Use of Geographic Information System Technology to Aid Health Department Decision Making about Childhood Lead Poisoning Prevention Activities

Article excerpt

The Centers for Disease Control and Prevention recommend that local public health agencies use local data to identify children at risk for lead exposure to ensure that they receive preventive services. The objective of this study was to demonstrate the usefulness of a geographic information system (GIS) in identifying children at risk for lead exposure. We conducted a descriptive study, using GIS technology, of the blood lead (BPb) levels and residential location of at-risk children screened for lead exposure. "At-risk children" were defined as those children living in housing built before 1950 or in an area with a high proportion of older housing. The study was conducted in Jefferson County, Kentucky, USA. Participants were the cohort of children born in 1995 and screened from 1996 through 1997, and children younger than age 7 years who were screened from 1994 through 1998. Outcome measures were the BPb level and residential location (address or target zone) of at-risk children screened from 1996 through 1997, and the number and location of homes where more than one child had been poisoned by lead from 1994 through 1998. The proportion of children screened who live within zones targeted for universal screening varied from 48% to 53%, while only 50% of the at-risk children in the entire county were screened. Between 1994 and 1998, 79 homes housed 35% of the 524 children with lead poisoning. These housing units were prioritized for lead-hazard remediation. Significant numbers of at-risk children throughout the county were not being tested for lead exposure, even in prioritized areas. GIS can be very useful to health departments in planning lead exposure screening strategies and measuring program performance. Key words: childhood, geographic information systems, lead poisoning, public health. Environ Health Perspect 109:89-94 (2001). [Online 21 December 2000]

Recent data from phase 2 of the Third National Health and Nutrition Examination Survey (NHANES III) indicate that 4.4% of U.S. children younger than 6 years of age have blood lead (BPb) levels of at least 10 [micro]g/dL, the level associated with cognitive impairment and behavior problems (1). NHANES III data demonstrate that residence in older housing is a strong, independent risk factor for lead poisoning. Deteriorating lead-based house paint remains the most important source of lead exposure for children in the United States (2). Before 1950, house paint contained up to 50% lead by weight, and currently children in 26 million households live in housing built before 1950 (3). The children most at risk for lead exposure are 6 months to 2 years of age, who are exposed primarily by ingestion of lead-contaminated dust on objects or hands placed in their mouths (2).

The U.S. Public Health Service has a strategic plan to eradicate childhood lead poisoning by the year 2011 (4). The plan requires that at-risk children be screened by blood tests for lead exposure. Children with mildly elevated BPb levels (e.g., 10-19 [micro]g/dL) can then be protected from further lead exposure if parents are taught to reduce exposure. In addition, children with higher BPb levels (e.g., at least 20 [micro]g/dL) can receive medical evaluation and treatment, if indicated. Because the risk for lead exposure is not distributed evenly throughout the population, the Centers for Disease Control and Prevention (CDC) recommended in 1997 that health departments use local data to identify children and neighborhoods at high risk in order to target screening efforts (2). For example, the CDC suggested that health departments could target children ages 6 months to 2 years who reside in geographic areas, such as zip codes or census tracts, where at least 27% of the housing stock was constructed before 1950.

This paper describes how a computerized geographic information system (GIS) can be used to help health department decision making and program evaluation about screening for childhood lead exposure when the main criterion used to assess a child's risk of lead exposure is residence in housing constructed before 1950 (5). …