Childhood Lead Poisoning and its Relation to IQ

EHOH 6614Dana Baillet, Marisol Cruz, Ethan Jamison, Breanna Kawasaki, and Meredith Warman

April 2, 2014

• What is Lead?• History of Lead Use• Exposure• Consequences of Exposure• Case Studies• Reforms• How to Protect Yourself• Resources

Overview

Photo retrieved from: http://periodictable.com/Elements/082/pictures.html

• Divalent cation (2 ions)• Toxic substance

• Enzymes and proteins are distorted• Various toxic properties

• Competes with calcium for binding sites, can damage the central nervous system

• Prevents calcium from entering cells• Hinder cellular respiration• Impact the integrity of the blood-brain barrier

What is Lead (Pb)?

Needleman, H. (2004)Photo retrieved from: http://images-of-elements.com/lead.php

• Second Century B.C.: Lead used to sweeten wine• The sweetness of lead used to

balance the natural tannic flavor of wine

• Wine was an integral part of life for upper-class Romans

• Early 19th Century: Used as an insecticide in orchards

History of Lead Use

Needleman, H. (2004)Wolz, S., Fenske, R. A., Simcox, N. J., Palcisko, G., & Kissel, J. C. (2003).

• Late 19th Century: Lead based paint found to have toxic effects on children• Brisbane, Australia 1904: Lead paint used in playground

equipment linked to poor health outcomes for children• Australia: Lead banned from household use

• 1914: Lead poisoning in children first uncovered in the United States• Initial theory that lead exposure resulted in death or full

recovery • 1970s: Further research links lead poisoning to

impaired cognitive function in children

Lead Based Paint

Needleman, H. (2004)

• Most lead poisoning in children now is due to dust and chips from deteriorating paint

• Dust and soil from airborne lead in gasoline and dust from paint (playing in contaminated soil)

• Lead can cross the placenta and be in breast milk• Other possible sources

How are Children Exposed to Lead?

Jacobs DE, Clickner RP, Zhou JY, et al. (2002); Lanphear, Matte, Rogers, et al. (1998); CDC (2002)

• Early symptoms• Chronic fatigue• Irritability• Loss of appetite• Stomach discomfort/constipation• Low attention span• Insomnia

Health Effects of Lead Exposure

US EPA ( 2013)

• Brain and nervous system damage• Reduced IQ• Learning disabilities• Mental retardation

• Behavioral problems• Hyperactivity• Developmental delays• Anemia

• Liver and kidney damage• Hearing loss• Coma or Death

(in extreme cases)

Long Term Consequences

US EPA ( 2014); NSC (2009)

• Deficits found at blood lead levels (BLL) of <7.5 μg/dL

• More severe deficits occur at lower BLL

• No apparent threshold for cognitive impairment

• Prenatal exposure to lead impacts cognitive development

Long Term Consequences: IQ

Lanphear (2005); Meyer (2008)

Impact of Low Blood Lead Concentrations on IQ and School Performance in Chinese Children

Case Study 1

• Objective: Relationship between blood lead concentrations, children’s IQ, and school performance

• Overview:• 1341 children (738 boys and 603 girls) from Jintan,

China• Blood lead concentrations were measured when

children were 3–5 years old• IQ was assessed using the Primary Scale of

Intelligence• School performance was assessed by standardized

tests on 3 major subjects (Chinese, math, and English) when children were 8–10 years old

Case Study 1

Liu et al. (2013)

• Conclusion:• Blood lead concentrations in early childhood, even

<10 μg/dL, have a long-term negative impact on cognitive development

• Compared to children with blood lead concentrations <8 μg/dL, those with blood lead concentrations ≥ 8 μg/dL scored 2–3 points lower in IQ and 5–6 points lower in school tests

• No significant differences in IQ or school tests between children with blood lead concentrations groups 8–10 and ≥ 10 μg/dL

Case Study 1

Case Study 2

Early Childhood Lead Exposure & Academic Achievement: Evidence From Detroit Public Schools, 2008–2010

• Objective: Long-term effects of early childhood lead exposure on academic achievement among children in Detroit Public Schools

• Overview:• Linked early childhood blood lead testing surveillance

data from the Detroit Department of Health and Wellness Promotion to educational testing data from elementary and junior high school students

• Used data to investigate the effect of early childhood lead exposure on academic achievement among these children

• Data adjusted for grade level, gender, race, language, maternal education, and socioeconomic status

Case Study 2

Zhang et al. (2013)

• Conclusion:• High blood lead levels before age 6 were strongly

associated with poor academic achievement in grades 3, 5, and 8

• Negatively associated with academic achievement in elementary and junior high school, after adjusting for key potential confounders

• The control of lead poisoning should focus on primary prevention of lead exposure in children

• Need for development of special education programs for students with lead poisoning

Case Study 2

• 1978: Lead-based paint banned for consumer use• Environmental Protection Agency’s (EPA) New

Renovation, Repair, and Painting Rule• 1988: Toxic Substances Control Act• 1992: Lead Disclosure Rule• 1999: Lead-Safe Housing Rule• 2008: Consumer Product Safety Act• Colorado Blood Lead-Level testing• 2012: Centers for Disease Control and Prevention

(CDC) Update Blood Lead Levels

Reforms

CDC (2012)

• Key of protection: preventing or eliminating exposure• Know the history of your home (constructed before

1978?)• First step: Getting your child’s blood lead levels tested• Next: Identify possible points of exposure

• Paint, water, dust, soil, etc.

