Use of geographic information system technology to aid Health Department decision making about childhood lead poisoning prevention activities

Using blood lead concentrations of wildlife sentinels to identify environmental risk factors of lead exposure for public health and wildlife rehabilitation efforts

Lead poisoning remains a persistent health issue for both humans and wildlife, despite strides to reduce lead contamination in the environment. Using Geographic Information Systems (GIS), this study explores the associations between blood lead levels (BLLs) in wildlife sentinels and possible built environment lead exposure risk factors in the Minneapolis-Saint Paul, Minnesota urban area. Results show a high-level of heterogeneity in animal BLLs (n = 472) across our urban environment and suggest that each kilometer increase in road density is associated with a 17.07% (95% CI: 1.48%, 35.05%) increase in BLL in our study species of Virginia opossums and Eastern gray squirrels, and a 14.28% (95% CI: 1.16%, 29.09%) increase in BLL of rock pigeons. For squirrels and opossums, we see an additional 5.72% (95% CI: 0.59%, 10.85%) increased risk of BLL for every 1000 people per square-mile. The relationship between animal sentinels and environmental hazards can give us an insight into the potential lead exposure risks for humans. The use of wildlife sentinel data to explore environmental risk factors supports a One Health approach to better address public health questions and aid in wildlife rehabilitation related to residual lead poisoning from ambient environmental exposures.

Neighborhood disparities and the burden of lead poisoning

BACKGROUND

To assess the persistence of neighborhood-level lead poisoning disparities in Rhode Island.

METHODS

Rhode Island Department of Health blood lead levels (BLL) collected from 2006-2019 were linked to census block group rates of poverty and housing built pre-1950. We computed multivariate logistic regression models of elevated BLLs (≥5 µg/dL and ≥10 µg/dL).

RESULTS

Of the 197,384 study children, 12.9% had BLLs ≥5 µg/dL and 2.3% had BLLs ≥10 µg/dL. The proportion of children with BLL ≥ 5 µg/dL increased across quintiles of poverty and old housing. The odds ratio for highest quintiles was 1.44 (95% CI: 1.29, 1.60) and 1.92 (95% CI: 1.70, 2.17) for poverty and pre-1950 housing, respectively. A significant temporal decline was observed for BLL ≥ 5 µg/dL (2006: 20.5%, 2019: 3.6%). Disparities narrowed over the study period across quintiles of poverty and old housing with a similar trend appearing in the proportion of children with BLL ≥ 10 µg/dL.

CONCLUSION

Despite tremendous progress in reducing lead exposure, substantial neighborhood disparities in lead poisoning persist. These findings provide valuable considerations for primary childhood lead exposure prevention.

IMPACT

Through linkage of Rhode Island Department of Health childhood lead poisoning and census data, this study captures neighborhood-level disparities in lead poisoning from 2006-2019. This study demonstrates that the odds of lead poisoning increased in a stepwise fashion for neighborhood quintiles of poverty and housing built pre-1950. While the magnitude of lead poisoning disparities narrowed across quintiles of poverty and old housing, disparities persist. Children's exposure to sources of lead contamination continues to be an important public health concern. The burden of lead poisoning is not equally distributed among all children or communities.

’As safe as houses; the risk of childhood lead exposure from housing in England and implications for public health’

BACKGROUND AND AIM

Exposure to lead can harm a child's health, including damage to the nervous system, delayed growth, hearing loss, and many other adverse health effects, as well as implications for social, economic, educational and social well-being. Lead exposure in children is still a concern and cases require public health management to find the exposure source and interrupt the exposure pathway. Housing characteristics can indicate the presence of lead-contaminated paint and leaded water supply pipes. We aimed to explore the relationship between housing characteristics and elevated blood lead concentration (BLC) in children in England.

METHODS

We used a retrospective cohort design and included all cases of lead exposure in children reported to the UK Health Security Agency between 2014 and 2020 via surveillance. A case was a child aged under 16 years, resident in England, BLC of ≥ 0.48 μmol/L (10 µg/dL) and referred for public health management. We collected case demographic details and housing characteristics (age and type). We explored associations between elevated BLC and risk factors, using generalised linear mixed effects models and compared cases' housing type to that expected nationally.

RESULTS

Two hundred and sixty-six out of 290 cases met the case definition. There was no difference in BLCs between genders, age groups, deprivation, and housing type. After adjusting for reporting source, housing age and type, cases residing in housing built pre-1976 had a BLC of 0.32 (95%CI 0.02, 0.63) µmols/L (6.63 (95%CI 0.42, 13.0) µg/dL) higher than cases living in housing built after this time. Cases were 1.68 times more likely to be living in terraced housing (housing adjoined to one another) than other children and less likely to live in apartments and detached properties.

