The association between state housing policy and lead poisoning in children

Neurotoxicants, Micronutrients, and Social Environments

SUMMARY—Systematic research evaluating the separate and interacting impacts of neurotoxicants, micronutrients, and social environments on children's cognition and behavior has only recently been initiated. Years of extensive human epidemiologic and animal experimental research document the deleterious impact of lead and other metals on the nervous system. However, discrepancies among human studies and between animal and human studies underscore the importance of variations in child nutrition as well as social and behavioral aspects of children's environments that mitigate or exacerbate the effects of neurotoxicants.

In this monograph, we review existing research on the impact of neurotoxic metals, nutrients, and social environments and interactions across the three domains. We examine the literature on lead, mercury, manganese, and cadmium in terms of dispersal, epidemiology, experimental animal studies, effects of social environments, and effects of nutrition.

Research documenting the negative impact of lead on cognition and behavior influenced reductions by the Center for Disease Control in child lead-screening guidelines from 30 micrograms per deciliter (μg/dL) in 1975 to 25 μg/dL in 1985 and to 10 μg/dL in 1991. A further reduction is currently being considered. Experimental animal research documents lead's alteration of glutamate-neurotransmitter (particularly N-methyl-D-aspartate) activity vital to learning and memory. In addition, lead induces changes in cholinergic and dopaminergic activity. Elevated lead concentrations in the blood are more common among children living in poverty and there is some evidence that socioeconomic status influences associations between lead and child outcomes. Micronutrients that influence the effects of lead include iron and zinc.

Research documenting the negative impact of mercury on children (as well as adults) has resulted in a reference dose (RfD) of 0.1 microgram per kilogram of body weight per day (μg/kg/day). In animal studies, mercury interferes with glutamatergic, cholinergic, and dopaminergic activity. Although evidence for interactions of mercury with children's social contexts is minimal, researchers are examining interactions of mercury with several nutrients.

Research on the effects of cadmium and manganese on child cognition and behavior is just beginning. Experimental animal research links cadmium to learning deficits, manganese to behaviors characteristic of Parkinson's disease, and both to altered dopaminergic functioning.

We close our review with a discussion of policy implications, and we recommend interdisciplinary research that will enable us to bridge gaps within and across domains.

Geographic region of residence and blood lead levels in US children: results of the National Health and Nutrition Examination Survey

PURPOSE

This study investigated the association between geographic region and blood lead levels (BLLs) in US children, as well as trends in this relationship, using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

SAS® and SUDAAN® software programs were utilized to develop linear regression models adjusted for several factors associated with BLLs.

RESULTS

The largest decline in BLLs was observed in Northeastern children, while the percentage of children with elevated blood lead levels decreased the most for the West and Northeast. Lead levels of Northeastern children were still higher than those of children living in the West. However, levels were not different among children residing in the Northeast, Midwest, and South, and the blood lead concentrations were less than 5 μg/dL for all but one subgroup of children and less than 2 μg/dL for >70% of the subgroups. More importantly, the effects of different risk factors for higher blood lead levels varied by region even after adjusting for all other covariates.

CONCLUSIONS

The results of this study not only provide relevant and current blood lead levels for US children that can be used as reference values to evaluate biomonitoring data, but can also be used to help direct prevention and surveillance strategies to reduce lead in the environment of at-risk children.

Case management protocol and declining blood lead concentrations among children

INTRODUCTION

Blood lead concentrations among children aged 6 years and younger become a concern at 10 microg/dL (0.48 micromol/L) or higher. The authors' objective was to determine whether initial blood lead concentrations of 10-19 microg/dL (0.48-0.96 micromol/L) declined among children aged 3 years and younger and whether the magnitude of decline was associated with the case management protocol of the state or local childhood lead poisoning prevention program.

METHODS

The authors analyzed childhood blood lead surveillance data from 1994 through 1995 and case management protocols from six states that reported the results of all blood lead tests. The study included 2109 children aged 2 years or younger who had a venous blood lead concentration of 10-19 microg/dL (0.48-0.96 micromol/L) and a follow-up venous blood lead test within 3 to 12 months.

RESULTS

Overall, blood lead concentrations increased by 0.25 microg/dL (0.01 micromol/L) between the time of the initial elevated blood lead test and the follow-up test, but concentrations declined by 1.96 microg/dL (0.09 micromol/L) among children covered by a case management protocol that included a home visit and by 0.92 microg/dL (0.04 micromol/L) among those covered by a protocol that included a lead source investigation. The decline remained significant after we adjusted for the child's age.

