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Household interventions for preventing domestic lead exposure in children

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References

References to studies included in this review

Aschengrau 1998 {published and unpublished data}

Aschengrau A, Hardy S, Mackey P, Pultinas D. The impact of low technology lead hazard reduction activities among children with mildly elevated blood lead levels. Environmental Research 1998;79(1):41‐50.

Boreland 2009 {published and unpublished data}

Boreland F, Lesjak M, Lyle D. Evaluation of home and lead remediation in an Australian mining community. Science of the Total Environment 2009;408(2):202‐8.

Brown 2006 {published and unpublished data}

Brown MJ, McLaine P, Dixon S, Simon P. A randomized, community‐based trial of home visiting to reduce blood lead levels in children. Pediatrics 2006;117(1):147‐53.

Campbell 2011 {published data only}

Campbell C, Tran M, Gracely E, Starkey N, Kersten H, Palermo P, et al. Primary prevention of lead exposure: The Philadelphia Lead Safety Homes Study. Public Health Reports 2011;126(1):76‐88.

Charney 1983 {published and unpublished data}

Charney E, Kessler B, Farfel M, Jackson D. Childhood lead poisoning. A controlled trial of the effect of dust‐control measures on blood lead levels. New England Journal of Medicine 1983;309(18):1089‐93.

Farrell 1998 {published and unpublished data}

Farrell KP, Brophy MC, Chisolm JJ, Rohde CA, Strauss WJ. Soil lead abatement and children's blood lead levels in an urban setting. American Journal of Public Health 1998;88(12):1837‐9.

Hilts 1995 {published and unpublished data}

Hilts SR, Hertzman C, Marion SA. A controlled trial of the effect of HEPA vacuuming on childhood lead exposure. Canadian Journal of Public Health 1995;86(5):345‐50.

Jordan 2003 {published and unpublished data}

Jordan CM, Yust BL, Robison LL, Hannan P, Deinard AS. A randomized trial of education to prevent lead burden in children at high risk for lead exposure: efficacy as measured by blood lead monitoring. Environmental Health Perspectives 2003;111(16):1947‐51.

Lanphear 1996a {published and unpublished data}

Lanphear BP, Winter NL, Apetz L, Eberly S, Weitzman M. A randomized trial of the effect of dust control on children's blood lead levels. Pediatrics 1996;98(1):35‐40.

Lanphear 1999 {published and unpublished data}

Lanphear BP, Eberly S, Howard CR. Long‐term effect of dust control on blood lead concentrations. Pediatrics 2000;106(4):E48.
Lanphear BP, Howard C, Eberly S, Auinger P, Kolassa J, Weitzman M, et al. Primary prevention of childhood lead exposure: A randomized trial of dust control. Pediatrics 1999;103(4 Pt 1):772‐7.

Rhoads 1999 {published and unpublished data}

Lioy PJ, Yiin LM, Adgate J, Weisel C, Rhoads GG. The effectiveness of a home cleaning intervention strategy in reducing potential dust and lead exposures. Journal of Exposure Analysis and Environmental Epidemiology 1998;8(1):17‐35.
Rhoads GG, Ettinger AS, Weisel CP, Buckley TJ, Goldman KD, Adgate J, Lioy PJ. The effect of dust lead control on blood lead in toddlers: a randomized trial. Pediatrics 1999;103(3):551‐5.
Yiin LM, Lioy PJ, Rhoads GG. Impact of home carpets on childhood lead intervention study. Environmental Research 2003;92(2):161‐5.

Sterling 2004 {published and unpublished data}

Sterling DA, Evans RG, Shadel BN, Serrano F, Arndt B, Chen JJ, Harris L. Effectiveness of cleaning and health education in reducing childhood lead poisoning among children residing near superfund sites in Missouri. Archives of Environmental Health 2004;59(3):121‐31.

Wasserman 2002 {published and unpublished data}

Wasserman LR. The effects of a family‐based educational intervention on the prevention of lead poisoning in children. Doctorate of Education Dissertation. Florida International University: Wasserman L, 2002.