CONCLUSION

This study suggests an association between housing characteristics and BLC in children. Housing age and type may act as a proxy for lead exposure risk through exposure to leaded paint, lead water pipes, and lead contaminated dust from indoor and outdoor sources. Public health action should consider targeting families more at risk in older housing by raising awareness of the potential presence of lead pipes and paint. Interventions should include working with wider stakeholders including other housing and environmental professionals, the private sector, as well as parents and carers.

A new screening index to better target low-level lead exposure in Atlanta, Georgia

Lead poisoning is often seen as a problem of the past. While acute cases are now rare, there is no known safe level of lead for children and blood lead levels at and below 5 μg/dL are associated with neurological deficits. Previous work has established that risk factors for lead exposure include race/ethnicity, poverty, Medicaid enrollment, housing built before 1950, and age. Efficient blood lead screening is crucial in the greater Atlanta area as pockets of poverty and old housing put some children at particularly high risk for chronic exposure to low levels of lead. Here, 20 years of data on children’s blood lead levels in Georgia were used to create maps to assess the spatial distribution of blood lead screening and blood lead levels in the Atlanta area. ZIP code tabulation area (ZCTA)-level screening rates continue to be associated with relative poverty but not with housing age, a well-established risk factor for lead exposure. Building on previous research, a priority screening index based on poverty and housing age was also created to identify specific high-risk census tracts for screening within Atlanta ZCTAs. This index shows a total of 18 highest-priority census tracts in the greater Atlanta area. Together, these 18 tracts contain 2715 children under six years old, 1.7% of all children under six years old in the entire greater Atlanta area.

Toxic structures: Speculation and lead exposure in Detroit's single-family rental market

Foreclosure sales permitted investors to purchase large volumes of low-cost residential properties after the last financial crisis, reshaping patterns of property ownership in low-income housing markets across the US. This study links post-foreclosure property acquisitions by investor landlords to subsequent lead poisoning cases among children under age six living in Detroit, Michigan. We find that the odds of exhibiting elevated blood lead levels (≥5 μg/dL) are higher for children living in investor-owned homes purchased through tax foreclosure sale. These findings highlight the potential for property speculation in post-foreclosure housing markets to exacerbate severe and racialized burdens of excess lead toxicity in low-income communities.

Childhood lead poisoning from domestic products in China: A case study with implications for practice, education, and policy

OBJECTIVE

This study aimed to report three representative childhood lead poisoning cases in China from domestic products exposure and to highlight their critical implications for practice, education, and policy in prevention and treatment of childhood lead poisoning by health care providers, especially public health nurses.

DESIGN AND SAMPLE

Three representative childhood lead poisoning cases occurring in 2017 were collected and analyzed.

RESULTS

The lead exposure sources of three cases were evaluated by experts in the field and determined to be tin pots, home factories for tinfoil, and contamination of folk medicine, respectively. These cases demonstrated that the lack of lead exposure risk assessment, insufficient knowledge of potential lead exposure sources, underdeveloped policy, and regulations were areas for improvement.

CONCLUSIONS

The best strategies for preventing lead poisoning include an appropriate risk assessment of lead exposure, implementation of comprehensive parental health education, conduction of further research by public health providers, and the application of policy strategies by the government. It was determined that public health nurses are at the frontline of prevention of lead poisoning in children.

Variability in the spatial density of vacant properties contributes to background lead (Pb) exposure in children

BACKGROUND

Heightened blood lead levels (BLL) are associated with cognitive deficiencies and adverse behavioral outcomes. Lead-contaminated house dust is the primary source of exposure in U.S. children, and evidence suggests that even background (low-level) exposure has negative consequences. Identifying sources of background exposure is of great public health significance because of the larger number of children that can be affected.

METHODS

Blood lead was assessed in a bi-racial sample of children from Syracuse, NY, aged 9-11, using established biomonitoring methods. The spatial density of vacant properties was modelled from publicly available georeferenced datasets. Further, regression models were used to measure the impact of this spatial density variable on children's BLL.

RESULTS

In a sample of 221 children, with a mean BLL of 1.06 µg/dL (SD = 0.68), results showed increases in spatial density of vacant properties predict increases in median blood-PB levels, b = 0.14 (0.06-0.21), p < .001. This association held true even after accounting for demographic covariates, and age of individual housing. Further analysis showed spatial autocorrelation of the residuals changed from a clustered pattern to a random pattern once the spatial density variable was introduced to the model.

