Primary prevention of childhood lead exposure: A randomized trial of dust control

Knowledge, confidence, and reported behaviors that promote safe water drinking among women of reproductive age

Introduction

Drinking lead contaminated water during pregnancy is associated with infant mortality. All women of reproductive age are advised by health agencies to adhere to healthy behaviors due to the chance of unintended pregnancy. Our objectives are to understand knowledge, confidence, and reported behaviors that promote safe water drinking and prevent lead exposure among women of reproductive age.

Methods

A survey among females of reproductive age from the University of Michigan - Flint was administered. A total of 83 females who wished to become pregnant one day participated.

Results

Low levels of knowledge, confidence, and reported preventative health behaviors related to safe water drinking and lead exposure prevention existed. Specifically, 71.1% of respondents (59 of 83) were not at all or were somewhat confident in their ability to choose an appropriate lead water filter. Most participants rated their knowledge on how to decrease exposure to lead during pregnancy as poor/fair. No statistically significant differences were detected between respondents residing inside and outside of the city of Flint, Michigan for most variables assessed.

Conclusion

While the small sample size is a limitation, the study adds to an area of scarce research. Despite widespread media attention and resources directed toward reducing the negative health effects of lead exposure following the Flint Water Crisis, significant gaps in knowledge related to safe water drinking remain. Interventions are needed to increase knowledge, confidence, and healthy behaviors that promote safe water drinking among women of reproductive age.

Factors affecting lead dust in construction workers' homes in the Greater Boston Area

Lead is a known reproductive, developmental, and neurological toxicant. Workers with a high likelihood of being exposed to lead at work may inadvertently transport lead home from work, known as "take-home exposure." This is concerning for many workers for whom a workplace intervention is not feasible because their worksites and employers often change, rendering centralized strategies insufficient. This study aimed to better understand the connection between lead in the home of workers living with children and work in construction (n = 23), while other occupations were used as a comparison group (janitorial n = 5, autobody n = 2). Thirty workers living in disadvantaged communities in the Greater Boston area were recruited in 2018-2019 through collaboration with non-profits and worker unions with expertise working with low-income or immigrant workers. Construction workers that performed renovations, bridge constructions, welding, metal work, and demolitions were prioritized during recruitment. During a visit to their residences, a worker questionnaire was administered, and observations and a dust vacuumed sample of the home were collected. Factors predicting lead in home dust were explored by a bivariate analysis and a multivariable regression model. We found lead in homes' dust in the range of 20-8,310 ppm. Homes of construction workers generally had higher and more variable lead dust concentrations (mean 775, max 8,300 ppm) than autobody and janitor worker homes combined (mean 296, max 579 ppm). Five of the construction workers' home lead dust concentrations exceeded US guidelines for yard soil in children's play areas of 400 ppm, and were similar to other studies of homes near lead smelters, superfund sites, or in the Boston area in the early 1990s, pointing to disparities relating to work. Results from the multivariable regression model suggest that lead dust in homes of workers was associated with sociodemographic-, home-, and work-related factors, and pointed to overlapping vulnerabilities; however, a larger sample size is needed to verify findings. Results provide evidence that work-related factors are important to consider when assessing home exposures, and that take-home exposures for workers in lead high-risk jobs such as construction may be an important source of exposure in the home prime for public health intervention at work, home, and community levels.

Early life blood lead levels and asthma diagnosis at age 4-6 years

The USA has a high burden of childhood asthma. Previous studies have observed associations between higher blood lead levels and greater hypersensitivity in children. The objective of the present study was to estimate the association between blood lead concentrations during early childhood and an asthma diagnosis between 48 and 72 months of age amongst a cohort with well-characterized blood lead concentrations. Blood lead concentrations were measured at 6, 12, 18, 24, 36, and 48 months of age in 222 children. The presence of an asthma diagnosis between 48 and 72 months was assessed using a questionnaire which asked parents or guardians whether they had been told by a physician, in the past 12 months, that their child had asthma. Crude and adjusted risk ratios (RR) of an asthma diagnosis were estimated for several parameterizations of blood lead exposure including lifetime average (6 to 48 months) and infancy average (6 to 24 months) concentrations. After adjustment for child sex, birthweight, daycare attendance, maternal race, education, parity, breastfeeding, income, and household smoking, age-specific or composite measures of blood lead were not associated with asthma diagnosis by 72 months of age in this cohort.

Household interventions for secondary prevention of domestic lead exposure in children

BACKGROUND

Lead exposure is a serious health hazard, especially for children. It is associated with physical, cognitive and neurobehavioural impairment in children. There are many potential sources of lead in the environment, therefore trials have tested many household interventions to prevent or reduce lead exposure. This is an update of a previously published review.

OBJECTIVES

To assess the effects of household interventions intended to prevent or reduce further lead exposure in children on improvements in cognitive and neurobehavioural development, reductions in blood lead levels and reductions in household dust lead levels.

SEARCH METHODS

In March 2020, we updated our searches of CENTRAL, MEDLINE, Embase, 10 other databases and ClinicalTrials.gov. We also searched Google Scholar, checked the reference lists of relevant studies and contacted experts to identify unpublished studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of household educational or environmental interventions, or combinations of interventions to prevent lead exposure in children (from birth to 18 years of age), where investigators reported at least one standardised outcome measure.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 17 studies (three new to this update), involving 3282 children: 16 RCTs (involving 3204 children) and one quasi-RCT (involving 78 children). Children in all studies were under six years of age. Fifteen studies took place in urban areas of North America, one in Australia and one in China. Most studies were in areas with low socioeconomic status. Girls and boys were equally represented in those studies reporting this information. The duration of the intervention ranged from three months to 24 months in 15 studies, while two studies performed interventions on a single occasion. Follow-up periods ranged from three months to eight years. Three RCTs were at low risk of bias in all assessed domains. The other 14 studies were at unclear or high risk of bias; for example, we considered two RCTs and one quasi-RCT at high risk of selection bias and six RCTs at high risk of attrition bias. National or international research grants or governments funded 15 studies, while the other two did not report their funding sources. Education interventions versus no intervention None of the included studies in this comparison assessed effects on cognitive or neurobehavioural outcomes, or adverse events. All studies reported data on blood lead level outcomes. Educational interventions showed there was probably no evidence of a difference in reducing blood lead levels (continuous: mean difference (MD) -0.03, 95% confidence interval (CI) -0.13 to 0.07; I² = 0%; 5 studies, 815 participants; moderate-certainty evidence; log-transformed data), or in reducing floor dust levels (MD -0.07, 95% CI -0.37 to 0.24; I² = 0%; 2 studies, 318 participants; moderate-certainty evidence). Environmental interventions versus no intervention Dust control: one study in this comparison reported data on cognitive and neurobehavioural outcomes, and on adverse events in children. The study showed numerically there may be better neurobehavioural outcomes in children of the intervention group. However, differences were small and the CI included both a beneficial and non-beneficial effect of the environmental intervention (e.g. mental development (Bayley Scales of Infant Development-II): MD 0.1, 95% CI -2.1 to 2.4; 1 study, 302 participants; low-certainty evidence). The same study did not observe any adverse events related to the intervention during the eight-year follow-up, but observed two children with adverse events in the control group (1 study, 355 participants; very low-certainty evidence). Meta-analysis also found no evidence of effectiveness on blood lead levels (continuous: MD -0.02, 95% CI -0.09 to 0.06; I² = 0%; 4 studies, 565 participants; moderate-certainty evidence; log-transformed data). We could not pool the data regarding floor dust levels, but studies reported that there may be no evidence of a difference between the groups (very low-certainty evidence). Soil abatement: the two studies assessing this environmental intervention only reported on the outcome of 'blood lead level'. One study showed a small effect on blood lead level reduction, while the other study showed no effect. Therefore, we deem the current evidence insufficient to draw conclusions about the effectiveness of soil abatement (very low-certainty evidence). Combination of educational and environmental interventions versus standard education Studies in this comparison only reported on blood lead levels and dust lead levels. We could not pool the studies in a meta-analysis due to substantial differences between the studies. Since the studies reported inconsistent results, the evidence is currently insufficient to clarify whether a combination of interventions reduces blood lead levels and floor dust levels (very low-certainty evidence).

AUTHORS' CONCLUSIONS

Based on available evidence, household educational interventions and environmental interventions (namely dust control measures) show no evidence of a difference in reducing blood lead levels in children as a population health measure. The evidence of the effects of environmental interventions on cognitive and neurobehavioural outcomes and adverse events is uncertain too. Further trials are required to establish the most effective intervention for reducing or even preventing further lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in low- and middle-income countries and in differing socioeconomic groups in high-income countries.

Housing and Healthy Child Development: Known and Potential Impacts of Interventions

Housing is often described as an important determinant of health, but less commonly of child health. Despite acknowledgment of the importance of housing to health, however, there are relatively few studies of the effects of housing interventions on health, and again even fewer on child health. This article argues that a broad focus on healthy child development-as opposed to just physical health-coupled with a conceptual framework outlining specific attributes of housing with the potential to influence child health, should be adopted to guide a comprehensive approach to public health policy for healthy child development. Most housing interventions address direct pathways linking in-home hazard exposures to child health outcomes, with promising but mixed results. But few housing interventions address the broader aspects of healthy child development. This review addresses potential housing interventions that could impact the broader determinants of healthy child development and accompanying methodological challenges.