Weitzman 1993 {published and unpublished data}

Aschengrau A, Beiser A, Bellinger D, Copenhafer D, Weitzman M. Residential lead‐based‐paint hazard remediation and soil lead abatement: Their impact among children with mildly elevated blood lead levels. American Journal of Public Health 1997;87(10):1698‐702.
Glotzer DE, Weitzman M, Aschengrau A, Freedberg KA. Economic evaluation of environmental interventions for low‐level childhood lead poisoning. Ambulatory Child Health 1997;3(3):255‐67.
Weitzman M, Aschengrau A, Bellinger D, Jones R, Hamlin JS, Beiser A. Lead‐contaminated soil abatement and urban children's blood lead levels. Journal of the American Medical Association 1993;269(13):1647‐54.

References to studies excluded from this review

Aschengrau 1994 {published and unpublished data}

Aschengrau A, Beiser A, Bellinger D, Copenhafer D, Weitzman M. The impact of soil lead abatement on urban children's blood lead levels: phase II results from the Boston Lead‐In‐Soil Demonstration Project. Environmental Research 1994;67(2):125‐48.

Boreland 2006 {published data only}

Boreland F, Lyle DM. Lead dust in Broken Hill homes: effect of remediation on indoor lead levels. Environmental Research 2006;100(2):276‐83.

Dugbatey 2005 {published data only}

Dugbatey K, Croskey V, Evans RG, Narayan G, Osamudiamen O‐E. Lessons from a primary‐prevention program for lead poisoning among inner‐city children. Journal of Environmental Health 2005;68(5):15‐20.

EPA 1996 {published data only}

US Environmental Protection Agency. Effect of in‐home educational intervention on children's blood lead levels in Milwaukee. Technical Report. April 1996.

Marlowe 2001 {published data only}

Marlowe M, Trathen W. The Adventures of Lead Commander: an environmental education program to prevent lead poisoning in young children. Journal of Environmental Education 2001;28(1):19‐23.

Omidpanah 1998 {published and unpublished data}

Omidpanah P. The Effects of Parental Education on Preventing Childhood Lead Poisoning in Inner City Cleveland, Ohio. Online university, http://www.waldenu.edu/c/About/About_231.htm: Walden University, 1998.

Pollak 2002 {published data only}

Pollak J. The lead‐based paint abatement repair and maintenance study in Baltimore: historic framework and study design. Journal of Health Care Law & Policy 2002;6(1):89‐108.

Taha 1999 {published data only}

Taha T, Kanarek MS, Schultz BD, Murphy A. Low‐cost household paint abatement to reduce children's blood lead levels. Environmental Research 1999;81(4):334‐8.

AAP 1998

American Academy of Pediatrics. Screening for elevated blood lead levels. Pediatrics 1998;101(6):1072‐8.

Achenbach 1991

Achenbach TM. Manual for the Child Behavior Checklist. Burlington, VT: University of Vermont, 1991.

Adebanowo 2007

Adebamowo EB, Clark CS, Roda S, Agbede OA, Sridhar MKC, Adebamowo CA. Lead content of dried films of domestic paint currently sold in Nigeria. Science of the Total Environment 2007;388(1‐3):116‐20.

Braubach 2011

Braubach M, Jacobs DE, Ormandy D. Environmental burden of disease associated with inadequate housing: A method guide to the quantification of health effects of selected housing risks in the WHO European region. World Health organisation (Europe)2011:1‐13.

Campbell 2000

Campbell C, Osterhoudt K. Prevention of childhood lead poisoning. Current Opinion on Pediatrics 2000;12(5):428‐37.

Canfield 2003

Canfield RL, Henserson CR, Cory‐Slechta DA, Cox C, Jusko TA, Lanphear BP. Intellectual impairment in children with blood lead concentrations below 10 micrograms per deciliter. New England Journal of Medicine 2003;348:1517‐26.

Chisolm 2001

Chisolm J. The road to primary prevention of lead toxicity in children. Pediatrics 2001;107(3):581‐3.

Clark 2004

Clark S, Grote J, Wilson J, Succop P, Chen M, Glake W, et al. Occurrence and determinants of increases in blood lead levels in children shortly after lead hazard control activities. Environmental Research 2004;96:196‐205.

Clark 2005

Clark CS, Rampal KG, Thuppil V, Chen CK, Clark R, Roda S. The lead content of currently available new residential paint in several Asian countries. Environmental Research 2005;102(1):9‐12.

