Lead–crime hypothesis

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This warning on an old Lynnwood, Washington fuel pump notes how it used to dispense gasoline with tetraethyllead additives.

The lead–crime hypothesis is the proposed link between elevated blood lead levels in children and increased rates of crime, delinquency, and recidivism later in life[1][2][3][4].

Lead is widely understood to be highly toxic to multiple organs of the body[5], particularly the brain[6][7][8]. Individuals exposed to lead at young ages may be more vulnerable to learning disabilities[9][10], decreased I.Q.[11], attention deficit hyperactivity disorder[12][13], and problems with impulse control[14], all of which may be negatively impacting decision making and leading to the commission of more crimes as these children reach adulthood, especially violent crimes[15].

The major source of lead exposure during the 20th century was leaded gasoline. Proponents of the lead–crime hypothesis argue that the removal of lead additives from motor fuel, and the consequent decline in children's lead exposure, explains the fall in crime rates in the United States beginning in the 1990s.[16] This hypothesis also offers an explanation of the earlier rise in crime in the preceding decades as the result of increased lead exposure throughout the mid-20th century.[17]

The lead–crime hypothesis is not mutually exclusive with other explanations of the drop in US crime rates such as the legalized abortion and crime effect.[17] The difficulty in measuring the effect of lead exposure on crime rates is in separating the effect from other indicators of poverty such as poorer schools, nutrition, and medical care, exposure to other pollutants, and other variables that may lead to crime.[16]

Background[edit]

Lead, a naturally occurring metal of bluish-grey color, has been used for multiple purposes in the history of human civilization. Advantages include being somewhat soft and pliable as well as resistant to corrosion compared to other metals. The widespread substance is also able to function as a shield against various forms of radiation.[18]

Expanded scientific investigation into organolead chemistry and the varied ways in which human biology changes due to lead exposure took place throughout the 20th century. Although it has continued to be in wide use even into the 21st century, greater understanding of blood lead levels (BLLs) and other factors have meant that a new scientific consensus has emerged. No 'safe' level of lead in the human bloodstream exists as such; any amount can contribute to neurological problems and other health issues.[18]

Medical analysis of the role of lead exposure in the brain note increases in impulsive actions and social aggression as well as the possibility of developing attention deficit hyperactivity disorder (ADHD). Those conditions likely influence personality traits and behavioral choices, with examples including having poor job performance, beginning a pattern of substance abuse, and undergoing teenage pregnancy. Evidence that lead exposure contributes to lower intelligence quotient (IQ) scores goes back to a seminal 1979 study in Nature, with later analysis finding the link particularly robust.[18][19]

The international process of trying to lower the prevalence of lead has been largely spearheaded by the Partnership for Clean Fuels and Vehicles (PCFV). The non-governmental organization partners with major oil companies, various governmental departments, multiple civil society groups, and other such institutions worldwide. Efforts to phase-out lead in transport fuel achieved major gains in over seventy-five nations. In discussions at the 2002 'Earth Summit', institutions under the umbrella of the United Nations vowed to emphasize public–private partnerships (PPPs) in order to help developing and transitional countries go unleaded.[20]

Research on lead–crime correlation[edit]

After decades of relatively steady increases, crime rates in the United States started to sharply decline in the 1990s. The trend continued into the new millennium. Multiple possible explanations have come about, with academic studies pointing to complex, multifactorial causation as different social trends occurred at the same time.[19] The fact that in the United States anti-lead efforts took place simultaneously alongside falls in violent crime rates attracted attention from researchers. Changes were not uniform across the country, even while increasingly stringent Environmental Protection Agency rules went into force from 1970s onward. Several areas had far greater lead exposure compared to others for years.[19]