Dietary zinc, calcium and nickel are associated with lower childhood blood lead levels

The potential mitigation of elevated blood lead (PbB) levels with nutrient intake remains debatable. A comprehensive review by Kordas (2017) concluded that careful examination of the links between nutrition (nutritional status, nutrients, diet) and lead (Pb) exposure revealed limited and tenuous evidence. We have measured 20 elements including calcium (Ca), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), nickel (Ni), zinc (Zn), and Pb from 6-day duplicate diets of 108 young children over a 5-year period and expressed these as intakes per body weight. Bivariate analyses showed a weak positive association between the Pb content in the diets of the participants and the level of Pb in their blood, as might be expected. Weak, but negative, associations occurred between the other elements in the diet and PbB. The associations for Ca, Mg, Ni and Zn were statistically significant for both subject-based (between subjects) and within-subject effects: that is, as the levels of elements in diet increased, the PbB level decreased. The largest percentage of variance of PbB in the context of the bivariate model accounted for was 4.23% for Zn, followed by Ca (3.91%) and Fe (2.20%). Supplementary analyses indicated that the between- and within-subject effects did not vary with the age at which participants entered the study, or with the levels of elements at their first measurement. A multivariable analysis using Weighted Quantile Sum Regressions showed that a weighted composite comprised of all the dietary elements had a significant association with PbB when adjusted for Pb in the diet and other covariates and also when adjusted for Pb in house dust; the latter was found to have the strongest association with PbB in earlier analyses. The highest weights were for Ca (0.29), Ni (0.27) and Zn (0.22); these results are generally consistent with those from the mixed model analyses.

Collaborating for Systems Change: A Social Science Framework for Academic Roles in Community Partnerships

Environmental health researchers, government agencies, and community groups have endorsed long-term community-academic partnerships as an effective strategy to support science-based improvements in environmental health. Social sciences concepts, approaches, and methods are fundamental to these translational partnerships. However, appropriate roles for academic partners vary throughout the process of changing systems (policies, practices, programs, etc.). This can complicate planning, evaluating, and sustaining such partnerships. We set forth a conceptual framework for academic partners' roles at different stages of systems change. We apply this framework to three longstanding academic-community partnerships involving National Institute of Environmental Health Sciences Community Outreach and Engagement Cores. We conclude by discussing how the framework can help academic partners tap appropriate expertise, redefine their roles, and evaluate their contributions to community efforts to improve environmental health.

Household interventions for preventing domestic lead exposure in children

BACKGROUND

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children, and trials have tested many household interventions to prevent lead exposure. This is an update of the original review, first published in 2008.

OBJECTIVES

To assess the effects of household interventions for preventing or reducing lead exposure in children, as measured by improvements in cognitive and neurobehavioural development, reductions in blood lead levels and reductions in household dust lead levels.

SEARCH METHODS

In May 2016 we searched CENTRAL, Ovid MEDLINE, Embase, nine other databases and two trials registers: the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov. We also checked the reference lists of relevant studies and contacted experts to find unpublished studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of household educational or environmental interventions, or combinations of interventions to prevent lead exposure in children (from birth to 18 years of age), where investigators reported at least one standardised outcome measure.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information. We assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

We included 14 studies involving 2643 children: 13 RCTs (involving 2565 children) and one quasi-RCT (involving 78 children). Children in all studies were under six years of age. Thirteen studies took place in urban areas of North America, and one was in Australia. Most studies were in areas with low socioeconomic status. Girls and boys were equally represented in all studies. The duration of the intervention ranged from 3 months to 24 months in 12 studies, while 2 studies performed interventions on a single occasion. Follow-up periods ranged from 6 months to 48 months. Three RCTs were at low risk of bias in all assessed domains. We rated two RCTs and one quasi-RCT as being at high risk of selection bias and six RCTs as being at high risk of attrition bias. For educational interventions, we rated the quality of evidence to be high for continuous blood lead levels and moderate for all other outcomes. For environmental interventions, we assessed the quality of evidence as moderate to low. National or international research grants or governments funded 12 studies, while the other 2 did not report their funding sources.No studies reported on cognitive or neurobehavioural outcomes. No studies reported on adverse events in children. All studies reported blood lead level outcomes.We put studies into subgroups according to their intervention type. We performed meta-analyses of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval (CI) -0.09 to 0.12, I² = 0%; 5 studies; N = 815; high quality evidence (log transformed); dichotomous ≥ 10.0 µg/dL (≥ 0.48 µmol/L): risk ratio (RR) 1.02, 95% CI 0.79 to 1.30; I² = 0%; 4 studies; N = 520; moderate quality evidence; dichotomous ≥ 15.0 µg/dL (≥ 0.72 µmol/L): RR 0.60, 95% CI 0.33 to 1.09; I² = 0%; 4 studies; N = 520; moderate quality evidence). Meta-analysis for the dust control subgroup also found no evidence of effectiveness on blood lead levels (continuous: MD -0.15, 95% CI -0.42 to 0.11; I² = 90%; 3 studies; N = 298; low quality evidence (log transformed); dichotomous ≥ 10.0 µg/dL (≥ 0.48 µmol/L): RR 0.93, 95% CI 0.73 to 1.18; I² = 0; 2 studies; N = 210; moderate quality evidence; dichotomous ≥ 15.0 µg/dL (≥ 0.72 µmol/L): RR 0.86, 95% CI 0.35 to 2.07; I² = 56%; 2 studies; N = 210; low quality evidence). After adjusting the dust control subgroup for clustering in meta-analysis, we found no evidence of effectiveness. We could not pool the studies using soil abatement (removal and replacement) and combination intervention groups in a meta-analysis due to substantial differences between studies, and generalisability or reproducibility of the results from these studies is unknown. Therefore, there is currently insufficient evidence to clarify whether soil abatement or a combination of interventions reduces blood lead levels.

AUTHORS' CONCLUSIONS

Based on current knowledge, household educational interventions are ineffective in reducing blood lead levels in children as a population health measure. Dust control interventions may lead to little or no difference in blood lead levels (the quality of evidence was moderate to low, meaning that future research is likely to change these results). There is currently insufficient evidence to draw conclusions about the effectiveness of soil abatement or combination interventions. No study reported on cognitive or neurobehavioural outcomes or adverse events. These patient-relevant outcomes would have been of great interest to draw conclusions for practice.Further trials are required to establish the most effective intervention for preventing lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in low- and middle-income countries and in differing socioeconomic groups in high-income countries.

Recommendations from Lead Poisoning Prevention Program Participants: Best Practices

We present a program evaluation of the Phillips Lead Project, a 5-year study of the effectiveness of culture-specific, peer education in maintaining low blood lead levels of children in an inner-city neighborhood. We conducted focus groups to understand how project participants felt about the various strategies employed by the Lead Project. The purpose of this article is to describe their reactions to the project and make recommendations concerning appropriate educational strategies for lead poisoning prevention projects being undertaken in similar communities. Although this project was a research study, many of its methods, and participants’ reactions to those methods, are relevant to non-research prevention programs and may be generalizable to other health issues besides lead poisoning.

Household interventions for preventing domestic lead exposure in children

BACKGROUND

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children and trials have tested many household interventions to prevent lead exposure. This is an update of the original review by the same authors first published in 2008.

OBJECTIVES

To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development.

SEARCH METHODS

We identified trials through electronic searches of CENTRAL (2012, Issue 1), MEDLINE (1948 to January Week 1 2012), EMBASE (1980 to Week 2 2012), CINAHL (1937 to January 2012), PsycINFO (1887 to January Week 2 2012), ERIC (1966 to January 2012), Sociological Abstracts (1952 to January 2012), Science Citation Index (1970 to 20 January 2012), ZETOC (20 January 2012), LILACS (20 January 2012), Dissertation Abstracts (late 1960s to January 2012), ClinicalTrials.gov (19 January 2012), Current Controlled Trials (19 January 2012), Australian New Zealand Clinical Trials Registry (19 January 2012) and the National Research Register Archive. We also contacted experts to find unpublished studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information.

MAIN RESULTS

We included 14 studies (involving 2656 children). All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. We put studies into subgroups according to their intervention type. We performed meta-analysis of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval (CI) -0.09 to 0.12, I(2) = 0 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): relative risk (RR) 1.02, 95% CI 0.79 to 1.30, I(2)=0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.60, 95% CI 0.33 to 1.09, I(2) = 0). Meta-analysis for the dust control subgroup also found no evidence of effectiveness (continuous: MD -0.15, 95% CI -0.42 to 0.11, I(2) = 0.9 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): RR 0.93, 95% CI 0.73 to 1.18, I(2) =0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.86, 95% CI 0.35 to 2.07, I(2) = 0.56). When meta-analysis for the dust control subgroup was adjusted for clustering, no statistical significant benefit was incurred. The studies using soil abatement (removal and replacement) and combination intervention groups were not able to be meta-analysed due to substantial differences between studies.