CONCLUSION

These findings suggest that childhood lead prevention programs should consider focusing their efforts on home visits and lead source investigations.

Environmental mercury release, special education rates, and autism disorder: an ecological study of Texas

The association between environmentally released mercury, special education and autism rates in Texas was investigated using data from the Texas Education Department and the United States Environmental Protection Agency. A Poisson regression analysis adjusted for school district population size, economic and demographic factors was used. There was a significant increase in the rates of special education students and autism rates associated with increases in environmentally released mercury. On average, for each 1,000 lb of environmentally released mercury, there was a 43% increase in the rate of special education services and a 61% increase in the rate of autism. The association between environmentally released mercury and special education rates were fully mediated by increased autism rates. This ecological study suggests the need for further research regarding the association between environmentally released mercury and developmental disorders such as autism. These results have implications for policy planning and cost analysis.

Geographic analysis of blood lead levels in New York State children born 1994-1997

We examined the geographic distribution of the blood lead levels (BLLs) of 677,112 children born between 1994 and 1997 in New York State and screened before 2 years of age. Five percent of the children screened had BLLs higher than the current Centers for Disease Control and Prevention action level of 10 microg/dL. Rates were higher in upstate cities than in the New York City area. We modeled the relationship between BLLs and housing and socioeconomic characteristics at the ZIP code level. Older housing stock, a lower proportion of high school graduates, and a higher percentage of births to African-American mothers were the community characteristics most associated with elevated BLLs. Although the prevalence of children with elevated BLLs declined 44% between those born in 1994 and those born in 1997, the rate of improvement may be slowing down. Lead remains an environmental health problem in inner-city neighborhoods, particularly in upstate New York. We identified areas having a high prevalence of children with elevated BLLs. These communities can be targeted for educational and remediation programs. The model locates areas with a higher or lower prevalence of elevated BLLs than expected. These communities can be studied further at the individual level to better characterize the factors that contribute to these differences.

The effects of housing interventions on child health

Housing hazards contribute to considerable morbidity and mortality among millions of children each year in the US, but few interventions are proven to control asthma and lead poisoning. Moreover, there is little evidence that many of the current recommendations to control residential hazards are safe and efficacious. The only interventions that have been found to work consistently are home visitation programs and home modification, such as installment of window guards and carpet removal. Altering the environment to protect the health of children requires pediatrician intervention. New models of cooperation between pediatricians and public health agencies must deal with residential hazards in an integrated manner and cannot be focused on one disease process or one method at a time. With research in more effective environmental interventions and pediatric-public-health partnerships, primary and secondary prevention of diseases from residential hazards may become a reality in the future.

Housing standards: a glossary of housing and health

This glossary has been designed to provide definitions that take account of different disciplinary and policy traditions and to consider the aspects of housing that provide scope for possible concerted research and action.

The built environment and its relationship to the public's health: the legal framework

The built environment significantly affects the public's health. This was most obvious when infectious disease was the primary public health threat during the industrial revolution; unsanitary conditions and overcrowded urban areas facilitated the spread of infection. However, even today in the age of chronic diseases there remains an important connection between population health and the built environment. Physical spaces can expose people to toxins or pollutants and influence lifestyles that contribute to diabetes, coronary vascular disease, and asthma. Public health advocates can help shape the design of cities and suburbs in ways that improve public health, but to do so effectively they need to understand the legal framework. This article reviews the connection between public health and the built environment and then describes the legal pathways for improving the design of our built environment.

Is the U.S. Environmental Protection Agency brownfields assessment pilot program environmentally just?

In the early 1990s, the U.S. Environmental Protection Agency (U.S. EPA) started a grant program to assist communities redevelop brownfields, which are abandoned or underutilized sites that have real or perceived contamination. In addition to determining if the communities receiving the grants were the most distressed cities in the United States, we also evaluate the U.S. EPA program in terms of environmental justice at the macro scale. Using 1990 U.S. Census of Housing and Population data and a matched-cities methodology, we compared the brownfields pilot cities to other communities in the United States. We found that regardless of intent, the U.S. EPA program is environmentally just by disproportionately awarding grants to the most economically distressed cities. We also found that the cities that received funding in the early years of the program were more economically distressed than cities receiving the funding more recently.

