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Dorothy N.'s avatar

If I may, I would like to point to the fact that previously, violent crime in the US fell naturally some time after 'they got the lead out' of gasoline. The world has been since been inundated in many other neurotoxins, but higher levels of lead exposures were strongly linked with violence and aggression.

In at least one such past discussion, it was pointed out that then-current US 'leaders' were from that high lead-exposure era. (Something which might help explain the now elderly/sometimes now-deceased Neo-Cons/Neo-Libs obsessed with war propaganda/coups/military attacks/coups/assassinations in other societies for resource theft and geo-political land thefts by imposing their own selected US-interest-serving dictators upon other people's countries.

(I don't recall exactly how that was phrased, only that such as that was at least strongly implied and may or may not have been specified.)

I'm very tired, and this, following, is simply the first study up on the first page under the terms in which I searched, but this IS an important point; we have ALL long been globally increasingly subjected to neurotoxins, including novel applications/life/brain damaging frequencies, and this seems rarely discussed, despite potential relevance to violent crime rates and societal deterioration especially in the most-affected areas and groups of humanity.

There are, of course, many potential injurious factors, but anything that damages the higher levels of cognition is a MAJOR problem and I have long thought that the assault in this area is not merely incidental.

There was a time when many good studies were freely available and easily found, but it seems that THAT time has passed - something I again believe to be not merely incidental.

(Illustrated quoted chunks below)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5703470/

PLoS One. 2017; 12(11): e0187953.

Published online 2017 Nov 27. doi: 10.1371/journal.pone.0187953

PMCID: PMC5703470

PMID: 29176826

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

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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.

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Introduction

Lead absorption, both in utero and early across childhood, has been linked to a variety of deleterious outcomes related to overall physiological and neurological growth (for a general review, see) [1]. Regarding neurological outcomes in particular, lead absorption early in development has been prospectively associated with reductions in total brain volume and to reductions in gray matter [2]. These differences, by extension, are thought to impair impulse regulation and to reduce general intelligence for exposed individuals across the remainder of the life course [3–10]. Most recently, Rueben and colleagues [9] sought to further test the association between early life lead exposure and IQ by examining over 500 participants from New Zealand (the Dunedin cohort) tracked across over 30 years of development. After adjusting for a range of confounders (e.g., mother’s intelligence), increased lead exposure was associated with lower overall intelligence in adulthood, as well as lower scores on measures of perceptual reasoning and working memory (but not verbal comprehension and processing speed measures).

The link between lead exposure and neural development becomes particularly important for understanding the development of violent tendencies, as several lines of evidence have found that diminished functioning in the prefrontal cortex is associated with impulsivity as well as with antisocial and violent behavior [11]. Indeed, neurological insults, such as the ones possibly predicted by lead exposure, have been hypothesized to play a key role in the development of serious and persistent criminal conduct [1,8,10]. This relationship was also anticipated by Moffitt’s [12] theoretical work, which suggested early neurological insults meaningfully increase the risk of acting violently across the life course. Seemingly supportive of such a hypothesized link, several studies have reported an association between lead exposure and the risk for a variety of delinquent and antisocial behaviors [13] including criminal conduct at the individual level [4, 8–10, 14]

Lead exposure & crime in the aggregate

Equally important, however, is the consideration that environmental sources of lead exposure are not uniformly distributed across the population [15]. Rather, lead exposure risk is often concentrated geographically [16–17]. If it is the case that exposure to lead influences behavior at the individual level, then it is plausible that areas with increased levels of ambient lead might jointly experience increased aggregate levels of criminal behavior. One method of testing this possibility is via the use of ambient air-lead levels, and indeed these measures have been linked statistically with a number of aggregate criminal outcomes such as homicide and assault rates [17–18]. Areas with increased levels of lead in the air—across various units of analysis—experienced higher rates of criminal behavior measured in a variety of different ways [17–18]. Yet, it remains premature at this point to reach any strong conclusions about macro-level measures of lead exposure and crime rates due in part to several lingering methodological concerns [16].

Macro-level researchers have long known that spatial autocorrelation, for instance—the tendency for certain outcomes to cluster together geographically for reasons other than a causal association between those two variables—can bias parameter estimates [19]. This potential bias is important because it could lead to incorrect conclusions about the relationship between lead exposure and crime rates. Boutwell et al. [16] drew on macro-level data from St. Louis and uncovered a significant association between blood lead levels and violent, non-violent, and total crime rates across census tracts even after adjusting for potential confounders and spatial autocorrelation. Though suggestive, the effect of aggregate lead levels on broad crime rates obscures the specific types of criminal involvement that lead might impact. Prior macro research examined particularly violent forms of crime (e.g., homicide) [17], yet it remains less clear whether lead exposure raises the risk of only certain types of crime across a wider variety of crime types that it might plausibly impact. In an effort to answer these questions, and to extend existing bodies of evidence, we examined data related to lead exposure measured at the census tract level, and a variety of violent forms of criminal behavior.

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Methods

Study design

Using data drawn from an ongoing project on urban lead exposure we assessed the association between aggregate blood lead levels and violent crime rates across all 106 Census tracts in St. Louis City Missouri, USA [16, 20]. Concentrated disadvantage, age of the housing stock, and residential mobility were considered important covariates and were included in all statistical models.

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