AUTHORS' CONCLUSIONS

Based on current knowledge, household educational or dust control interventions are ineffective in reducing blood lead levels in children as a population health measure. There is currently insufficient evidence to draw conclusions about the effectiveness of soil abatement or combination interventions.Further trials are required to establish the most effective intervention for prevention of lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in developing countries and in differing socioeconomic groups in developed countries.

Home safety education and provision of safety equipment for injury prevention (Review)

BACKGROUND

In industrialised countries injuries (including burns, poisoning or drowning) are the leading cause of childhood death and steep social gradients exist in child injury mortality and morbidity. The majority of injuries in pre-school children occur at home but there is little meta-analytic evidence that child home safety interventions reduce injury rates or improve a range of safety practices, and little evidence on their effect by social group.

OBJECTIVES

We evaluated the effectiveness of home safety education, with or without the provision of low cost, discounted or free equipment (hereafter referred to as home safety interventions), in reducing child injury rates or increasing home safety practices and whether the effect varied by social group.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2009, Issue 2) in The Cochrane Library, MEDLINE (Ovid), EMBASE (Ovid), PsycINFO (Ovid), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Social Sciences Citation Index (SSCI), ISI Web of Science: Conference Proceedings Citation Index- Science (CPCI-S), CINAHL (EBSCO) and DARE (2009, Issue 2) in The Cochrane Library. We also searched websites and conference proceedings and searched the bibliographies of relevant studies and previously published reviews. We contacted authors of included studies as well as relevant organisations. The most recent search for trials was May 2009.

SELECTION CRITERIA

Randomised controlled trials (RCTs), non-randomised controlled trials and controlled before and after (CBA) studies where home safety education with or without the provision of safety equipment was provided to those aged 19 years and under, and which reported injury, safety practices or possession of safety equipment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. We attempted to obtain individual participant level data (IPD) for all included studies and summary data and IPD were simultaneously combined in meta-regressions by social and demographic variables. Pooled incidence rate ratios (IRR) were calculated for injuries which occurred during the studies, and pooled odds ratios were calculated for the uptake of safety equipment or safety practices, with 95% confidence intervals.

MAIN RESULTS

Ninety-eight studies, involving 2,605,044 people, are included in this review. Fifty-four studies involving 812,705 people were comparable enough to be included in at least one meta-analysis. Thirty-five (65%) studies were RCTs. Nineteen (35%) of the studies included in the meta-analysis provided IPD. There was a lack of evidence that home safety interventions reduced rates of thermal injuries or poisoning. There was some evidence that interventions may reduce injury rates after adjusting CBA studies for baseline injury rates (IRR 0.89, 95% CI 0.78 to 1.01). Greater reductions in injury rates were found for interventions delivered in the home (IRR 0.75, 95% CI 0.62 to 0.91), and for those interventions not providing safety equipment (IRR 0.78, 95% CI 0.66 to 0.92). Home safety interventions were effective in increasing the proportion of families with safe hot tap water temperatures (OR 1.41, 95% CI 1.07 to 1.86), functional smoke alarms (OR 1.81, 95% CI 1.30 to 2.52), a fire escape plan (OR 2.01, 95% CI 1.45 to 2.77), storing medicines (OR 1.53, 95% CI 1.27 to 1.84) and cleaning products (OR 1.55, 95% CI 1.22 to 1.96) out of reach, having syrup of ipecac (OR 3.34, 95% CI 1.50 to 7.44) or poison control centre numbers accessible (OR 3.30, 95% CI 1.70 to 6.39), having fitted stair gates (OR 1.61, 95% CI 1.19 to 2.17), and having socket covers on unused sockets (OR 2.69, 95% CI 1.46 to 4.96). Interventions providing free, low cost or discounted safety equipment appeared to be more effective in improving some safety practices than those interventions not doing so. There was no consistent evidence that interventions were less effective in families whose children were at greater risk of injury.

AUTHORS' CONCLUSIONS

Home safety interventions most commonly provided as one-to-one, face-to-face education, especially with the provision of safety equipment, are effective in increasing a range of safety practices. There is some evidence that such interventions may reduce injury rates, particularly where interventions are provided at home. Conflicting findings regarding interventions providing safety equipment on safety practices and injury outcomes are likely to be explained by two large studies; one clinic-based study provided equipment but did not reduce injury rates and one school-based study did not provide equipment but did demonstrate a significant reduction in injury rates. There was no consistent evidence that home safety education, with or without the provision of safety equipment, was less effective in those participants at greater risk of injury. Further studies are still required to confirm these findings with respect to injury rates.

Home safety education and provision of safety equipment for injury prevention

BACKGROUND

In industrialised countries injuries (including burns, poisoning or drowning) are the leading cause of childhood death and steep social gradients exist in child injury mortality and morbidity. The majority of injuries in pre-school children occur at home but there is little meta-analytic evidence that child home safety interventions reduce injury rates or improve a range of safety practices, and little evidence on their effect by social group.

OBJECTIVES

We evaluated the effectiveness of home safety education, with or without the provision of low cost, discounted or free equipment (hereafter referred to as home safety interventions), in reducing child injury rates or increasing home safety practices and whether the effect varied by social group.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2009, Issue 2) in The Cochrane Library, MEDLINE (Ovid), EMBASE (Ovid), PsycINFO (Ovid), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Social Sciences Citation Index (SSCI), ISI Web of Science: Conference Proceedings Citation Index- Science (CPCI-S), CINAHL (EBSCO) and DARE (2009, Issue 2) in The Cochrane Library. We also searched websites and conference proceedings and searched the bibliographies of relevant studies and previously published reviews. We contacted authors of included studies as well as relevant organisations. The most recent search for trials was May 2009.

SELECTION CRITERIA

Randomised controlled trials (RCTs), non-randomised controlled trials and controlled before and after (CBA) studies where home safety education with or without the provision of safety equipment was provided to those aged 19 years and under, and which reported injury, safety practices or possession of safety equipment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. We attempted to obtain individual participant level data (IPD) for all included studies and summary data and IPD were simultaneously combined in meta-regressions by social and demographic variables. Pooled incidence rate ratios (IRR) were calculated for injuries which occurred during the studies, and pooled odds ratios were calculated for the uptake of safety equipment or safety practices, with 95% confidence intervals.

MAIN RESULTS

Ninety-eight studies, involving 2,605,044 people, are included in this review. Fifty-four studies involving 812,705 people were comparable enough to be included in at least one meta-analysis. Thirty-five (65%) studies were RCTs. Nineteen (35%) of the studies included in the meta-analysis provided IPD.There was a lack of evidence that home safety interventions reduced rates of thermal injuries or poisoning. There was some evidence that interventions may reduce injury rates after adjusting CBA studies for baseline injury rates (IRR 0.89, 95% CI 0.78 to 1.01). Greater reductions in injury rates were found for interventions delivered in the home (IRR 0.75, 95% CI 0.62 to 0.91), and for those interventions not providing safety equipment (IRR 0.78, 95% CI 0.66 to 0.92).Home safety interventions were effective in increasing the proportion of families with safe hot tap water temperatures (OR 1.41, 95% CI 1.07 to 1.86), functional smoke alarms (OR 1.81, 95% CI 1.30 to 2.52), a fire escape plan (OR 2.01, 95% CI 1.45 to 2.77), storing medicines (OR 1.53, 95% CI 1.27 to 1.84) and cleaning products (OR 1.55, 95% CI 1.22 to 1.96) out of reach, having syrup of ipecac (OR 3.34, 95% CI 1.50 to 7.44) or poison control centre numbers accessible (OR 3.30, 95% CI 1.70 to 6.39), having fitted stair gates (OR 1.61, 95% CI 1.19 to 2.17), and having socket covers on unused sockets (OR 2.69, 95% CI 1.46 to 4.96).Interventions providing free, low cost or discounted safety equipment appeared to be more effective in improving some safety practices than those interventions not doing so. There was no consistent evidence that interventions were less effective in families whose children were at greater risk of injury.

AUTHORS' CONCLUSIONS

Home safety interventions most commonly provided as one-to-one, face-to-face education, especially with the provision of safety equipment, are effective in increasing a range of safety practices. There is some evidence that such interventions may reduce injury rates, particularly where interventions are provided at home. Conflicting findings regarding interventions providing safety equipment on safety practices and injury outcomes are likely to be explained by two large studies; one clinic-based study provided equipment but did not reduce injury rates and one school-based study did not provide equipment but did demonstrate a significant reduction in injury rates. There was no consistent evidence that home safety education, with or without the provision of safety equipment, was less effective in those participants at greater risk of injury. Further studies are still required to confirm these findings with respect to injury rates.

Household interventions for preventing domestic lead exposure in children

BACKGROUND

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children and trials have tested many household interventions to prevent lead exposure. This is an update of the original review by the same authors first published in 2008.

OBJECTIVES

To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development.