A UML-based meta-framework for system design in public health informatics

The National Agenda for Public Health Informatics calls for standards in data and knowledge representation within public health, which requires a multi-level framework that links all aspects of public health.

METHOD

The literature of public health informatics and public health informatics application were reviewed. A UML-based systems analysis was performed. Face validity of results was evaluated in analyzing the public health domain of lead poisoning.

RESULTS

The core class of the UML-based system of public health is the Public Health Domain, which is associated with multiple Problems, for which Actors provide Perspectives. Actors take Actions that define, generate, utilize and/or evaluate Data Sources. The life cycle of the domain is a sequence of activities attributed to its problems that spirals through multiple iterations and realizations within a domain.

CONCLUSION

The proposed Public Health Informatics Meta-Framework broadens efforts in applying informatics principles to the field of public health

The effect of interior lead hazard controls on children's blood lead concentrations: a systematic evaluation

Dust control is often recommended to prevent children's exposure to residential lead hazards, but the effect of these controls on children's blood lead concentrations is uncertain. We conducted a systematic review of randomized, controlled trials of low-cost, lead hazard control interventions to determine the effect of lead hazard control on children's blood lead concentration. Four trials met the inclusion criteria. We examined mean blood lead concentration and elevated blood lead concentrations (> or = 10 microg/dL, > or = 15 microg/dL, and > or = 20 microg/dL) and found no significant differences in mean change in blood lead concentration for children by random group assignment (children assigned to the intervention group compared with those assigned to the control group). We found no significant difference between the intervention and control groups in the percentage of children with blood lead > or = 10 microg/dL, 29% versus 32% [odds ratio (OR), 0.85; 95% confidence interval (CI), 0.56-1.3], but there was a significant difference in the percentage of children with blood lead > or = 15 microg/dL between the intervention and control groups, 6% versus 14% (OR, 0.40; 95% CI, 0.21-0.80) and in the percentage of children with blood lead > or = 20 microg/dL between the intervention and control groups, 2% versus 6% (OR, 0.29; 95% CI, 0.10-0.85). We conclude that although low-cost, interior lead hazard control was associated with 50% or greater reduction in the proportion of children who had blood lead concentrations exceeding 15 microg/dL and > or = 20 microg/dL, there was no substantial effect on mean blood lead concentration.

The effectiveness of housing policies in reducing children's lead exposure

OBJECTIVES

This study evaluated the relation of housing policies to risk of subsequent lead exposure in addresses where lead-poisoned children had lived.

METHODS

Addresses where children with lead poisoning lived between May 1992 and April 1993 were selected from lead screening registries in 2 northeastern states differing in their enforcement of lead poisoning prevention statutes. Blood lead levels of subsequently resident children, exterior condition, tax value, age, and census tract characteristics were collected. The odds of elevated blood lead levels in subsequently resident children were calculated with logistic regression.

RESULTS

The risk of identifying 1 or more children with blood lead levels of 10 micrograms/dL or greater was 4 times higher in addresses with limited enforcement. Controlling for major confounders had little effect on the estimate.

CONCLUSIONS

Enforcement of housing policies interrupts the cycle of repeated lead exposure.

Prevention of childhood lead poisoning

Although past national public health efforts have reduced lead exposure significantly, lead poisoning remains the most common environmental health problem affecting American children. Currently, lead exposure occurs predominantly through ingestion of lead-contaminated household dust and soil in older housing containing lead-based paint; exposure can be increased with housing deterioration or renovation. Environmental prevention efforts focus on improvement in risk assessment, development of housing-based standards for lead-based paint hazards, and safe and cost-effective lead hazard remediation techniques. Educational efforts address parental awareness of lead exposure pathways, hygiene, and housekeeping measures to prevent ingestion of dust and soil. Blood lead screening is recommended either universally at ages 1 and 2 years or in a targeted manner where local health departments can document a low prevalence of elevated blood lead levels. Nutritional interventions involve provision of regular meals containing adequate amounts of calcium and iron and supplementation for iron deficiency. Lead chelation should complement environmental, nutritional, and educational interventions, when indicated. Collaboration of multiple federal agencies in a new strategy to eliminate childhood lead poisoning should further prevention efforts.