Estimated IQ points and lifetime earnings lost to early childhood blood Lead levels in the United States

Cognitive and Behavioral Manifestations of Lead

Cognitive and Behavioral Abnormalities of Pediatric Diseases ◽

10.1093/oso/9780195342680.003.0071 ◽

2010 ◽

Author(s):

Hugh L. Evans

Keyword(s):

United States ◽

Blood Lead ◽

The United States ◽

Conduct Disorders ◽

Lead Content ◽

Blood Lead Levels ◽

Toxic Exposure ◽

Postnatal Exposure ◽

Household Dust ◽

Lead Levels

The link between exposure to lead and children’s cognitive problems was implied in the earliest medical reports of frank lead poisoning of young children in Australia in the 1800s (Lin-Fu 1992). Children with acute severe toxicity of lead (Pb) are now rarely seen in the United States. However, millions of children may have subclinical neurobehavioral disorders associated with chronic low-level exposure to lead, representing a major public health concern (Bellinger 2008a). Lead is a nonessential metal that is recognized as a source of toxic exposure, with the developing nervous system particularly vulnerable. Because of this, U.S. regulations limiting the lead content of gasoline and household paint have led to a gradual reduction of the average blood lead concentration of Americans over the last three decades. Average blood lead levels of children in the United States dropped an estimated 78% from 1976 to 1991 (Brody et al. 1994; Caldwell et al. 2009). Despite these reductions in exposure to lead, new advances in research techniques have documented harmful consequences associated with lower blood lead levels. This raises the possibility that there is no threshold for occurrence of lead-induced toxicity. Bellinger (2008a) refers to “the silent pandemic of neurodevelopmental disorders resulting from children’s continuing exposure to low levels of lead.” The developing brain may be more sensitive to exposure to lead than the adult. Since the pioneering work of Needleman and colleagues (1979), a large scientific literature has documented the deleterious effects of pre- and neonatal exposure to lead. Decrements in IQ scores have proven to be among the most sensitive and consistent consequences of a child’s exposure to lead, but other cognitive and behavioral changes have been described as well, including attention-deficit hyperactivity disorder (ADHD). Among the important current sources of children’s exposure to lead is household dust (Dixon et al. 2009) the lead content in old water pipes, batteries, and from contamination by numerous industrial processes. Pre and postnatal exposure to cigarette smoke is a cofactor with lead exposure in children’s conduct disorders (Braun et al. 2008). Diagnosis of lead-induced disorders involves the determination of exposure to lead and the atomic absorption assay of lead in whole blood.

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Demographic and Socioeconomic Factors Associated with Blood Lead Levels among Mexican-American Children and Adolescents in the United States

Public Health Reports ◽

10.1177/003335490512000412 ◽

2005 ◽

Vol 120 (4) ◽

pp. 448-454 ◽

Cited By ~ 28

Author(s):

Leo S. Morales ◽

Peter Gutierrez ◽

Jose J. Escarce

Keyword(s):

United States ◽

Drinking Water ◽

Mexican American ◽

Family Income ◽

Blood Lead ◽

The United States ◽

Blood Lead Levels ◽

Mexican American Youth ◽

Lead Levels ◽

American Children

Objective. This study was designed to assess demographic and socioeconomic differences in blood lead levels (BLLs) among Mexican-American children and adolescents in the United States. Methods. We analyzed data from the Third National Health and Nutrition Examination Survey, 1988–1994, for 3,325 Mexican-American youth aged 1 to 17 years. The main study outcome measures included a continuous measure (μg/dL) of BLL and two dichotomous measures of BLL (⩾5 μg/dL and ⩾10 μg/dL). Results. The mean BLL among Mexican-American children in the United States was 3.45 μg/dL (95% confidence interval [CI] 3.07, 3.87); 20% had BLL ⩾5 μg/dL (95% CI 15%, 24%); and 4% had BLL ⩾10 μg/dL (95% CI 2%, 6%). In multivariate analyses, gender, age, generational status, home language, family income, education of head of household, age of housing, and source of drinking water were statistically significant independent predictors ( p<0.05) of having higher BLLs and of having BLL ⩾5 μg/dL, whereas age, family income, housing age, and source of drinking water were significant predictors ( p<0.05) of having BLL ⩾10 μg/dL. Conclusions. Significant differences in the risk of having elevated BLLs exist among Mexican-American youth. Those at greatest risk should be prioritized for lead screening and lead exposure abatement interventions.

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