How to Protect Yourself and Your Children

CDC (2005); CDPHE (2013); Lanphear (1998)

• Lead abatement can be done by contractors to reduce lead sources in your home

• Parents should work at reducing childhood exposure to paint chips or dust

• Not allowing your child to eat dirt or mouth metal objects

• Give children foods rich in iron, vitamin C, and calcium

• Use only cold water from the tap for drinking and cooking

• Home test kits: see paint section in hardware stores

How to Protect Yourself and Your Children

CDC (2005); Lanphear (1998

• The Colorado Department of Public Health and Environment has in-state authority to regulate lead under the Clean Air Act

• The Air Pollution Control Division certifies lead contractors for abatement and home inspection

• Federal regulations require all realtors to warn/notify new residents of lead hazards

• Colorado state regulations require renovators to distribute an EPA-approved lead hazard information pamphlet prior to any work in homes built before 1978

Local Resources

CDPHE (2013)

• Lead poisoning in children continues to be an important global public health issue

• CDC considers lead poisoning the most preventable environmental disease among young children

• There are many way to test for lead and to protect your children from exposure

Conclusion

• Centers for Disease Control and Prevention. Managing Elevated Blood Lead Levels Among Young Children: Recommendations From the Advisory Committee on Childhood Lead Poisoning Prevention. Atlanta, GA: Centers for Disease Control and Prevention; 2002. Available at:www.cdc.gov/nceh/lead/CaseManagement/caseManage_main.htm. Accessed February 20th, 2014

• Centers for Disease Control and Prevention. Preventing Lead Poisoning in Young Children A Statement by the Centers for Disease Control and Prevention. Atlanta, GA: Centers for Disease Control and Prevention; 2005. Available at: http://www.cdc.gov/nceh/lead/publications/prevleadpoisoning.pdf Accessed February 26th, 2014

• Colorado Department of Health and Environment. Lead Safety Time. Colorado Department of Health and Environment Informational Pamphlet. Colorado 2013. Available at: http://www.colorado.gov/cs/Satellite/CDPHE-AP/CBON/1251594599618 Accessed February 26th 2014

• Jacobs DE, Clickner RP, Zhou JY, et al. The prevalence of lead-based paint hazards in U.S. housing. Environ Health Perspect.2002;110 :A599– A606

• Lanpher, Bruce P. Burgoon, David A. Rust, Steven w. Eberly, Shirley. Galke, Warren. Environmental Exposures to Lead and Urban Children’s Blood Lead Level. Environmental Research, Section A 78,120-130 1998. Available at: http://www.ncbi.nlm.nih.gov/pubmed/9515067 Accessed February 26th, 2014

• Lanphear, Bruce P., Hornung, Richard, Khoury, Jane, Yolton, Kimberly, Baghurst, Peter, Bellinger, David C., . . . Roberts, Russell. (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

• Lanphear BP, Matte TD, Rogers J, et al. The contribution of lead-contaminated house dust and residential soil to children's blood lead levels. A pooled analysis of 12 epidemiologic studies. Environ Res.1998;79 :51– 68

• Liu, J., Li, L., Wang, Y., Yan, C., & Liu, X. (2013). Impact of low blood lead concentrations on IQ and school performance in Chinese children. PLoS One, 8(5), e65230.

• Meyer, P. A., Brown, M. J., & Falk, H. (2008). Global approach to reducing lead exposure and poisoning. Mutat Res, 659(1-2), 166-175. doi: 10.1016/j.mrrev.2008.03.003

• Zhang, N., Baker, HW.., Tufts, M., Raymond, R.E., Salihu, H. and Michael R. Elliott. Early Childhood Lead Exposure and Academic Achievement: Evidence From Detroit Public Schools, 2008–2010. AJPH: March 2013, Vol. 103, No. 3, pp. e72-e77.

• National Safety Council. (2009). LeadPoisoning Fact Sheet. http://www.nsc.org/news_resources/Resources/Documents/Lead_Poisoning.pdf

• Needleman, H. (2004). Lead Poisoning. Annual Review of Medicine, 55, 209-222.• United States Environmental Protection Agency. (2014, Feb. 20, 2014). Lead. Retrieved Feb. 2014, from http://www2.epa.gov/lead• Wolz, S., Fenske, R. A., Simcox, N. J., Palcisko, G., & Kissel, J. C. (2003). Reidential Arsenic and Lead Levels in an Agricultural Community

with a History of Lead Arsenate Use. Environmental Research, 93, 293-300.

References