Low-cost household paint abatement to reduce children's blood lead levels

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 We also searched Google Scholar, checked the reference lists of relevant studies and contacted experts to identify unpublished studies.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.

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.

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.

Evaluation of home lead remediation in an Australian mining community

In 1994 a comprehensive program was established to reduce children's blood lead levels in Broken Hill, NSW, Australia. Home remediation (abatement of lead hazards in a child's home) was included as part of a case management strategy for children with blood lead levels >or=15 microg/dL. Children with blood lead levels >or=30 microg/dL were offered immediate home remediation. Children with blood lead levels of 15-29 microg/dL were allocated to 'immediate' or 'delayed' home remediation; a subset of these participated in a randomized controlled trial (RCT) to evaluate the effectiveness of home remediation for reducing blood lead levels. One hundred and seventeen children received home remediation. One hundred and thirteen returned for follow-up blood tests, 88 of whom participated in the RCT. On average children's blood lead levels decreased by 1.7 microg/dL (10%) in the 6 months after remediation and by 2.2 microg/dL (13%) in the 6-12 months after remediation. However, remediation did not significantly change the rate of decline in blood lead levels (P=0.609). There was no evidence of association between change in children's blood lead levels and changes in lead loading in their homes. The results are consistent with the published literature, which suggests that home remediation does not reduce children's exposure to lead sufficiently to cause a moderate or greater decrease in their blood lead level. In communities where lead is widely dispersed, the study suggests that it is important to assess potential sources and pathways by which children are exposed to lead when developing an intervention plan, and the need for multiple interventions to effectively reduce blood lead levels. The findings reinforce the ongoing need for rigorous epidemiological evaluation of lead management programs to improve the evidence base, and for effective primary prevention to avoid children being exposed to lead in the first place.

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.

Exposure to lead and length of time needed to make homes lead-safe for young children

OBJECTIVES

We determined the length of time needed to make homes lead-safe in a population of children aged 0 to 6 years with blood lead levels (BLLs) of 20 micrograms per deciliter (mug/dL) or greater. Reducing this time would reduce children's exposure to lead.

METHODS

Data came from the Wisconsin Childhood Lead Poisoning Prevention Program's comprehensive blood lead surveillance system. Analysis was restricted to children whose first BLL test value during 1996-1999 was between 20 and 40 mug/dL and for whom housing intervention data were available (n=382).

RESULTS

The median length of time required to make a home lead-safe was 465 days. Only 18% of children lived in homes that were made lead-safe within 6 months; 45% lived in homes requiring more than 18 months to be lead-safe.

CONCLUSIONS

Efforts are needed to reduce the time it takes to make a home lead-safe. Although abatement orders always include time limits, improved compliance with the orders must be enforced. Greater emphasis should be placed on securing lead-safe or lead-free housing for families, thus reducing lead exposure.

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.

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.

Trace elements in blood and serum of Swedish adolescents: relation to gender, age, residential area, and socioeconomic status

The influence of gender, age, residential area, and socioeconomic status on the blood and serum levels of 13 trace elements was studied in boys and girls living in two Swedish cities with different socioeconomic and environmental characters. The same groups of adolescents were sampled twice, at ages 15 (n=372) and 17 (n=294) years. All the investigated factors were shown to be of importance. Age was important for most elements; e.g., copper levels in both blood and serum increased in girls, and selenium increased in serum from both genders. Lead decreased approximately 10% in blood from the first to the second sampling, and cadmium increased in blood, however not in nonsmokers. The age factor may also reflect temporal changes in environmental exposure, especially for nonessential elements. Girls had higher levels of cobalt and copper, while lead in blood was higher in boys. Smoking girls had higher copper levels than nonsmoking girls. Residential area influenced all elements. The teenagers with university-educated mothers had higher levels of cadmium in blood than those with only primary school-educated mothers.

Prevention of childhood lead poisoning

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