DISCUSSION

This study is the first to identify a background-lead exposure source using spatial density modelling. As vacant properties deteriorate, lead-contaminated dust likely disperses into the surrounding environment. High-density areas have an accumulation of lead hazards in environmental media, namely soil and dust, putting more children at risk of exposure.

Analysis of Pollution Hazard Intensity: A Spatial Epidemiology Case Study of Soil Pb Contamination

Heavy industrialization has resulted in the contamination of soil by metals from anthropogenic sources in Anniston, Alabama. This situation calls for increased public awareness of the soil contamination issue and better knowledge of the main factors contributing to the potential sources contaminating residential soil. The purpose of this spatial epidemiology research is to describe the effects of physical factors on the concentration of lead (Pb) in soil in Anniston AL, and to determine the socioeconomic and demographic characteristics of those residing in areas with higher soil contamination. Spatial regression models are used to account for spatial dependencies using these explanatory variables. After accounting for covariates and multicollinearity, results of the analysis indicate that lead concentration in soils varies markedly in the vicinity of a specific foundry (Foundry A), and that proximity to railroads explained a significant amount of spatial variation in soil lead concentration. Moreover, elevated soil lead levels were identified as a concern in industrial sites, neighborhoods with a high density of old housing, a high percentage of African American population, and a low percent of occupied housing units. The use of spatial modelling allows for better identification of significant factors that are correlated with soil lead concentrations.

Screening for Elevated Blood Lead Levels in Children: Assessment of Criteria and a Proposal for New Ones in France

The decline in children’s Blood Lead Levels (BLL) raises questions about the ability of current lead poisoning screening criteria to identify those children most exposed. The objectives of the study were to evaluate the performance of current screening criteria in identifying children with blood lead levels higher than 50 µg/L in France, and to propose new criteria. Data from a national French survey, conducted among 3831 children aged 6 months to 6 years in 2008–2009 were used. The sensitivity and specificity of the current criteria in predicting blood lead levels higher than or equal to 50 µg/L were evaluated. Two predictive models of BLL above 44 µg/L (for lack of sufficient sample size at 50 µg/L) were built: the first using current criteria, and the second using newly identified risk factors. For each model, performance was studied by calculating the area under the ROC (Receiver Operating Characteristic) curve. The sensitivity of current criteria for detecting BLL higher than or equal to 50 µg/L was 0.51 (0.26; 0.75) and specificity was 0.66 (0.62; 0.70). The new model included the following criteria: foreign child newly arrived in France, mother born abroad, consumption of tap water in the presence of lead pipes, pre-1949 housing, period of construction of housing unknown, presence of peeling paint, parental smoking at home, occupancy rates for housing and child’s address in a cadastral municipality or census block comprising more than 6% of housing that is potentially unfit and built pre-1949. The area under the ROC curve was 0.86 for the new model, versus 0.76 for the current one. The lead poisoning screening criteria should be updated. The risk of industrial, occupational and hobby-related exposure could not be assessed in this study, but should be kept as screening criteria.

A Review and Framework for Categorizing Current Research and Development in Health Related Geographical Information Systems (GIS) Studies

OBJECTIVES

The application of GIS in health science has increased over the last decade and new innovative application areas have emerged. This study reviews the literature and builds a framework to provide a conceptual overview of the domain, and to promote strategic planning for further research of GIS in health.

METHOD

The framework is based on literature from the library databases Scopus and Web of Science. The articles were identified based on keywords and initially selected for further study based on titles and abstracts. A grounded theory-inspired method was applied to categorize the selected articles in main focus areas. Subsequent frequency analysis was performed on the identified articles in areas of infectious and non-infectious diseases and continent of origin.

RESULTS

A total of 865 articles were included. Four conceptual domains within GIS in health sciences comprise the framework: spatial analysis of disease, spatial analysis of health service planning, public health, health technologies and tools. Frequency analysis by disease status and location show that malaria and schistosomiasis are the most commonly analyzed infectious diseases where cancer and asthma are the most frequently analyzed non-infectious diseases. Across categories, articles from North America predominate, and in the category of spatial analysis of diseases an equal number of studies concern Asia.

CONCLUSION

Spatial analysis of diseases and health service planning are well-established research areas. The development of future technologies and new application areas for GIS and data-gathering technologies such as GPS, smartphones, remote sensing etc. will be nudging the research in GIS and health.