SEARCH METHODS

We identified trials through electronic searches of CENTRAL (The Cochrane Library, 2010, Issue 2), MEDLINE (1948 to April Week 1 2012), EMBASE (1980 to 2012 Week 2), CINAHL (1937 to 20 Jan 2012), PsycINFO (1887 to Dec week 2 2011), ERIC (1966 to 17 Jan 2012), Sociological Abstracts (1952 to 20 January 2012), Science Citation Index (1970 to 20 Jan 2012), ZETOC (20 Jan 2012), LILACS (20 Jan 2012), Dissertation Abstracts (late 1960s to Jan 2012), ClinicalTrials.gov (20 Jan 2012), Current Controlled Trials (Jan 2012), Australian New Zealand Clinical Trials Registry (Jan 2012) and the National Research Register Archive. We also contacted experts to find unpublished studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information.

MAIN RESULTS

We included 14 studies (involving 2656 children). All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. We put studies into subgroups according to their intervention type. We performed meta-analysis of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval (CI) -0.09 to 0.12, I(2) = 0 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): relative risk (RR) 1.02, 95% CI 0.79 to 1.30, I(2)=0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.60, 95% CI 0.33 to 1.09, I(2) = 0). Meta-analysis for the dust control subgroup also found no evidence of effectiveness (continuous: MD -0.15, 95% CI -0.42 to 0.11, I(2) = 0.9 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): RR 0.93, 95% CI 0.73 to 1.18, I(2) =0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.86, 95% CI 0.35 to 2.07, I(2) = 0.56). When meta-analysis for the dust control subgroup was adjusted for clustering, no statistical significant benefit was incurred. The studies using soil abatement (removal and replacement) and combination intervention groups were not able to be meta-analysed due to substantial differences between studies.

AUTHORS' CONCLUSIONS

Based on current knowledge, household educational or dust control interventions are ineffective in reducing blood lead levels in children as a population health measure. There is currently insufficient evidence to draw conclusions about the effectiveness of soil abatement or combination interventions.Further trials are required to establish the most effective intervention for prevention of lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in developing countries and in differing socioeconomic groups in developed countries.

Primary prevention of lead exposure--blood lead results at age two years

Objectives: The Philadelphia Lead Safe Homes (LSH) Study was designed to evaluate whether educational and environmental interventions in the first year of life for families of newborns increased knowledge of lead exposure prevention and were associated with less elevation of blood lead levels (BLLs) for these children, when compared to children receiving standard care. Methods: The current study performed descriptive statistics on the second-year BLL data for both groups and compared these using chi-square tests for proportions and unpaired t-tests for means. Results: A BLL result was found for 159 (50.6%) of the 314 LSH cohort children and 331 (52.7%) of the 628 control children (p = 0.1). Mean and standard deviation for age at draw was 23.8 (3.4) months versus 23.6 (3.1) months (P = 0.6). Geometric mean BLLs were 3.7 versus 3.5 µg/dL (P = 0.4). The percentages of the cohort group with a BLL of ≥20, ≥10 and ≥5 μg/dL, respectively, were 0.6%, 5% and 30%; for the controls 1.2%, 6.6%, and 25%. These percentages were not significantly different between groups. Conclusion: A comparison of geometric mean BLLs and percentages above several BLL cut points drawn at age two years in a group of urban newborns benefitting from study interventions versus a group of similar urban children did not yield statistically significant differences. Both groups had relatively lower lead levels when compared to historical cohort groups, which may reflect a continuing downward trend in BLLs in U.S. children. The interventions did result in benefits to the families such as an increase in parental knowledge about lead exposure prevention and in-home wet cleaning activity, and a decrease in lead dust levels in study homes.

Primary prevention of lead exposure: the Philadelphia lead safe homes study

OBJECTIVE

Lead exposure in children can lead to neuropsychological impairment. This study tested whether primary prevention interventions in the newborn period prevent elevated blood lead levels (BLLs).

METHODS

The Philadelphia Lead Safe Homes (LSH) Study offered parental education, home evaluation, and lead remediation to the families of urban newborns. Households were randomized to a standard lead education group or maintenance education group. We conducted home visits at baseline, six months, and 12 months. To compare BLLs, we identified a matched comparison group.

RESULTS

We enrolled and randomized 314 newborns in the intervention component; 110 completed the study. There were few significant differences between the randomized groups. In the combined intervention groups, positive results on visual inspection declined from baseline to 12 months (97.0% to 90.6%, p = 0.007). At baseline, 36.9% of homes were above the U.S. Environmental Protection Agency's lead dust standard, compared with 26.9% at 12 months (p = 0.032), mainly due to a drop in windowsill dust levels. Both groups showed a significant increase in parental scores on a lead education test. Children in the intervention and matched control groups had similar geometric mean initial BLLs (2.6 vs. 2.7, p = 0.477), but a significantly higher percentage of children in the intervention group had an initial blood lead screening compared with those in the matched group (88.9% vs. 84.4%, p = 0.032).

CONCLUSIONS

A study of primary prevention of lead exposure showed a higher blood lead screening rate for the combined intervention groups and mean BLLs at one year of age not statistically different from the comparison group. Most homes had lead hazards. Lead education significantly increased knowledge.

Childhood lead poisoning from the smelter in Torreón, México

Lead concentrations and isotopic compositions in blood samples of 34 children (ages 2-17 years) living within a 113 km(2) area of a silver-zinc-lead smelter plant in Torreón, México were compared to those of associated environmental samples (soil, aerosols, and outdoor and indoor dust) to identify the principal source(s) of environmental and human lead contamination in the area. Lead concentrations of soil and outdoor dust ranged 130-12,050 and 150-14,365 μg g(-1), respectively. Concentrations were greatest near the smelter, with the highest levels corresponding with the prevailing wind direction, and orders of magnitude above background concentrations of 7.3-33.3 μg g(-1). Atmospheric lead depositions in the city varied between 130 and 1350 μg m(-2) d(-1), again with highest rates <1 km from the smelter. Blood lead (PbB) concentrations (11.0±5.3 μg dl(-1)) levels in the children ranged 5.0-25.8 μg dl(-1), which is 3-14 times higher than the current average (1.9 μg dl(-1)) of children (ages 1-5 years) in the US. Lead isotopic ratios ((206)Pb/(207)Pb, (208)Pb/(207)Pb) of the urban dust and soil (1.200±0.009, 2.467±0.003), aerosols (1.200±0.002, 2.466±0.002), and PbB (1.199±0.001, 2.468±0.002) were indistinguishable from each other, as well as those of the lead ores processed at the smelter (1.199±0.007, 2.473±0.007). Consequently, an elevated PbB concentrations of the children in Torreón, as well as in their environment, are still dominated by industrial emissions from the smelter located within the city, in spite of new controls on atmospheric releases from the facility.

Boundary networks and Rochester's "smart" lead law: the use of multidisciplinary information in a collaborative policy process

The Rochester, New York, Coalition to Prevent Lead Poisoning formed in 2001 with the goal of eliminating childhood lead poisoning by 2010. The Coalition recruited diverse community stakeholders into a collaborative process committed to using the best available science. The Coalition successfully infused the debate about a new lead poisoning law with local data, national analyses, and the latest medical research. We argue that this was facilitated by a boundary network of individuals who provided technical input throughout the process. As a result of the Coalition's advocacy, in 2005 the Rochester City Council unanimously passed an ordinance that has been hailed as one of the nation's "smartest" lead laws. Many communities are looking to Rochester's new lead ordinance as a model. Both the process and outcome of this case provide valuable lessons for collaborative efforts to promote scientifically sound local environmental health policy.

Primary prevention of lead poisoning in rural Native American children: behavioral outcomes from a community-based intervention in a former mining region

The current study examined the effectiveness of a community-based lay health advisor intervention, combined with youth engagement, in improving lead poisoning prevention behaviors and associated beliefs in a rural Native American population located in and near a Superfund site containing mining waste. Three sequential (1997, 2000, and 2004) cross-sectional assessments involving in-person interviews with Native American and White caregivers of young children were conducted. Results showed significant improvements over time for Native American, but not for White, for children washing their hands before meals and snacks, and for annual blood lead testing of both Native American and White children. Findings lend support to the value of community-based education for primary prevention of lead poisoning in Native American and rural communities.

Age of greatest susceptibility to childhood lead exposure: a new statistical approach

BACKGROUND

Susceptibility to lead toxicity is often assumed to be greatest during early childhood (e.g., 2 years of age), but recent studies suggest that blood lead concentrations (BPb) taken at 5-7 years of age are more strongly associated with IQ.

OBJECTIVE

We aimed to determine the age of greatest susceptibility to lead exposure using an innovative statistical approach that avoids the problem of correlated serial BPb measurements.

METHODS

We analyzed two cohorts of children that were followed from infancy to 6 years of age in Rochester, New York (n = 211), and Cincinnati, Ohio (n = 251). Serial BPb levels were measured and IQ tests were done when children were 6 years of age. After adjustment for relevant covariates, the ratio of 6-year BPb to 2-year BPb was added to the multiple regression model to test whether the pattern of BPb profiles during childhood had additional effect on IQ.

RESULTS

The ratio of BPb at 6 years to the BPb at 2 years showed a strong effect on IQ (p < .001) when added to the multiple regression model that included the average childhood BPb. IQ decreased by 7.0 points for children whose BPb at 6 years of age was 50% greater than that at 2 years compared with children whose 6-year BPb was 50% less than their 2-year BPb. Similarly, criminal arrest rates were a factor of 3.35 higher for those subjects whose 6-year BPb was 50% higher than their 2-year BPb.

