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December 26, 2017

"Association of Childhood Blood Lead Levels With Criminal Offending"

The title of this post is the title of this notable new research from JAMA Pediatrics published online today. The research examines what has been for some a popular theory to try to explain when violent crime increased and decreased considerable over the last half-century. As these "Key Points" reveal, the research does not support a lead-crime connection:

Question Is childhood lead exposure associated with criminal offending in a setting where the degree of lead exposure was not confounded by socioeconomic status?

Findings  In this cohort study of 553 New Zealanders observed for 38 years, lead exposure in childhood was weakly associated with official criminal conviction and self-reported offending from ages 15 to 38 years. Lead exposure was not associated with the consequential offending outcomes of a greater variety of offenses, conviction, recidivism, or violence.

Meaning  Responses toward lead exposure should focus on consequences for health, not potential consequences for crime.

The notable uptick in violent crime in the US over the last two years had seemed to significantly mute a number of earlier discussions of the prospect that reduced led exposure largely explained the major modern crime declines from 1991 through 2014. Of course, neither recent crime data in the US nor this study from New Zealand can itself conclusively prove or disprove any contestable proposition. But I am always inclined in these setting to assert that human behaviors of all sorts often defy any simple explanation.

Some prior related posts talking up lead-crime links:

December 26, 2017 at 03:26 PM | Permalink


I came to support lead as a factor in crime after the finding of higher lead levels in actual prisoners. That was the micro level linkage needed for the macro level general correlations.

I asked for an accounting of low crime levels in high lead level areas such as Egypt and China.

If you are looking for the most crimogenic substance in the world, it is alcohol. Half the murderers are drunk. Half the murder victims are legally drunk. Half the suicides are legally drunk. I have no doubt that the majority of people in domestic dispute calls are drunk. Most of the rapists and rape victims are drunk. Pathological intoxication refers to the effect of making a quiet person not want to sleep after 5 drinks but want to fight.

Two factors unify all low crime jurisdictions. Some are religious, some secular, some rich, some poor, some with high, some with low lead levels, some with high marijuana consumption, some with low, some with obesity, some with famine, some with video addiction, some with no video, some with high rates of bastardy, some with low rates of bastardy.

1) public self help, where criminals fear the neighbors more than they fear the police;

2) low lawyer/population rate, which promotes Factor No. 1. Lawyers will crush public self help to generate ineffective lawyer rent seeking jobs.

Posted by: David Behar | Dec 26, 2017 4:42:31 PM

Kevin Drum talked to one of the authors of the study and analyzes the study here: http://www.motherjones.com/kevin-drum/2017/12/new-zealand-study-provides-more-support-for-lead-crime-hypothesis/

As he notes, the study -- contra the press release -- does in fact show a correlation, even though blood-lead levels are generally lower in NZ than the US across the board.

I guess press releases are about as reliable as head notes. Useful, but still no substitute for reading the study.

Posted by: Ryan | Dec 27, 2017 2:47:06 PM

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