Exploring childhood lead exposure through GIS: a review of the recent literature

Childhood exposure to lead remains a critical health control problem in the US. Integration of Geographic Information Systems (GIS) into childhood lead exposure studies significantly enhanced identifying lead hazards in the environment and determining at risk children. Research indicates that the toxic threshold for lead exposure was updated three times in the last four decades: 60 to 30 micrograms per deciliter (µg/dL) in 1975, 25 µg/dL in 1985, and 10 µb/dL in 1991. These changes revealed the extent of lead poisoning. By 2012 it was evident that no safe blood lead threshold for the adverse effects of lead on children had been identified and the Center for Disease Control (CDC) currently uses a reference value of 5 µg/dL. Review of the recent literature on GIS-based studies suggests that numerous environmental risk factors might be critical for lead exposure. New GIS-based studies are used in surveillance data management, risk analysis, lead exposure visualization, and community intervention strategies where geographically-targeted, specific intervention measures are taken.

Spatial analysis of the home addresses of hospital patients with hepatitis B infection or hepatoma in Shenzhen, China from 2010 to 2012

Background: Hepatoma associated with hepatitis B infection is a major public health problem in Shenzhen (China) and worldwide. China has the largest number of people infected with the hepatitis B virus (HBV), and many studies have demonstrated that HBV infection is associated with hepatoma development. Shenzhen officials have been attempting to monitor and control these diseases for many years. The methodology and the results of this study may be useful in developing a system to monitor, prevent and control these diseases. Methods: The aim of the study was to analyze HBV infection and hepatoma distribution characteristics and patterns in Shenzhen by combining geographic information system (GIS) technology and spatial analysis. The study used data from patients at the district level from the 2010–2012 population censuses. Results: Only one-third of the patients were female, and 70.7% of all cases were 20–50 years of age. There was no global spatial correlation of the distribution of hepatitis B infections and hepatomas; however, there was a local spatial correlation, and certain sub-districts of the Nanshan district had significant agglomeration effects. Based on incidence density and rate maps, we can conclude that the Shenzhen special zone had a higher incidence density and rate of hepatitis B infections and hepatomas compared with the area outside of the Shenzhen special zone during 2010–2012. Conclusions: This study demonstrated substantial geographic variation in the incidence of hepatitis B infection and hepatoma in Shenzhen. The prediction and control of hepatitis B infections and hepatoma development and interventions for these diseases should focus on disadvantaged areas to reduce disparities. GIS and spatial analysis play an important role in public health risk-reduction programs and may become integral components in the epidemiologic description, analysis and risk assessment of hepatitis B and hepatoma.

Using a geographic information system to improve childhood lead-screening efforts

The Idaho Division of Public Health conducted a pilot study to produce a lead-exposure–risk map to help local and state agencies better target childhood lead-screening efforts. Priority lead-screening areas, at the block group level, were created by using county tax assessor data and geographic information system software. A series of maps were produced, indicating childhood lead-screening prevalence in areas in which there was high potential for exposure to lead. These maps could enable development of more systematically targeted and cost-effective childhood lead-screening efforts.

Are children still at risk for lead poisoning?

BACKGROUND

The prevalence of elevated blood lead levels (EBLLs) has decreased nationally, creating challenges in identifying children at risk.

METHODS

In a community known to have lead hazards, we screened children with a field-administered capillary blood lead test and asked parents to complete a questionnaire about lead risk factors.

RESULTS

Of the 77 child-parent pairs screened with a blood lead test and a parental questionnaire, 4 had finger stick blood lead levels of ≥10 µg/dL. Of these, one child had a confirmatory venous blood lead level >10 µg/dL (1.3%; 95% CI = 0.0%-4.7%), which is near the US prevalence but less than the historic prevalence for this region. A median of 2 risk factors for each of the environmental, behavioral, and knowledge/awareness domains were noted.

CONCLUSIONS

Despite a low prevalence of children with EBLL, parental report suggested that approximately 29% of children had lead-based paint in their home environment.

