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Childhood Lead Poisoning Prevention

Principal Investigator(s): 

Dr. Kanarek works with the Wisconsin Department of Health Services (DHS) on several childhood lead poisoning prevention projects. Childhood lead poisoning has been a recognized as a major public health issue for over a century. Since the ban on lead in paint, gasoline and other consumer products in the 1970s, blood lead levels (BLL) in children and adults has decreased markedly; new sources of lead to the environment have been virtually eliminated in the United States. However, lead exposure still occurs today due to lead’s varied uses and its persistence in the environment. The statewide prevalence of lead poisoning in Wisconsin [defined by the Centers for Disease Control and Prevention and Wisconsin Statute as blood lead levels above 10μg/dl] for children under two years of age who have been screened is 2.6%, more than twice the national prevalence. Further, approximately five percent of children who entered the Wisconsin public school system in 2006 have been lead poisoned. However, state public health interventions are mandated only for children with elevated blood lead levels (eBLL), defined as 20 μg/dl or greater. Despite evidence of the deleterious health effects of lead exposure at and below 10μg/dl, there are no state mandated interventions or secondary prevention efforts targeted to this group. One major concern with childhood lead poisoning is that children adversely affected by early exposure to lead do not generally have sequelae that would lead to treatment within a health-system context. For example, the relationship between increased BLL and decreased cognitive abilities, as measured by IQ scores, have been documented for decades and is well accepted by the scientific community. Therefore, the cognitive and behavioral issues associated with lead poisoning are more likely to manifest in educational settings, and may be indicated by low test scores, enrollment in special education programs, high rates of absenteeism, and behavioral problems within the classroom. The newest project of this PHS- DHS collaborative research project is to investigate the association of moderate blood lead levels (10 – 20 μg/dl) and educational achievement of elementary school children in Wisconsin. Currently, an “elevated blood lead level” is defined as a single venous result of greater than or equal to 20 μg/dl, or persistent levels of 15 μg/dl or greater. Although extensive research has been conducted with regard to lead exposure and cognitive impairment, there have been no studies conducted in the United States that examine early childhood lead exposure and educational achievement in a school setting. We hypothesize that cognitive effects, as measured by statewide educational proficiency examinations, at these currently monitored, yet untreated, levels will have an inverse relationship to blood lead levels measured in early childhood. This study will be conducted as a matched case-control analysis; study subjects will be identified and selected from the state’s lead surveillance database. Cases will be defined as children who have had a BLL between 10 – 20 μg/dl before the child’s second birthday. Controls will be defined as children who have been tested for lead at one and two years of age, and have had reported blood lead level of 0 μg/dl. Cases and controls will be matched on age, gender, race, program participation (i.e. WIC, Medicaid), and school district. The primary outcome for the analysis will be study subject’s scores on 4th grade administration of the Wisconsin Knowledge and Concepts Exams statewide assessment. Additional outcome data collected by DPI, such as absenteeism, grade retention, expulsion and classroom behavioral conduct, may be used as secondary outcomes in this analysis.