CONCLUSIONS

We conclude that 6-year BPb is more strongly associated with cognitive and behavioral development than is BPb measured in early childhood.

Collaborating for primary prevention: Rochester's new lead law

In December 2005, the City Council of Rochester, New York, passed an amendment to its municipal code requiring inspection for and correction of lead hazards. Local lead poisoning prevention advocates had long recognized the need for stronger lead policy to address Rochester's high rate of childhood lead poisoning. Between 2000 and 2005, a diverse coalition of educators, healthcare professionals, community members, researchers, government officials, and many others worked to develop a strategy for ending childhood lead poisoning in Rochester by 2010. Their experience in defining the issue, mustering resources, and structuring their decision-making processes is informative for other communities seeking to overcome barriers to improved primary prevention policy.

Household interventions for prevention of domestic lead exposure in children

BACKGROUND

Lead poisoning is associated with physical, cognitive and neurobehavioral impairment in children and many household interventions to prevent lead exposure have been trialled.

OBJECTIVES

To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development.

SEARCH STRATEGY

Trials were identified through electronic searches of CENTRAL 2006 (Issue 1), MEDLINE 1966 to March 2006, and thirteen other electronic databases and contacting experts to find unpublished studies.

SELECTION CRITERIA

Randomised and quasi randomised trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported.

DATA COLLECTION AND ANALYSIS

Two reviewers independently reviewed all eligible studies for inclusion, assessed study quality and extracted data. Triallists were contacted to obtain missing information.

MAIN RESULTS

Twelve studies (2239 children) were included. All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. Studies were subgrouped according to their intervention type. Meta-analysis of both continuous and dichotomous data was performed for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: WMD 0.13, 95% CI -0.30, 0.56, I2 = 41.6; dichotomous >/= 10 microg/dL (>/= 0.48 micromol/l): RR 1.02 (95% CI 0.79, 1.30, I2 = 0); dichotomous >/= 15 microg/dL (>/=0.72 micromol/l): RR 0.60, 95% CI 0.33, 1.09, I2 = 0). Meta-analysis of the dichotomous data for the dust control subgroup found no evidence of effectiveness. The studies using soil abatement (removal and replacement) and combination intervention groups were not able to be meta-analysed due to substantial differences between studies.

AUTHORS' CONCLUSIONS

Currently there is no evidence of effectiveness for household interventions for education or dust control measures in reducing blood lead levels in children as a population health measure. There is insufficient evidence for soil abatement or combination interventions. Further trials are required to establish the most effective intervention for prevention of lead exposure. Key elements should include longer term follow up and measures of compliance as well as performing trials in developing countries and differing socio-economic groups in developed countries.

Blood lead concentrations < 10 microg/dL and child intelligence at 6 years of age

BACKGROUND

Few studies provide data directly relevant to the question of whether blood lead concentrations < 10 microg/dL adversely affect children's cognitive function.

OBJECTIVE

We examined the association between blood lead concentrations assessed throughout early childhood and children's IQ at 6 years of age.

METHODS

Children were followed from 6 months to 6 years of age, with determination of blood lead concentrations at 6, 12, 18, and 24 months, and 3, 4, 5, and 6 years of age. At 6 years of age, intelligence was assessed in 194 children using the Wechsler Preschool and Primary Scale of Intelligence-Revised. We used general linear and semiparametic models to estimate and test the association between blood lead concentration and IQ.

RESULTS

After adjustment for maternal IQ, HOME scale scores, and other potential confounding factors, lifetime average blood lead concentration (mean = 7.2 microg/dL; median = 6.2 microg/dL) was inversely associated with Full-Scale IQ (p = 0.006) and Performance IQ scores (p = 0.002). Compared with children who had lifetime average blood lead concentrations < 5 microg/dL, children with lifetime average concentrations between 5 and 9.9 microg/dL scored 4.9 points lower on Full-Scale IQ (91.3 vs. 86.4, p = 0.03). Nonlinear modeling of the peak blood lead concentration revealed an inverse association (p = 0.003) between peak blood lead levels and Full-Scale IQ down to 2.1 microg/dL, the lowest observed peak blood lead concentration in our study.

CONCLUSIONS

Evidence from this cohort indicates that children's intellectual functioning at 6 years of age is impaired by blood lead concentrations well below 10 microg/dL, the Centers for Disease Control and Prevention definition of an elevated blood lead level.

Interpreting and managing blood lead levels of less than 10 microg/dL in children and reducing childhood exposure to lead: recommendations of the Centers for Disease Control and Prevention Advisory Committee on Childhood Lead Poisoning Prevention

Lead is a common environmental contaminant. Lead exposure is a preventable risk that exists in all areas of the United States. In children, lead is associated with impaired cognitive, motor, behavioral, and physical abilities. In 1991, the Centers for Disease Control and Prevention defined the blood lead level that should prompt public health actions as 10 microg/dL. Concurrently, the Centers for Disease Control and Prevention also recognized that a blood lead level of 10 microg/dL did not define a threshold for the harmful effects of lead. Research conducted since 1991 has strengthened the evidence that children's physical and mental development can be affected at blood lead levels of < 10 microg/dL. In this report we provide information to help clinicians understand blood lead levels < 10 microg/dL, identify gaps in knowledge concerning lead levels in this range, and outline strategies to reduce childhood exposures to lead. We also summarize scientific data relevant to counseling, blood lead screening, and lead-exposure risk assessment. To aid in the interpretation of blood lead levels, clinicians should understand the laboratory error range for blood lead values and, if possible, select a laboratory that achieves routine performance within +/-2 microg/dL. Clinicians should obtain an environmental history on all children they examine, provide families with lead-prevention counseling, and follow blood lead screening recommendations established for their areas. As circumstances permit, clinicians should consider referral to developmental programs for children at high risk for exposure to lead and more frequent rescreening of children with blood lead levels approaching 10 microg/dL. In addition, clinicians should direct parents to agencies and sources of information that will help them establish a lead-safe environment for their children. For these preventive strategies to succeed, partnerships between health care providers, families, and local public health and housing programs should be strengthened.

Interactive effects of a DRD4 polymorphism, lead, and sex on executive functions in children

BACKGROUND

Prior studies have examined independent effects of a dopamine receptor D4 polymorphism (DRD4-7) and lead exposure on executive functions but not their interaction or the role of sex as a modifier of their effects.

METHODS

Multivariable analyses were used to examine effects of DRD4-7 genotype, 60-month blood lead level, and sex on spatial working memory, rule learning and reversal, spatial span, and planning for 174 children.

RESULTS

DRD4-7 was associated with poorer spatial working memory, and increasing blood lead levels were associated with impaired rule learning and reversal, spatial span, and planning. Adverse effects of lead on planning and rule learning and reversal were seen primarily for boys. In addition, the effect of lead on rule learning and reversal was evident predominately for those lacking DRD4-7.

CONCLUSIONS

We observed independent effects of DRD4-7 and lead on various executive functions and modifications of lead effects by DRD4 genotype and sex.

Home safety education and provision of safety equipment for injury prevention

BACKGROUND

In industrialised countries injuries are the leading cause of childhood death and steep social gradients exist in child injury mortality and morbidity. The majority of injuries in pre-school children occur at home, but there is little meta-analytic evidence that child home safety interventions improve a range of safety practices or reduce injury rates and little evidence on their effect by social group.

OBJECTIVES

We evaluated the effectiveness of home safety education, with or without the provision of low cost, discounted or free equipment in increasing home safety practices or reducing child injury rates and whether the effect varied by social group.

SEARCH STRATEGY

We searched The Cochrane Library, MEDLINE, EMBASE, CINAHL, DARE, ASSIA, Psychinfo and Web of Science, plus a range of relevant web sites, conference proceedings and bibliographies. We contacted authors of included studies and surveyed a range of organisations.

SELECTION CRITERIA

Randomised controlled trials (RCTs), non-randomised controlled trials and controlled before and after studies where home safety education with or without the provision of safety equipment was provided to those aged 19 years and under, which reported safety practices, possession of safety equipment or injury.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. We attempted to obtain individual participant level data (IPD) for all included studies and summary data and IPD were simultaneoulsy combined in meta-regressions by social and demographic variables.

MAIN RESULTS

Eighty studies were included; 37 of which were included in at least one meta-analysis. Twenty-three (62%) were RCTs and 12 (32%) included in the meta-analysis provided IPD. Home safety education was effective in increasing the proportion of families with safe hot tap water temperatures (OR 1.35, 95% CI 1.01 to 180), functional smoke alarms (OR 1.85, 95% CI 1.24 to 2.75), storing medicines (OR 1.58, 95% CI 1.18 to 2.13) and cleaning products (OR 1.63, 95% CI 1.22 to 2.17) out of reach, syrup of ipecac (OR 3.34, 95% CI 1.50 to 7.44) and poison control centre numbers accessible (OR 3.66, 95% CI 1.84 to 7.27), fitted stair gates (1.26, 95% CI 1.05 to 1.51), socket covers on unused sockets (OR 3.73, 95% CI 1.48 to 9.39) and storing sharp objects out of reach (OR 1.52, 95% CI 1.01 to 2.29). There was a lack of evidence that interventions reduced rates of thermal injuries, poisoning or a range of injuries. There was no consistent evidence that interventions were less effective in families whose children were at greater risk of injury.