The important health impact of where a child lives: neighborhood characteristics and the burden of lead poisoning

Toxins and other health threats can cause health problems, whether they are present in the child's own home, other neighborhood homes where the child spends time, or common areas such as playgrounds. We assess the impact of where a child lives on the burden of lead poisoning. Statewide lead screening data was obtained from the Rhode Island Department of Health. Block group level indicators of old housing and poverty were obtained from the US Census. Of the 204,746 study children, 35,416 (17.3%) had a blood lead level≥10 μg/dL. The proportion of study children who were lead poisoned in each block group ranged from 0.0 to 48.6%. The proportion of study children with an elevated blood lead level increased from 8% among children living in block groups in the lowest quintile of poverty to 31% for those in the highest quintile for poverty. Old housing also had an important impact on the risk of lead poisoning. The proportion of children with an elevated blood lead level increased from 7% among children living in block groups in the lowest quintile for pre-1950 housing to 27% for those in the highest quintile for pre-1950 housing. The adjusted odds ratio was 1.64 for the highest quintile of poverty and 1.77 for the highest quintile of pre-1950 housing. The findings of this large, statewide study demonstrate the powerful impact of where children live on the risk of lead poisoning. The findings have important implications for understanding the problem of lead poisoning and for planning primary prevention programs.

Comparing household listing techniques in a rural midwestern Vanguard Center of the National Children's Study

The National Children's Study (NCS) is a longitudinal study that will examine the influence of environmental and social factors on the health and development of 100,000 children, following them from before birth until age 21. Proposed participant recruitment methods call for locating and listing all dwelling units (DUs) located within randomly selected segments within the 105 NCS sites. One of seven Vanguard Centers of the NCS includes four rural counties that span approximately 2,500 square miles. The size of this sampling area presents unique geographic challenges. In order to determine the most efficient method for listing DUs within this large area, a study was undertaken to investigate the differences in the percent of DUs identified and the cost of four different approaches. It compared the on-site listing method of physically identifying each DU with three other methods: plat maps, postal listings, and Geographic Information Systems (GIS)/satellite imagery techniques. The on-site method had the strongest kappa (.85) in terms of identifying true DUs. There was a moderate agreement (.59) with the plat map method, fair agreement (.34) with the postal method, and only a slight agreement (.14) with the GIS/satellite imagery method. The plat map, postal listing, and GIS/satellite methods were less time-consuming than the on-site method.

Comparing lead poisoning risk assessment methods: census block group characteristics vs. zip codes as predictors

OBJECTIVE

We determined which children should be tested for elevated blood lead levels (BLLs) in the face of financial and practical barriers to universal screening efforts and within 2009 Centers for Disease Control and Prevention recommendations allowing health departments to develop BLL screening strategies.

METHODS

We used the Michigan database of BLL tests from 1998 through 2005, which contains address, Medicaid eligibility, and race data. Linking addresses to U.S. Census 2000 data by block group provided neighborhood sociodemographic and housing characteristics. To derive an equation predicting BLL, we treated BLL as a continuous variable and used Hierarchical Linear Modeling to estimate the prediction equation.

RESULTS

Census block groups explained more variance in BLL than tracts and much more than dichotomized zip code risk (which is current pediatric practice). Housing built before 1940, socioeconomic status and racial/ethnic characteristics of the block group, child characteristics, and empirical Bayesian residuals explained more than 41% of the variance in BLL during 1998-2001. By contrast, zip code risk and Medicaid status only explained 15% of the BLL variance. An equation using 1998-2001 BLL data predicted well for BLL tests performed in 2002-2005. While those who received BLL tests had above-average risk, this method produced minimal bias in using the prediction equation for all children.

CONCLUSIONS

Our equation offers better specificity and sensitivity than using dichotomized zip codes and Medicaid status, thereby identifying more high-risk children while also offering substantial cost savings. Our prediction equation can be used with a simple Internet-based program that allows health-care providers to enter minimal information and determine whether a BLL test is recommended.

Applying Dixon and Dixon's Integrative Model for Environmental Health Research toward a critical analysis of childhood lead poisoning in Canada

Occurrences of childhood lead poisoning resulting from exposure to residential sources of lead is an underresearched area in Canada. Dixon and Dixon's Integrative Model for Environmental Health Research substantiates this claim by grouping Canadian research on this health topic into the model's 4 domains: physiological, vulnerability, epistemological, and health protection. This process is useful not only for identifying research gaps within the Canadian context but also in setting the groundwork for a future critical analysis to illuminate the sociopolitical and economic influences that shape healthcare knowledge, and ultimately, influence how healthcare providers and policy makers produce and use this information.

Screening for lead poisoning: a geospatial approach to determine testing of children in at-risk neighborhoods

OBJECTIVE

To develop a spatial strategy to assess neighborhood risk for lead exposure and neighborhood-level blood lead testing of young children living in the city of Atlanta, Georgia.