According to Jessica Wolpaw Reyes of Amherst College, between 1992 and 2002 the phase-out of lead from gasoline in the U.S. "was responsible for approximately a 56% decline in violent crime". While cautioning that the findings relating to "murder are not robust if New York and the District of Columbia are included," Wolpaw Reyes concluded: "Overall, the phase-out of lead and the legalization of abortion appear to have been responsible for significant reductions in violent crime rates." She additionally speculated that by "2020, all adults in their 20s and 30s will have grown up without any direct exposure to gasoline lead during childhood, and their crime rates could be correspondingly lower."[19] According to Reyes, "Childhood lead exposure increases the likelihood of behavioral and cognitive traits such as impulsivity, aggressivity, and low IQ that are strongly associated with criminal behavior".[19]

Brazilian-German economist Achim Steiner, speaking as then head of the U.N. Environment Programme, described anti-lead efforts as a key sustainable development success.[citation needed]

A 2011 study by the California State University found that "Ridding the world of leaded petrol, with the United Nations leading the effort in developing countries, has resulted in $2.4 trillion in annual benefits, 1.2 million fewer premature deaths, higher overall intelligence and 58 million fewer crimes", according to the United Nations News Centre.[20] The executive director of the United Nations Environment Programme (UNEP) Achim Steiner argued that "Although this global effort has often flown below the radar of media and global leaders, it is clear that the elimination of leaded petrol is an immense achievement on par with the global elimination of major deadly diseases."[20]

According to a May 2017 study, lead exposure in childhood substantially increased school suspensions and juvenile detention among boys in Rhode Island, suggesting that the phasing out leaded gasoline may explain a significant part of the decline in crime in the United States beginning in the 1990s.[16][21]

See also[edit]

References[edit]