AUTHORS' CONCLUSIONS

Home safety education provided most commonly as one-to-one, face-to-face education, in a clinical setting or at home, especially with the provision of safety equipment is effective in increasing a range of safety practices. There is a lack of evidence regarding its impact on child injury rates. There was no consistent evidence that home safety education, with or without the provision of safety equipment was less effective in those at greater risk of injury.

Screening for elevated lead levels in childhood and pregnancy: an updated summary of evidence for the US Preventive Services Task Force

BACKGROUND

In 1996, the US Preventive Services Task Force provided recommendations for routine screening of asymptomatic children and pregnant women for elevated blood lead levels. This review updates the evidence for the benefits and harms of screening and intervention for elevated blood lead in asymptomatic children and pregnant women.

METHODS

We searched Medline, reference lists of review articles, and tables of contents of leading pediatric journals for studies published in 1995 or later that contained new information about the prevalence, diagnosis, natural course, or treatment of elevated lead levels in asymptomatic children aged 1 to 5 years and pregnant women.

RESULTS

The prevalence of elevated blood lead levels among children and women in the United States, like that in the general population, continues to decline sharply, primarily because of marked reductions in environmental exposure, but still varies substantially among different communities and populations. Similar to the findings in 1996, our searches did not identify direct evidence from controlled studies that screening children for elevated blood lead levels results in improved health outcomes, and there was no direct evidence identified from controlled studies that screening improves pregnancy or perinatal outcomes. No new relevant information regarding the accuracy of screening for lead toxicity was identified during the update, and we did not identify evidence that demonstrates that universal screening for blood lead results in better clinical outcomes than targeted screening. Substantial new relevant information regarding the adverse effects of screening and interventions was not identified.

CONCLUSIONS

There is no persuasive evidence that screening for elevated lead levels in asymptomatic children will improve clinical outcomes. For those children who are screened and found to have elevated levels, there is conflicting evidence demonstrating the clinical effectiveness of early detection and intervention.

Trials and tribulations of protecting children from environmental hazards

Society is increasingly aware of the profound impact that the environment has on children's health. Not surprisingly, there is increasing public scrutiny about children's exposures to environmental hazards, especially for disadvantaged children. These trends underscore the ethical imperative to develop a framework to protect children from environmental hazards. Such a framework must include regulations to test new chemicals and other potential hazards before they are marketed, a strategy to conduct research necessary to protect children from persistent hazards that are widely dispersed in their environment, stronger regulatory mechanisms to eliminate human exposures to recognized or suspected toxicants, and guidelines about the ethical conduct of research and the role of experimental trials that test the efficacy and safety of interventions to prevent or ameliorate children's exposure to persistent toxicants or hazards that are widely dispersed in their environment.

Mercy Mercy Me: Social Injustice and the Prevention of Environmental Pollutant Exposures Among Ethnic Minority and Poor Children

Children's lead and pesticide exposures are used as examples to examine social disparities in exposure reduction efforts as well as environmental policies impacting children in poverty and minority children. The review also presents an estimate of the effect of social disparities in lead exposure on standardized test performance. Because including measures of pollutants with potential behavioral effects can alter the observed effects of race/ethnicity, income, and other variables, suggestions are made for including measures of pollutants in longitudinal studies and studies of multiple and cumulative risk. Continued basic research on developmental correlates and effects of pollution exposure, participatory action-research with at-risk and underrepresented populations, and contributions to public awareness and education are important leadership areas for developmental researchers.

A coordinated relocation strategy for enhancing case management of lead poisoned children: outcomes and costs

Controlling residential lead hazards is critical for case management of lead poisoned children. To attain this goal, permanent relocation of the family is sometimes necessary or advisable for many reasons, including poor housing conditions; extensive lead hazards; lack of abatement resources, landlord compliance and local enforcement capacity; and family eviction. During 1996-1998, the Kennedy Krieger Institute implemented a unique capitated program for case management of Baltimore City children with blood lead concentrations (PbB) >19 microg/dL. The Program provided financial, housing, and social work assistance to facilitate relocation as a means of providing safer housing. Nearly half of the Program families relocated with direct assistance, and 28% relocated on their own. The Program evaluation examined the costs and benefits of relocation. Average relocation cost per child was relatively inexpensive (<1,500 dollars). Average relocation time of 5 months (range <2 months to >12 months) was less than the 8-month average time to complete lead hazard control work in 14 city and state programs funded by U.S. HUD. Relocation was associated with (1) a statistically significant decrease in dust lead loadings on floors, windowsills and window troughs that persisted for one year, and (2) statistically significantly greater decreases in children's PbB compared to children who did not relocate from untreated homes. Children relocated to housing that met current Federal residential dust lead standards had statistically significant decreases in blood lead levels. Visual inspection did not consistently identify relocation houses with dust lead levels below current Federal standards, indicating that dust testing should be an essential component of future programs. This will require additional resources for dust testing and possibly cleaning and repairs but is expected to yield additional benefits for children. The findings support recent U.S. CDC case management recommendations suggesting that permanent relocation to safer housing is a viable means to reduce children's lead exposure. The benefits of relocation notwithstanding, 40% of families moved at least twice. Research is needed to better understand how to expedite relocation and encourage families to remain in safe housing. Relocation does not negate owners' and health authorities' responsibilities to address lead hazards in the child's original house in order to protect future occupants.

A randomized, community-based trial of home visiting to reduce blood lead levels in children

OBJECTIVE

The objective of this study was to measure the effectiveness of intensive case management to reduce blood lead levels (BLLs) in children. Lead poisoning remains a common, preventable pediatric condition despite advances in reducing children's BLLs in the United States. Substantial evidence implicates lead paint-contaminated house dust as the most common high-dose source of lead in children's environments. Housekeeping and parental supervision also may contribute to risk for lead exposure.

METHODS

We conducted a community-based, randomized trial of comprehensive education and home visiting for families of children with BLLs 15 to 19 microg/dL. BLLs after 1 year of follow-up were compared for intervention group children, whose families received individualized education that was designed to address specific risks factors in a child's environment, and comparison group children, whose families received customary care, usually 1 or 2 educational visits. Environmental samples were collected at baseline and after 1 year of follow-up for intervention group children and compared with those of comparison group children, collected only at the end of study.

RESULTS

During the follow-up period, parents of intervention group children (n = 92) successfully decreased dust lead levels and significantly improved parent-child interaction and family housekeeping practices compared with comparison group children (n = 83). Overall geometric mean BLLs declined by 47%, and the difference in BLL by group was not significant (9 vs 8.3 microg/dL for intervention versus comparison group children, respectively.) After 1 year, nearly half of enrolled children had BLLs > or = 10 microg/dL.

CONCLUSIONS

Until a reservoir of lead-safe housing is created, programs that educate families to reduce environmental exposure are needed. Although providing families with quantitative information regarding lead contamination may have a role in short-term efforts to prevent lead exposure, these null findings suggest that it has little benefit once BLLs are elevated.

A multihazard, multistrategy approach to home remediation: results of a pilot study

Many residential hazards are disproportionately concentrated in older, urban dwellings and share common underlying causes, such as uncorrected moisture problems and inadequate maintenance and cleaning. Comprehensive and affordable approaches to remediation are needed, but the feasibility and efficacy of such approaches has not been well documented. To address this gap, a multihazard, multimethod intervention, addressing deteriorated lead-based paint and lead dust, vermin, mold, and safety hazards was pilot-tested in a sample of 70 pre-1940 dwellings. Dwellings received paint stabilization, dust lead cleaning, integrated pest management (IPM), mold cleaning, and safety devices, as needed. The median remediation cost for labor and materials was 864.66 dollars (range: 120.00-5235.33 dollars) per dwelling. Environmental conditions were evaluated prior to, immediately following, and an average of 5 months after remediation. Between the baseline and 5-month follow-up periods, significant reductions were achieved in the number of dwellings with multiple (i.e., three or four) problems (75% vs. 23%, P<0.0001); high levels of dust lead on floors and window sills (67% and 46% declines, P<0.01); evidence of cockroaches or rodents (43% and 36% declines, P<0.01); and fire, electrical and/or fall hazards (between 67% and 88% declines, P<0.01). Significant reductions were also observed in the geometric mean (GM) dust lead levels on floors and window sills (13.3 vs. 5.0 microg/ft2 and 210.6 vs. 81.0 microg/ft2, respectively, P<0.0001) and Blatella germanica (Blag1) levels among dwellings with elevated baseline levels (7.7 vs. 0.09 U/g, P<0.0001). Reductions in mold dust levels were of borderline statistical significance (50% decline, P=0.07). The greatest declines in dust lead and Blag1 levels occurred in dwellings having the highest baseline levels and, for Blag1, in dwellings in which occupants attended training sessions. These results indicate that a comprehensive approach to hazard remediation can be highly effective and cost efficient and that overall improvements can be maintained. Further research is needed to clarify the most effective sampling strategies, educational and behavioral interventions, and optimal intervention frequency.