STUDY DESIGN

This ecologic study used existing blood lead results of children aged <or=36 months tested and living in one of Atlanta's 236 neighborhoods in 2005. Geographic information systems used Census, land parcel, and neighborhood spatial data to create a neighborhood priority testing index on the basis of proxies for poverty (Special Supplemental Nutrition Program for Women, Infants and Children [WIC] enrollment) and lead in house paint (year housing built).

RESULTS

In 2005, only 11.9% of Atlanta's 18,627 children aged <or=36 months living in the city had blood lead tests, despite a high prevalence of risk factors: 75,286 (89.6%) residential properties were built before 1978, and 44% of children were enrolled in WIC. Linear regression analysis indicated testing was significantly associated with WIC status (P < .001) but not with old housing.

CONCLUSIONS

This neighborhood spatial approach provided smaller geographic areas to assign risk and assess testing in a city that has a high prevalence of risk factors for lead exposure. Testing may be improved by collaboration between pediatricians and public health practitioners.

A framework for widespread replication of a highly spatially resolved childhood lead exposure risk model

BACKGROUND

Preventive approaches to childhood lead poisoning are critical for addressing this longstanding environmental health concern. Moreover, increasing evidence of cognitive effects of blood lead levels < 10 microg/dL highlights the need for improved exposure prevention interventions.

OBJECTIVES

Geographic information system-based childhood lead exposure risk models, especially if executed at highly resolved spatial scales, can help identify children most at risk of lead exposure, as well as prioritize and direct housing and health-protective intervention programs. However, developing highly resolved spatial data requires labor-and time-intensive geocoding and analytical processes. In this study we evaluated the benefit of increased effort spent geocoding in terms of improved performance of lead exposure risk models.

METHODS

We constructed three childhood lead exposure risk models based on established methods but using different levels of geocoded data from blood lead surveillance, county tax assessors, and the 2000 U.S. Census for 18 counties in North Carolina. We used the results to predict lead exposure risk levels mapped at the individual tax parcel unit.

RESULTS

The models performed well enough to identify high-risk areas for targeted intervention, even with a relatively low level of effort on geocoding.

CONCLUSIONS

This study demonstrates the feasibility of widespread replication of highly spatially resolved childhood lead exposure risk models. The models guide resource-constrained local health and housing departments and community-based organizations on how best to expend their efforts in preventing and mitigating lead exposure risk in their communities.

Geomatics in injury prevention: the science, the potential and the limitations

BACKGROUND

Geomatics describes the activities involved in acquiring and managing geographical data and producing geographical information for scientific, administrative and technical endeavors. As an emerging science, geomatics has a great potential to support public health. Geomatics provides a conceptual foundation for the development of geographic information systems (GIS), computerized tools that manage and display geographical data for analytical applications. As descriptive epidemiology typically involves the examination of person, place and time in the occurrence of disease or injury, geomatics and GIS can play an important role in understanding and preventing injury.

AIM

This article provides a background to geomatics for those in the injury prevention field who are unfamiliar with spatial analysis. We hope to stimulate researchers and practitioners to begin to use geomatics to assist in the prevention of injury.

METHODS

The authors illustrate the potential benefits and limitations of geomatics in injury prevention in a non-technical way through the use of maps and analysis.

RESULTS

By analysing the location of patients treated for fall injuries in Central Toronto using GIS, some demographic and land use variables, such as household income, age, and the location of homeless shelters, were identified as explanatory factors for the spatial distribution.

CONCLUSION

By supporting novel approaches to injury prevention, geomatics has a great potential for efforts to combat the burden of injury. Despite some limitations, those with an interest in injury prevention could benefit from this science.

Changes in blood lead levels associated with use of chloramines in water treatment systems

BACKGROUND

More municipal water treatment plants are using chloramines as a disinfectant in order to reduce carcinogenic by-products. In some instances, this has coincided with an increase in lead levels in drinking water in those systems. Lead in drinking water can be a significant health risk.

OBJECTIVES

We sought to test the potential effect of switching to chloramines for disinfection in water treatment systems on childhood blood lead levels using data from Wayne County, located in the central Coastal Plain of North Carolina.

METHODS

We constructed a unified geographic information system (GIS) that links blood lead screening data with age of housing, drinking water source, and census data for 7,270 records. The data were analyzed using both exploratory methods and more formal multivariate techniques.

RESULTS

The analysis indicates that the change to chloramine disinfection may lead to an increase in blood lead levels, the impact of which is progressively mitigated in newer housing.