Dietrich 2004

Dietrich KN, Ware JH, Salganik M, Radcliffe J, Rogan WJ, Rhoads GG, et al. for the Treatment of Lead‐Exposed Children Clinical Trial Group. Effect of chelation therapy on the neuropsychological and behavioral development of lead‐exposed children after school entry. Pediatrics 2004;114(1):19‐26.

Dixon 2009

Dixon SL, Gaitens JM, Jacobs DE, Strauss W, Nagaraja J, Pivetz T, et al. Exposure of U.S. children to residential dust lead, 1999‐2004: II The contribution of lead‐contaminated house dust to children's blood lead levels. Environmental Health Perspectives 2009;117(3):468‐74.

Egger 1997

Egger M, Davey‐Smith G, Schneider M, Minder C. Bias in meta‐analysis detected by a simple, graphical test [see comments). BMJ 1997;315(7109):629‐34.

EHU 2002

Environmental Health Unit. Excessive Lead Exposure ‐ Public Health Guidelines Notice. QLD, Australia: Public Health Services, Queensland Health, 2002.

Fewtrell 2003

Fewtrell L, Kaufman R, Pruss‐Ustan A. Lead ‐ Assessing the Environmental Burden of Disease at National and Local Levels ‐ Environmental Burden of Disease Series. Vol. 2, Geneva: World Health Organisation, 2003.

Gould 2009

Gould E. Childhood lead poisoning: Conservative estimates of the social and economic benefits of lead hazard control. Environmental Health Perspective 2009;117:1162‐67.

Griffiths 1954

Griffiths R. The Abilities of Babies. London: ARICD (The Association for Research in Infant and Child Development), 1954.

Griffiths 1970

Griffiths R. The Abilities of Young Children. London: Child Development and Research Centre, 1970.

Haynes 2002

Haynes E, Lanphear B, Tohn E, Farr N, Rhoads G. The effect of interior lead hazard controls on children's blood concentrations: a systematic evaluation. Environmental Health Perspectives 2002;110(1):103‐7.

Higgins 2002

Higgins JPT, Thompson SG. Quantifying heterogeneity in a meta‐analysis. Statistic in Medicine 2002;21(11):1539‐58.

Higgins 2008

Higgins JPT, White IR, Anzures‐Cabrera J. Meta‐analysis of skewed data: combining results reported on log‐transformed or raw scales. Statistics in Medicine 2008;27(29):6072‐92.

Higgins 2011

Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from www.cochrane‐handbook.org.

Jacobs 2006

Jacobs DE, Nevin R. Validation of a twenty‐year forecast of U.S. childhood lead poisoning: updated prospects for 2010. Environmental Research 2006;102(3):352‐64.

Kordas 2006

Kordas K, Canfield RL, Lopez P, Rosado JL, Vargas GG, Cebrián ME, et al. Deficits in cognitive function and achievement in Mexican first‐graders with low blood lead concentrations. Environmental Research 2006;100(3):371‐86.

Lanphear 1996b

Lanphear BP, Weitzman M, Winter NL, Eberly S, Yakir B, Tanner M, et al. Lead‐contaminated house dust and urban children's blood lead levels. American Journal of Public Health 1996;86(10):1416‐21.

Lanphear 1998

Lanphear BP, Matte TD, Rogers J, Clickner RP, Dietz B, Bornschein RL, et al. The contribution of lead‐contaminated house dust and residential soil to children's blood lead levels. A pooled analysis of 12 epidemiologic studies. Environmental Research 1998;79:51‐68.

Lanphear 2000

Lanphear BP, Eberly S, Howard CR. Long‐term effect of dust control on blood lead concentrations. Pediatrics 2000;106(4):E48.

Lanphear 2005a

Lanphear BP, Hornung R, Khour J, Yolton K, Baghurst P, Bellinger DC, et al. Low‐level environmental lead exposure and children's intellectual function: an international pooled analysis. Environmental Health Perspective 2005;113(7):894‐9.

Lanphear 2005b

Lanphear BP, Hornung R, Ho M. Screening housing to prevent lead toxicity in children. Public Health Reports 2005;120:305‐10.