Prolonged exposure to lead lowers the threshold of pentylenetetrazole-induced seizures in rats

PURPOSE

The aim of this work was to study the effects of prolonged exposure to lead on the threshold of experimental seizures induced by pentylenetetrazole (PTZ).

METHODS

The 120 Wistar male rats were allocated randomly into four groups; (A) controls, and lead-treatment groups (B, C, and D) that received lead acetate in the drinking water for a period of 30 days at concentrations of 250, 500, and 1,000 ppm, respectively. After exposure, a trial of PTZ-induced seizures was conducted in all groups, and blood contents of lead were determined by atomic absorption spectrophotometry.

RESULTS

Blood lead contents increased in a dose-dependent manner. Time elapsed to develop the first myoclonic jerk and the tonic-clonic seizure was less in all lead-exposed groups than in controls. This effect was greater in the groups administered 500 and 1,000 ppm of lead. The required doses of PTZ to induce myoclonic jerks and tonic-clonic seizures were lower in lead-exposed rats than in controls.

CONCLUSIONS

We found a reduction in the threshold for seizures in rats whose blood contents of lead were similar to those of humans from some areas of urban centers with high levels of air pollution.

Screening housing to prevent lead toxicity in children

OBJECTIVE

Screening children to identify those with blood lead levels > or = 10 microg/dl fails to protect children from lead-associated cognitive deficits and behavioral problems. To broaden our efforts at primary prevention, screening criteria are needed to identify lead-contaminated housing before children are unduly exposed. The purpose of this study was to identify and validate housing characteristics associated with children having elevated blood lead levels (> or = 10 microg/dl).

METHODS

Two existing studies were used to examine housing characteristics linked with undue lead exposure: a cross-sectional study of 205 children aged 12 to 31 months, and a random sample from a longitudinal study of 276 children followed from 6 to 24 months of age. Logistic regression analysis was conducted to examine the association of children's blood lead levels > or = 10 microg/dl.

RESULTS

The mean age of the 481 children was 17.8 months; 99 (20.6%) had a blood lead concentration of 10 microg/dl or higher. The following characteristics were associated with blood lead concentration > or = 10 microg/dl: floor lead loading > 15 microg/ft2 (odds ratio [OR]=2.2; 95% confidence interval [CI] 1.3, 3.8); rental housing (OR=3.2; 95% CI 1.3, 7.6); poor housing condition (OR=2.1; CI 1.2, 3.6); African American race (OR=3.3; CI 1.9, 6.1); paint chip ingestion (OR=5.8; CI 1.3, 26.5); and soil ingestion (OR=2.2; CI 1.1, 4.2). Housing characteristics including rental status, lead-contaminated floor dust, and housing condition had a range of sensitivity from 47% to 92%; specificity from 28% to 76%; a positive predictive value from 25% to 34%; and a negative predictive value of 85% to 93%.

CONCLUSIONS

Housing characteristics and floor dust lead levels can be used to screen housing to identify lead hazards prior to occupancy, before purchasing a home, or after renovation to prevent children's exposure to lead hazards.

Understanding childhood lead poisoning preventive behaviors: the roles of self-efficacy, subjective norms, and perceived benefits

INTRODUCTION

Understanding individual and social influences on behaviors commonly recommended to prevent lead poisoning in children can guide more effective educational interventions.

METHODS

In-person interviews were conducted with primary caregivers (n = 380) of American Indian and White children aged 1 to 6 living in or near the Tar Creek Superfund site in northeastern Oklahoma. Caregivers' perceived health benefits, self-efficacy, and subjective norms were assessed for four lead poisoning prevention behaviors (i.e., annual blood lead testing, playing in safe areas, washing hands before eating, and dusting with a damp cloth).

RESULTS

Caregivers spoke with their own mothers, spouses, and other female family members most often when they had concerns or worries about taking care of their children. In multivariate models, subjective norms, perceived benefits, and self-efficacy were positively associated with the hand-washing and damp-dusting behaviors, while only self-efficacy was associated with playing in safe areas. None of the variables were found to have significant influence on the blood lead testing behavior.

CONCLUSIONS

Education programs should address individual level factors such as self-efficacy and perceived health benefits but also consider new strategies that incorporate a normative dimension to lead poisoning prevention.

Application of hair-mercury analysis to determine the impact of a seafood advisory

Following an official recommendation in the Faroe Islands that women should abstain from eating mercury-contaminated pilot whale meat, a survey was carried out to obtain information on dietary habits and hair samples for mercury analysis. A letter was sent to all 1180 women aged 26-30 years who resided within the Faroes, and the women were contacted again 1 year later. A total of 415 women responded to the first letter; the second letter resulted in 145 repeat hair samples and 125 new responses. Questionnaire results showed that Faroese women, on average, consumed whale meat for dinner only once every second month, but the frequency and meal size depended on the availability of whale in the community. The geometric mean hair-mercury concentration at the first survey was higher in districts with available whale than in those without (3.03 vs. 1.88 microg/g; P=0.001). The mercury concentration also depended on the frequency of whale meat dinners and on the consumption of dried whale meat. The 36 women who did not eat whale meat at all had a geometric mean hair-mercury concentration of 1.28 microg/g. At the time of the second survey, the geometric mean had decreased to 1.77 microg/g (P<0.001), although whale was now available in all districts. In comparison with previously published data on hair-mercury concentrations in pregnant Faroese women, these results document substantially lower exposures as well as a further decrease temporally associated with the issue of a stricter dietary advisory.

Results from a lay health advisor intervention to prevent lead poisoning among rural Native American children

OBJECTIVES

We tested the effectiveness of a community-based lay health advisor intervention for primary prevention of lead poisoning among Native American children who lived in a former mining area.

METHODS

We conducted cross-sectional population-based blood lead assessments of Native American and White children aged 1 to 6 years and in-person caregiver interviews before (n=331) and after (n=387) a 2-year intervention.

RESULTS

Mean childhood blood lead levels decreased and selected preventive behaviors improved for both Native American and White (comparison) communities. Several short-term outcomes also improved from pre- to postintervention, but only knowledge and hand-washing self-efficacy increased more among Native Americans than among Whites.

CONCLUSIONS

Our findings provide limited support for the effectiveness of lay health advisor interventions as a primary lead poisoning prevention strategy for Native American communities.

Impaired Neuropsychological Functioning in Lead-Exposed Children

Neuropsychological functions were assessed in 174 children participating in a longitudinal study of low-level lead exposure. At age 5 1/2 years, children were administered the Working Memory and Planning Battery of the Cambridge Neuropsychological Testing Automated Battery. Measures of sociodemographic characteristics of the family, prenatal and perinatal risk, quality of caregiving and crowding in the home, and maternal and child intelligence were used as covariates to test the hypothesis that children with higher lifetime average blood lead concentrations would perform more poorly on tests of working memory, attentional flexibility, and planning and problem solving. The lifetime average blood lead level in this sample was 7.2 micrograms per deciliter (mug/dL; range: 0-20 mug/dL). Children with greater exposure performed more poorly on tests of executive processes. In both bivariate and multivariate analyses, children with higher lifetime average blood lead concentrations showed impaired performance on the tests of spatial working memory, spatial memory span, intradimensional and extradimensional shifts, and an analog of the Tower of London task. Many of the significant associations remained after controlling for children's intelligence test scores, in addition to the other covariates. These findings indicate that the effects of pediatric lead exposure are not restricted to global indexes of general intellectual functioning, and executive processes may be at particular risk of lead-induced neurotoxicity.

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.

Recent developments in low-level lead exposure and intellectual impairment in children

In the last decade children's blood lead levels have fallen significantly in a number of countries, and current mean levels in developed countries are in the region of 3 Mu g/dL. Despite this reduction, childhood lead poisoning continues to be a major public health problem for certain at-risk groups of children, and concerns remain over the effects of lead on intellectual development in infants and children. The evidence for lowered cognitive ability in children exposed to lead has come largely from prospective epidemiologic studies. The current World Health Organization/Centers for Disease Control and Prevention blood level of concern reflects this and stands at 10 Mu g/dL. However, a recent study on a cohort of children whose lifetime peak blood levels were consistently less than 10 Mu g/dL has extended the association of blood lead and intellectual impairment to lower levels of lead exposure and suggests there is no safety margin at existing exposures. Because of the importance of this finding, we reviewed this study in detail along with other recent developments in the field of low-level lead exposure and children's cognitive development. We conclude that these findings are important scientifically, and efforts should continue to reduce childhood exposure. However, from a public health perspective, exposure to lead should be seen within the many other risk factors impacting on normal childhood development, in particular the influence of the learning environment itself. Current lead exposure accounts for a very small amount of variance in cognitive ability (1-4%), whereas social and parenting factors account for 40% or more.