CONCLUSIONS

Introducing chloramines to reduce carcinogenic by-products may increase exposure to lead in drinking water. Our research provides guidance on adjustments in the local childhood lead poisoning prevention program that should accompany changes in water treatment. As similar research is conducted in other areas, and the underlying environmental chemistry is clarified, water treatment strategies can be optimized across the multiple objectives that municipalities face in providing high quality drinking water to local residents.

Geographic information systems: a new tool for environmental health assessments

OBJECTIVES

(1) To develop tools for health care professionals and communities to assess environmental exposures and (2) to evaluate the utility of integrating patient-reported environmental health information with geographic information systems (GIS) mapping of environmental data in a pilot study.

METHODS

A survey was used to collect self-reported environmental exposure and health data from a convenience sample of people at an urban community health center (N=101). Environmental exposure and census information were obtained from federal agencies. Analysis was performed using descriptive statistics and GIS.

RESULTS

Frequent environmental health risk factors were reported, such as older housing (93%) and household smoking (78%). Health problems including asthma (54%) and lead poisoning (14%) were reported. Odds ratios indicated a statistically significant relationship between mold/mildew and reporting asthma. GIS was found to be a useful tool in displaying environmental risk factors and potentially associated health effects.

CONCLUSIONS

Given the important role that environmental health risks can play in public health, it is critical that community/public health nurses begin to integrate environmental health assessment skills into their professional practices. Simple community surveys can be an effective means to raise awareness about environmental health risk factors and utilizing GIS can further enhance the accessibility of the combined exposure and health information.

A federal agency's role in fulfilling the public health core functions: the childhood lead poisoning prevention program model

The Institute of Medicine identified 3 core functions of public health: assessment, policy development, and assurance. Federal, state, and local public health agencies all have an obligation to provide these vital functions to ensure conditions in which people can be healthy. However, the few publications that provide core function applications only focus on applications at the local or state levels. The Centers for Disease Control and Prevention's Childhood Lead Poisoning Prevention Program uses a comprehensive public health approach. This article describes the Centers for Disease Control and Prevention's leading role in applying the core public health functions to prevent childhood lead poisoning.

High-intensity targeted screening for elevated blood lead levels among children in 2 inner-city Chicago communities

OBJECTIVES

We assessed the prevalence of elevated blood lead levels (> or = 10 micrograms of lead per deciliter of blood), risk factors, and previous blood lead testing among children in 2 high-risk Chicago, Ill, communities.

METHODS

Through high-intensity targeted screening, blood lead levels were tested and risks were assessed among a representative sample of children aged 1 to 5 years who were at risk for lead exposure.

RESULTS

Of the 539 children who were tested, 27% had elevated blood lead levels, and 61% had never been tested previously. Elevated blood lead levels were associated with chipped exterior house paint.

CONCLUSIONS

Most of the children who lived in these communities--where the prevalence for elevated blood lead levels among children was 12 times higher than the national prevalence--were not tested for lead poisoning. Our findings highlight the need for targeted community outreach that includes testing blood lead levels in accordance with the American Academy of Pediatrics' recommendations.

Should the Centers for Disease Control and Prevention's childhood lead poisoning intervention level be lowered?

The US Centers for Disease Control and Prevention (CDC) in 1991 chose 10 micro g/dL as an initial screening level for lead in children's blood. Current data on health risks and intervention options do not support generally lowering that level, but federal lead poisoning prevention efforts can be improved by revising the follow-up testing schedule for infants aged 1 year or less with blood lead levels of 5 micro g/dL or higher; universal education about lead exposure risks; universal administration of improved, locally validated risk-screening questionnaires; enhanced compliance with targeted screening recommendations and federal health program requirements; and development by regulatory agencies of primary prevention criteria that do not use the CDC's intervention level as a target "safe" lead exposure.

Environmental measures of physical activity supports: perception versus reality

BACKGROUND

Perceptions of the environment and physical activity have been associated using survey methods, yet little is known about the validity of environmental surveys. In this study, perceptions of the environment at neighborhood and community levels were assessed (1) to determine validity by comparing respondent perceptions to objective measures and (2) to determine test-retest reliability of the survey.

METHODS

A telephone survey was administered to a stratified sample of Sumter County, South Carolina adults. Respondents' home addresses were mapped using a geographic information system (GIS) (n =1112). As an indicator of validity, kappa statistics were used to measure agreement between perceptions and objective measures identified at neighborhood and community levels using GIS. A second survey in an independent sample (n=408) assessed test-retest reliability.