  1. ^ Stretesky, Paul B.; Lynch, Michael J. (2004). "The Relationship between Lead and Crime". Journal of Health and Social Behavior. 45 (2): 214–229. doi:10.1177/002214650404500207. ISSN 0022-1465.
  2. ^ Nevin, Rick (2007). "Understanding international crime trends: The legacy of preschool lead exposure". Environmental Research. 104 (3): 315–336. doi:10.1016/j.envres.2007.02.008. ISSN 0013-9351.
  3. ^ Marcus, David K.; Fulton, Jessica J.; Clarke, Erin J. (2010-02-26). "Lead and Conduct Problems: A Meta-Analysis". Journal of Clinical Child & Adolescent Psychology. 39 (2): 234–241. doi:10.1080/15374411003591455. ISSN 1537-4416.
  4. ^ Wright, John Paul; Dietrich, Kim N; Ris, M. Douglas; Hornung, Richard W; Wessel, Stephanie D; Lanphear, Bruce P; Ho, Mona; Rae, Mary N (2008-05-27). "Association of Prenatal and Childhood Blood Lead Concentrations with Criminal Arrests in Early Adulthood". PLoS Medicine. 5 (5): e101. doi:10.1371/journal.pmed.0050101. ISSN 1549-1676.
  5. ^ ATSDR. "Lead (Pb) Toxicity: Key Concepts | ATSDR - Environmental Medicine & Environmental Health Education - CSEM". www.atsdr.cdc.gov. Retrieved 2018-10-18.
  6. ^ Stewart, W. F.; Schwartz, B. S.; Davatzikos, C.; Shen, D.; Liu, D.; Wu, X.; Todd, A. C.; Shi, W.; Bassett, S. (2006-05-22). "Past adult lead exposure is linked to neurodegeneration measured by brain MRI". Neurology. 66 (10): 1476–1484. doi:10.1212/01.wnl.0000216138.69777.15. ISSN 0028-3878.
  7. ^ Cecil, Kim M; Brubaker, Christopher J; Adler, Caleb M; Dietrich, Kim N; Altaye, Mekibib; Egelhoff, John C; Wessel, Stephanie; Elangovan, Ilayaraja; Hornung, Richard (2008-05-27). "Decreased Brain Volume in Adults with Childhood Lead Exposure". PLoS Medicine. 5 (5): e112. doi:10.1371/journal.pmed.0050112. ISSN 1549-1676.
  8. ^ Sanders, T.; Liu, Y.; Buchner, V.; Tchounwou, P.B. (January 2009). "Neurotoxic Effects and Biomarkers of Lead Exposure: A Review". Reviews on Environmental Health. 24 (1). doi:10.1515/reveh.2009.24.1.15. ISSN 2191-0308.
  9. ^ Leviton, A.; Bellinger, D.; Allred, E.N.; Rabinowitz, M.; Needleman, H.; Schoenbaum, S. (1993). "Pre- and Postnatal Low-Level Lead Exposure and Children′s Dysfunction in School". Environmental Research. 60 (1): 30–43. doi:10.1006/enrs.1993.1003. ISSN 0013-9351.
  10. ^ Caito, Samuel; Aschner, Michael (2017), "Developmental Neurotoxicity of Lead", Advances in Neurobiology, Springer International Publishing, pp. 3–12, ISBN 9783319601885, retrieved 2018-10-12
  11. ^ Lanphear, Bruce P.; Hornung, Richard; Khoury, Jane; Yolton, Kimberly; Baghurst, Peter; Bellinger, David C.; Canfield, Richard L.; Dietrich, Kim N.; Bornschein, Robert (2005). "Low-Level Environmental Lead Exposure and Children's Intellectual Function: An International Pooled Analysis". Environmental Health Perspectives. 113 (7): 894–899. doi:10.1289/ehp.7688. ISSN 0091-6765.
  12. ^ P., Braun, Joe M. Kahn, Robert S. Froehlich, Tanya Auinger, Peggy Lanphear, Bruce (2006). Exposures to Environmental Toxicants and Attention Deficit Hyperactivity Disorder in U.S. Children. National Institute of Environmental Health Sciences. OCLC 678275247.
  13. ^ Bellinger, David C (2008-05-27). "Neurological and Behavioral Consequences of Childhood Lead Exposure". PLoS Medicine. 5 (5): e115. doi:10.1371/journal.pmed.0050115. ISSN 1549-1676.
  14. ^ Liu, Jianghong (2011). "Early health risk factors for violence: Conceptualization, evidence, and implications". Aggression and Violent Behavior. 16 (1): 63–73. doi:10.1016/j.avb.2010.12.003. ISSN 1359-1789.
  15. ^ Olympio, Kelly Polido Kaneshiro; Gonçalves, Claudia; Günther, Wanda Maria Risso; Bechara, Etelvino José Henriques (2009). "Neurotoxicity and aggressiveness triggered by low-level lead in children: a review". Revista Panamericana de Salud Pública. 26 (3). doi:10.1590/s1020-49892009000900011. ISSN 1020-4989.
  16. ^ a b c Doleac, Jennifer L. (1 June 2017). "New evidence that lead exposure increases crime". The Brookings Institution.
  17. ^ a b Steel, Daniel (2013). "Mechanisms and Extrapolation in the Abortion-Crime Controversy". In Chao, Hsiang-Ke; et al. Mechanism and Causality in Biology and Economics. Springer Science & Business Media. p. 188. ISBN 978-9-40-072454-9.
  18. ^ a b c Dapul, Dr. Heda; Laraque, Dr. Danielle (August 2014). "Lead Poisoning in Children". Advances in Pediatrics. 61 (1): 313–333. Retrieved 30 November 2016.
  19. ^ a b c d e Reyes, Jessica Wolpaw (2007). "Environmental Policy as Social Policy? The Impact of Childhood Lead Exposure on Crime" (PDF). The B.E. Journal of Economic Analysis & Policy. 7 (1). Retrieved 30 November 2016.
  20. ^ a b c "Phase-out of leaded petrol brings huge health and cost benefits – UN–backed study". United Nations News Centre. 27 October 2011.
  21. ^ Aizer, Anna; Currie, Janet (May 2017). "Lead and Juvenile Delinquency: New Evidence from Linked Birth, School and Juvenile Detention Records". NBER Working Paper No. 23392. Cambridge, Mass: National Bureau of Economic Research. doi:10.3386/w23392.

Further reading[edit]

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