Lefebvre 2008

Lefebvre C, Manheimer E, Glanville J. Chapter 6: Searching for studies. In: Higgins, JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from www.cochrane‐handbook.org.

Manton 2000

Manton WL, Angle CR, Stanek KL, Reese YR, Kuehnemann TJ. Acquisition and retention of lead by young children. Environmental Research 2000;82(1):60‐80.

Review Manager 2011 [Computer program]

Review Manager (RevMan) Version 5.1. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2011.

Rogan 2001

Rogan WJ, Dietrich KN, Ware JH, Dockery DW, Salganik M, Radcliffe J, et al. for the Treatment of Lead‐Exposed Children Trial Group. The effect of chelation therapy with succimer on neuropsychological development in children exposed to lead. New England Journal of Medicine 2001;344:1421‐6.

Smith 1989

Smith DK, St Martin ME, Lyon MA. A validity study of the Stanford‐Binet: Fourth edition with students with learning disabilities. Journal of Learning Disabilities 1989;22(4):260‐1.

Tong 2000

Tong S, von Schirnding YE, Prapamontol T. Environmental lead exposure: a public health problem of global dimensions. Bulletin of the World Health Organisation 2000;78(9):1068‐77.

Ukoumunne 1999

Ukoumunne OC, Gulliford MC, Chinn S, Sterne JA, Burney PG. Methods for evaluating area‐wide and organisation‐based interventions in health and health care: a systematic review. Health Technology Assessment 1999;3(5):5.

UNEP‐UNICEF 1997

United Nations Environment Programme / United Nations Children's Fund. Childhood lead poisoning ‐ information for advocacy and action. UNEP‐UNICEF information series booklet. 1997. http://www.chem.unep.ch/irptc/Publications/leadpoison/lead_eng.pdf. Geneva / New York: UNEP ‐ UNICEF, (accessed 30 January 2006).

Wechsler 1989

Wechsler D. Wechsler Preschool and Primary Scale of Intelligence‐Revised. San Antonio, Texas: Psychological Corporation, 1989.

Wechsler 1991

Wechsler D. Wechsler Intelligence Scale for Children. 3rd Edition. San Antonio, Texas: Psychological Corporation, 1991.

Wigg 2001

Wigg N. Low‐level lead exposure and children. Journal of Pediatrics and Child Health 2001;37(5):423‐5.

References to other published versions of this review

Yeoh 2008

Yeoh B, Woolfenden S, Wheeler DM, Alperstein G, Lanphear B. Household interventions for prevention of domestic lead exposure in children. Cochrane Database of Systematic Reviews 2008, Issue 2. [DOI: 10.1002/14651858.CD006047.pub2]

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Jump to:

Aschengrau 1998

Methods

RCT
Blinding of outcome assessors for both blood and dust lab analysers
63/402 (16%) enrolled with 41 randomised and 22 subjects at high risk automatically assigned intervention
32/63 blood levels analysed (seven no blood samples, 24 excluded as non‐study interventions undertaken)

Overall, 24/41 from randomised groups analysed (11 intervention and 13 control)

Power calculation performed to determine number of participants (required number not recruited)

Participants

63 children (41 randomised) under four years from Boston located from screening program, mean age 24.5 months, BL blood lead level 16.9 µg/dL

Interventions

Intervention ‐ Low technology lead hazard reduction:
‐remove lead dust
‐loose paint chips
‐HEPA vacuum
‐Parent education re: cleaning

Control ‐ universal outreach and educational activities for both

Outcomes

Blood lead level six months from baseline
(Environmental dust levels)

Notes

Blood lead level and dust levels dropped in both intervention groups compared to control (crude and adjusted) but no statistical significance

Control group and both intervention groups different baseline characteristics and small sample size
Inconsistent parental compliance with housekeeping

Several participants had non‐study interventions and were excluded from analysis in the article

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote from correspondence with author: "an open list of random numbers"

Allocation concealment (selection bias)

High risk

Quote: "open list"

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Quote: "lab analysers were blinded"

Blinding (performance bias and detection bias)
Household dust

Low risk

Quote: "lab analysers were blinded"

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups

Incomplete outcome data (attrition bias)
Household dust

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups

Selective reporting (reporting bias)