Effectiveness of Cleaning and Health Education in Reducing Childhood Lead Poisoning Among Children Residing Near Superfund Sites in Missouri

In this study, the authors evaluated whether a combination of tailored education, lead dust removal by trained cleaning specialists, and family follow-up visits would be more effective than conventional health educational programs in reducing elevated blood lead levels in children living in or near lead mining hazardous waste sites. The authors randomized children between 6 and 72 mo of age with blood lead levels between 10 and 20 microg/dl into 3 groups: standard care, tailored newsletters, or tailored newsletters and specialized cleaning. The authors obtained questionnaires, blood lead levels, and environmental lead samples during initiation and compared them with the same items obtained at 3, 6, and 9 mo follow-up. They used a linear mixed effect model to evaluate the intervention effect. Blood lead levels decreased overall 1.54 microg/dl (12.1%) during the study. The authors found that tailored newsletters and specialized cleaning produced the greatest decline in blood lead levels, but no statistical differences were found among the methodologies. The small decline observed in blood lead levels reduced levels to below 10 microg/dl for 40% of the children.

Identification of sources of lead in children in a primary zinc-lead smelter environment

We compared high-precision lead isotopic ratios in deciduous teeth and environmental samples to evaluate sources of lead in 10 children from six houses in a primary zinc-lead smelter community at North Lake Macquarie, New South Wales, Australia. Teeth were sectioned to allow identification of lead exposure in utero and in early childhood. Blood lead levels in the children ranged from 10 to 42 micro g/dL and remained elevated for a number of years. For most children, only a small contribution to tooth lead can be attributed to gasoline and paint sources. In one child with a blood lead concentration of 19.7 microg/dL, paint could account for about 45% of lead in her blood. Comparison of isotopic ratios of tooth lead levels with those from vacuum cleaner dust, dust-fall accumulation, surface wipes, ceiling (attic) dust, and an estimation of the smelter emissions indicates that from approximately 55 to 100% of lead could be derived from the smelter. For a blood sample from another child, > 90% of lead could be derived from the smelter. We found varying amounts of in utero-derived lead in the teeth. Despite the contaminated environment and high blood lead concentrations in the children, the levels of lead in the teeth are surprisingly low compared with those measured in children from other lead mining and smelting communities.

Effect of a Follow-Up Professional Home Cleaning on Serial Dust and Blood Lead Levels of Urban Children

Children residing in Philadelphia, Pennsylvania, who were enrolled in a clinical trial of oral chelation therapy (n=73) were studied to determine the effects of a follow-up professional lead dust cleaning of their homes 18 mo after an initial cleaning and commencement of therapy. Home dust lead levels were determined from dust-wipe specimens collected from the kitchen and playroom floors, and from a playroom windowsill, prior to, immediately following, and 3 and 6 mo after the second cleaning. Children's blood lead levels were assessed at 3-mo intervals before and after the follow-up cleaning. Professional cleaning produced immediate decreases in dust lead levels; however, dust lead re-accumulated to precleaning levels within 3-6 mo. Frequent, repeated cleanings may be required if blood lead or dust lead levels are to be reduced and sustained at low levels in urban homes.

Environmental health of children

Pediatric primary health care providers are responsible for providing comprehensive care to children. This includes assessing for and identifying the effect of environmental hazards on children's health and managing conditions that may result from exposure to environmental toxins. This article begins by reviewing the unique developmental, biologic, and behavioral characteristics of children and age-specific issues that make them particularly vulnerable to toxins. It then provides the reader with general assessment and management strategies related to environmental toxins, including an assessment tool that can be used in a pediatric primary care office. The qualities of selected toxins that have been implicated in childhood illnesses are discussed. Routes of exposure, signs and symptoms of toxicity, and assessment and management approaches are presented specifically for lead, mercury, environmental tobacco smoke, particulate matter, asbestos, radon, molds, and pesticides. Because prevention is the best intervention in environmental health, the article emphasizes ways pediatric providers can work with caregivers to prevent or minimize exposure.

Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter

BACKGROUND

Despite dramatic declines in children's blood lead concentrations and a lowering of the Centers for Disease Control and Prevention's level of concern to 10 microg per deciliter (0.483 micromol per liter), little is known about children's neurobehavioral functioning at lead concentrations below this level.

METHODS

We measured blood lead concentrations in 172 children at 6, 12, 18, 24, 36, 48, and 60 months of age and administered the Stanford-Binet Intelligence Scale at the ages of 3 and 5 years. The relation between IQ and blood lead concentration was estimated with the use of linear and nonlinear mixed models, with adjustment for maternal IQ, quality of the home environment, and other potential confounders.

RESULTS

The blood lead concentration was inversely and significantly associated with IQ. In the linear model, each increase of 10 microg per deciliter in the lifetime average blood lead concentration was associated with a 4.6-point decrease in IQ (P=0.004), whereas for the subsample of 101 children whose maximal lead concentrations remained below 10 microg per deciliter, the change in IQ associated with a given change in lead concentration was greater. When estimated in a nonlinear model with the full sample, IQ declined by 7.4 points as lifetime average blood lead concentrations increased from 1 to 10 microg per deciliter.

CONCLUSIONS

Blood lead concentrations, even those below 10 microg per deciliter, are inversely associated with children's IQ scores at three and five years of age, and associated declines in IQ are greater at these concentrations than at higher concentrations. These findings suggest that more U.S. children may be adversely affected by environmental lead than previously estimated.

Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter

BACKGROUND

Despite dramatic declines in children's blood lead concentrations and a lowering of the Centers for Disease Control and Prevention's level of concern to 10 microg per deciliter (0.483 micromol per liter), little is known about children's neurobehavioral functioning at lead concentrations below this level.

METHODS

We measured blood lead concentrations in 172 children at 6, 12, 18, 24, 36, 48, and 60 months of age and administered the Stanford-Binet Intelligence Scale at the ages of 3 and 5 years. The relation between IQ and blood lead concentration was estimated with the use of linear and nonlinear mixed models, with adjustment for maternal IQ, quality of the home environment, and other potential confounders.

RESULTS

The blood lead concentration was inversely and significantly associated with IQ. In the linear model, each increase of 10 microg per deciliter in the lifetime average blood lead concentration was associated with a 4.6-point decrease in IQ (P=0.004), whereas for the subsample of 101 children whose maximal lead concentrations remained below 10 microg per deciliter, the change in IQ associated with a given change in lead concentration was greater. When estimated in a nonlinear model with the full sample, IQ declined by 7.4 points as lifetime average blood lead concentrations increased from 1 to 10 microg per deciliter.

CONCLUSIONS

Blood lead concentrations, even those below 10 microg per deciliter, are inversely associated with children's IQ scores at three and five years of age, and associated declines in IQ are greater at these concentrations than at higher concentrations. These findings suggest that more U.S. children may be adversely affected by environmental lead than previously estimated.

A critical evaluation of public health programs at the Bunker Hill Superfund site

Since 1983, the Bunker Hill Superfund site (BHSS) has been the second largest on US Environmental Protection Agency's (EPA) National Priority List for cleanup. Contaminants include millions of tons of Pb, Cd, Hg and As. In 1974, following a bag house fire, 22.1% of young children had blood lead levels >80 microg/dl. In the early 1980s to the present, EPA initiated the cleanup of exterior residential soils and the smelter complex. In 1999, The National Geological Service confirmed that heavy metal pollution had extended from BHSS to Lake Coeur d'Alene (already known earlier) all the way to the Spokane River in Washington State via water borne tributaries linking Idaho and Washington States. This report focuses on public health programs and their results initiated by Federal and State agencies at the BHSS. These programs include blood lead screening, educational programs, exploratory dust control plans, and land transactions. These programs and their results are then evaluated, assessed and critically discussed. The conclusion of this critical evaluation assessment is that the protection of public health has not been adequately addressed or protected by Federal and State agencies.

An evaluation of one-time professional cleaning in homes with lead-based paint hazards

A key challenge in reducing the burden of lead poisoning is to identify cost-effective interventions that minimize lead-based paint hazards. One-time professional cleaning of lead-contaminated dust and debris was conducted in 37 housing units with deteriorated lead-based paint and dust lead hazards. These study units are a subset of a larger cohort of the nearly 3500 housing units enrolled in the Evaluation of the HUD Lead-Based Paint Hazard Control Grant Program. Dust lead loading measurements were taken prior to cleaning, immediately after cleaning (i.e., clearance), and six months, one, two, and three years post-intervention. The cleaning intervention significantly reduced dust lead loadings on floors, windowsills, and window troughs immediately following the work. However, these reductions did not persist at six months and one year post-intervention. Six months and one year post-intervention dust lead loadings are not significantly different from the pre-intervention loadings on either bare floors or windowsills. Although window trough lead loadings declined over 50 percent from pre-intervention to one year post-intervention, the loadings rebounded markedly from the geometric mean at clearance of 101 microgram/ft(2) to 5500 microgram/ft(2) at 6 months and 5790 microgram/ft(2) at one-year post-intervention. These results demonstrate that a single professional cleaning of dust and debris without addressing potential sources of lead dust (such as deteriorated lead-based paint) or repeating the cleaning are unlikely to result in significant and sustained reductions in dust lead loadings. More extensive interventions that address deteriorated lead-based paint, although more expensive, are likely to provide longer term reductions in dust lead loadings. Cleaning strategies, however, may be useful in emergency situations to reduce lead dust hazards when paint repair and other lead hazard control activities cannot be done immediately.