RESULTS

When assessing perceptions of environmental and physical activity in a defined geographic area, validity and reliability for neighborhood survey items were kappa= -0.02 to 0.37 and rho=0.42 to 0.74, and for community survey items were kappa= -0.07 to 0.25 and rho=0.28 to 0.56.

CONCLUSIONS

Although causality between perception of access and safety and actual physical activity level cannot be assumed, those meeting national physical activity guidelines or reporting some physical activity demonstrated greatest agreement with access to recreation facilities, while those not meeting the guidelines demonstrated greater agreement with safety of recreation facilities. Factors such as distance and behavior may explain differences in perceptions at neighborhood and community levels. Using local environments with short distances in survey methods improves validity and reliability of results.

Choosing area based socioeconomic measures to monitor social inequalities in low birth weight and childhood lead poisoning: The Public Health Disparities Geocoding Project (US)

STUDY OBJECTIVES

: To determine which area based socioeconomic measures can meaningfully be used, at which level of geography, to monitor socioeconomic inequalities in childhood health in the US.

DESIGN

Cross sectional analysis of birth certificate and childhood lead poisoning registry data, geocoded and linked to diverse area based socioeconomic measures that were generated at three geographical levels: census tract, block group, and ZIP code.

SETTING

Two US states: Massachusetts (1990 population=6,016,425) and Rhode Island (1990 population=1,003,464).

PARTICIPANTS

All births born to mothers ages 15 to 55 years old who were residents of either Massachusetts (1989-1991; n=267,311) or Rhode Island (1987-1993; n=96 138), and all children ages 1 to 5 years residing in Rhode Island who were screened for lead levels between 1994 and 1996 (n=62,514 children, restricted to first test during the study period).

MAIN RESULTS

Analyses of both the birth weight and lead data indicated that: (a) block group and tract socioeconomic measures performed similarly within and across both states, while ZIP code level measures tended to detect smaller effects; (b) measures pertaining to economic poverty detected stronger gradients than measures of education, occupation, and wealth; (c) results were similar for categories generated by quintiles and by a priori categorical cut off points; and (d) the area based socioeconomic measures yielded estimates of effect equal to or augmenting those detected, respectively, by individual level educational data for birth outcomes and by the area based housing measure recommended by the US government for monitoring childhood lead poisoning.

CONCLUSIONS

Census tract or block group area based socioeconomic measures of economic deprivation could be meaningfully used in conjunction with US public health surveillance systems to enable or enhance monitoring of social inequalities in health in the United States.

Regional variation in the incidence of symptomatic pesticide exposures: applications of geographic information systems

OBJECTIVE

To evaluate the epidemiology of symptomatic human pesticide exposures using poison control center data and geographic information systems.

METHODS

All symptomatic human pesticide exposures reported to the poison center during the period from January 1 to December 31, 2000 were included for analysis using geographic information systems. A space-time scan statistic was utilized to evaluate for clustering of symptomatic human exposures.

RESULTS

Of 322 symptomatic pesticide exposures, 297 (92%) contained spatial identifiers that could be further analyzed using geographic information systems. A spatial and temporal cluster of symptomatic pesticide exposures was identified during the periodfrom April 1 to August 31, 2000, covering a large geographic area of eastern and predominantly rural regions of the state. The relative risk of reporting a symptomatic pesticide exposure among individuals living within this geographic area was 1.8 (log likelihood ratio = 18.5, P = 0.0005).

CONCLUSIONS

Geographic information systems can be effectively utilized by poison control centers to study regional and temporal variation in the incidence of human pesticide exposures. With the collection of more specific spatial identifiers, geographic information systems may have many additional applications in the surveillance and prevention of pesticide and other sentinel event exposures.

Mapping for prevention: GIS models for directing childhood lead poisoning prevention programs

Environmental threats to children's health--especially low-level lead exposure--are complex and multifaceted; consequently, mitigation of these threats has proven costly and insufficient and has produced economic and racial disparities in exposure among populations. Policy makers, public health officials, child advocates, and others currently lack the appropriate infrastructure to evaluate children's risk and exposure potential across a broad range of risks. Unable to identify where the highest risk of exposure occurs, children's environmental health programs remain mitigative instead of preventive. In this article we use geographic information system spatial analysis of data from blood lead screening, county tax assessors, and the U.S. Census to predict statistically based lead exposure risk levels mapped at the individual tax parcel unit in six counties in North Carolina. The resulting model uses weighted risk factors to spatially locate modeled exposure zones, thus highlighting critical areas for targeted intervention. The methods presented here hold promise for application and extension to the other 94 North Carolina counties and nationally, as well as to other environmental health risks.