Unclear risk

Insufficient information

Other bias

Low risk

The study appears to be free from other sources of bias

Boreland 2009

Methods

RCT
Blinding of outcome assessors for both blood lab analysers
117/365 (32%) enrolled with 103 eligible children randomised and 90 matched by age and blood lead level range (13 were unable to be adequately matched).
88/90 blood levels analysed (two: no blood samples)

Intention to treat (available case analysis)

Power calculation performed to determine number of participants (required number not recruited)

Participants

90 children aged 1.5 to 5.8 years with blood lead level 15 to 29µg/dL on routine screening in Broken Hill, Australia, mean age 3.5 years, mean blood lead level 19.4 µg/dL

Interventions

Intervention ‐ Home remediation work was performed on intervention households and varied depending on assessment of need to provide each house with a "similar level of lead safety". Work may have included: ceiling dust removal, sealing of ceilings, paint stabilisation, replacement of floor coverings/windows and cleaning.

Control ‐ Universal information about minimising lead hazards was provided to both groups.

Outcomes

Blood lead level six months from baseline
(Environmental dust levels)

Notes

Control group received remediation after completion of study.

To examine dose response effect, indoor dust levels were measured to examine the extent in which indoor lead levels were associated with changes in blood lead level.

No significant change in blood lead level between groups.

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote from author, "Children were matched in pairs and then a coin tossed to see which would be the 'case' and have their home re‐mediated first"

Allocation concealment (selection bias)

Unclear risk

Insufficient information

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Nurses collecting blood samples were involved but lab analysers were blinded

Blinding (performance bias and detection bias)
Household dust

Low risk

Technical officers collecting dust samples and lab analysers were blinded

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups

Incomplete outcome data (attrition bias)
Household dust

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups

Selective reporting (reporting bias)

Low risk

The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre‐specified and confirmed by investigator

Other bias

Low risk

The study appears to be free from other sources of bias

Brown 2006

Methods

RCT
Blinding of outcome assessors
175/241 (73%) enrolled
145/175 (83%) analysed
Intention‐to‐treat (available case analysis)
Power calculation performed to determine number of participants (required number recruited)

Participants

175 children under 28 months with blood lead level 15 to 19 µg/dL on routine screening in Rhode Island, mean age 19 months, mean blood lead level 16.5 µg/dL

Interventions

Intervention ‐ Parental Education (with nursing care plan) via five home visits during one year period

Control ‐ one to two educational visits by outreach worker available for both

Outcomes

Blood lead level 12 months from baseline
(Environmental dust levels)
(Questionnaires on lead exposures)
(Parental‐infant interaction scale)

Notes

blood lead level decrease overall over study in participants but no statistical significance
Dust levels decreased for intervention groups but not statistically significant
Questionnaire showed significant improvements in reported housekeeping practices in intervention group
Parent‐Infant scale significantly improved in intervention group

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: "Random numbers table was used to assign cases to either the intervention or the comparison group, sequentially"

Allocation concealment (selection bias)

Low risk

Quote: "Group assignments were sealed into envelopes and unknown to either study personnel or the families until after parental consent was obtained"

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Quote: "The nurses who provided follow up to comparison group children were blinded and nurses that provided care to intervention group were not blinded" and outcome (laboratory) assessors were blinded.

Blinding (performance bias and detection bias)
Household dust

Low risk

Quote: Laboratory analysers were " unaware of group assignment."

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups

Incomplete outcome data (attrition bias)
Household dust

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups

Selective reporting (reporting bias)

Low risk

The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre‐specified and confirmed by investigator

Other bias

Low risk

The study appears to be free of other sources of bias.

Campbell 2011

Methods

RCT

Blinding of outcome assessors not clear

Children:

314/314 (100%) enrolled

279/314 (88.9%) blood lead levels analysed at 12 months of age

Households:

310/310 (100%) enrolled

110/310 (35.5%) Households evaluated at 12 months

Intention‐to‐treat (not performed)

Power calculation performed to determine number of participants (required number recruited)

Participants

314 newborn children from outpatient practices in low income neighbourhoods of Philadelphia (no history of elevated blood lead levels)

Interventions

Intervention ‐ Standard lead poisoning prevention education plus additional extensive education regarding maintaining home in lead‐safe condition and vitis from trained staff at baseline, 6 and 12 months. Cleaning materials provided.

