related to lead exposure in St. Louis City, MO, analyzed the association between aggregate blood lead levels and specific indicators violent crime within the city. DESIGN: Ecological study. SETTING: St. Louis, Missouri. EXPOSURE MEASURE: Blood lead levels. MAIN OUTCOME MEASURE: Official reports of violent crimes were categorized as 1) crimes involving a firearm (yes/no), 2) assault crimes (with or without a firearm), 3) robbery crimes (with or without a firearm), 4) homicides and 5) rape. RESULTS: With the exception of rape, aggregate blood-lead levels were statistically significant predictors of violent crime at the census tract level. The risk ratios for each of the outcome measures were as follows: firearm crimes 1.03 (1.03-1.04), assault crimes 1.03 (1.02-1.03), robbery crimes 1.03 (1.02-1.04), homicide 1.03 (1.01, 1.04), and rape 1.01 (0.99-1.03). CONCLUSIONS: Extending prior research in St. Louis, results suggest that aggregated lead exposure at the census tract level predicted crime outcomes, even after accounting for important sociological variables. Moving forward, a more developed understanding of aggregate level crime may necessitate a shift toward studying the synergy between sociological and biological risk factors such as lead exposure.

Prenatal smoking and genetic risk: examining the childhood origins of externalizing behavioral problems.

An ever-growing body of research has begun to focus closely on the role of prenatal smoke exposure in the development of conduct problems in children. To this point, there appears to be a correlation between prenatal nicotine exposure and behavioral problems. We build on this prior research by examining the coalescence of prenatal smoke exposure and genetic risk factors in the prediction of behavior problems. Specifically, the current study analyzed data from a nationally representative sample of twin pairs collected during early childhood. Our findings suggested that an interaction existed between prenatal smoke exposure and genetic risk factors which corresponded to increased risk of behavior problems. These findings provide evidence of a gene-environment interaction, in that prenatal smoke exposure conditioned the influence of genetic risk factors in the prediction of aggressive behavior. Interestingly, the association between genetic risk and prenatal smoking was sex-specific, and only reached statistical significance in females. Given the nature of our findings, it may shed light on why heterogeneity exists concerning the relationship between prenatal smoke exposure and externalizing behavioral problems in children.

Unraveling the covariation of low self-control and victimization: a behavior genetic approach.

A growing body of literature examining the antecedents of victimization experiences has suggested that personality constructs play a role in the origins of victimization. Low self-control, in particular, represents a trait thought to directly increase the risk of victimization. At the same time, different lines of evidence suggest that genetic factors account for portions of the variance in both self-control and victimization. These findings leave open the possibility that the two traits might covary because of previously unmeasured genetic factors. The current analysis seeks to test this possibility. Additionally, we examine whether the covariation between self-control and victimization persists once genetic effects are held constant. Our findings suggest a nuanced explanation for the relationship between self-control and experiences of victimization.