Control‐ Standard lead poisoning prevention education

Outcomes

blood lead levels at 12 months

Housing lead dust levels

Parental Knowledge Assessment

Notes

No significant difference in blood lead levels between groups at 12 months (baseline reading). A two‐year follow‐up is planned for blood lead levels.

A matched comparison group was included in results, receiving community standard for prevention of elevated blood lead levels. This group was not part of the randomisation process.

Number of households with positive dust wipe results (>40 μg/sq.ft. and window >250μg/sq.ft.) not significantly different. Large number households (65%) lost to follow‐up.

Study did not demonstrated an impact on parental knowledge in the children's first blood lead levels at 12 months of age.

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: "Randomised blocks using computer‐generated random numbers"

Allocation concealment (selection bias)

Unclear risk

Quote: "Study coordinator selected next card in the random sequence to randomise that family"

Blinding (performance bias and detection bias)
Blood lead level

High risk

No information provided on blinding

Blinding (performance bias and detection bias)
Household dust

High risk

No information provided on blinding

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Majority of children enrolled (88.9%) had blood lead levels measured at 12months. Not clear if missing outcome data was balanced in numbers across groups.

Incomplete outcome data (attrition bias)
Household dust

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups (59/149 treatment and 51/157 Control)

Selective reporting (reporting bias)

Low risk

blood lead levels outcome data for the Intervention vs Control groups as pre‐specified in the methods not fully included in text. Comparison of blood lead levels at analysis stage was between intervention and control groups combined and a matched comparison group not included in initial randomisation process. This analysis however was pre‐specified in the Methods.

Charney 1983

Methods

Quasi‐RCT (even/odd clinic no. assignment)
Blinding of outcome assessors
78/78 (100%) enrolled
49/78 (63%) analysed
Intention‐to‐treat (unclear)
Power calculation performed to determine number of participants (unclear if required number recruited)

Participants

78 children 15 to 72 months from lead poisoning clinic with blood lead level 30 to 49 µg/dL, mean age 43 months, mean blood lead level 38.6 µg/dL

Interventions

Intervention ‐ Dust control team to wet mop all rooms twice per month and parental education to clean more frequently over 12 months period

Control ‐ Routine advice dust control by mopping given at clinic. Paint stabilisation for both groups

Outcomes

Vblood lead level 12 months from baseline
(Environmental dust levels in intervention homes only)

Notes

Significant change in blood lead level in intervention gp
No significant change in blood lead level in control gp
No persistent improvement in dust lead levels in intervention group
No significant relation between dust level and child's blood lead level

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

High risk

Allocation method alternate based on "even or odd clinic number"

Allocation concealment (selection bias)

High risk

Not used

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Blinding of outcome assessors (laboratory)

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups

Selective reporting (reporting bias)

Unclear risk

Insufficient information

Other bias

Unclear risk

Insufficient information

Farrell 1998

Methods

Cluster RCT by neighbourhoods
Blinding of outcome assessors
Participation rate N/A as community recruitment
182 / 408 (111/263 households) (45%) analysed
No intention‐to‐treat analysis due to those with non‐study interventions excluded
Power calculation performed to determine number of participants (required number recruited)

Participants

408 children living in the included neighbourhoods of Baltimore six months to six years, mean blood lead level 11 µg/dL

Interventions

Intervention ‐ Soil abatement

Control ‐ External paint stabilisation for all in study

Outcomes

Blood lead level two‐year from baseline
(Soil lead levels)

Notes

Blood lead level decreased in both groups at follow up but no statistical significance
Soil lead levels significant decrease in intervention group at one week but re‐accumulated in two‐year follow up

Baseline soil lead levels lower than hypothesised with 54% >1000ppm
No internal household interventions
Adjacent properties not abated

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote "Coin toss"

Allocation concealment (selection bias)

Unclear risk

Insufficient information

Blinding (performance bias and detection bias)
Blood lead level

Unclear risk

Quote: "Specimen collectors and laboratory personnel were blinded to group allocation and analyses were done by the State laboratory which had no interest in the outcome of the study"

Incomplete outcome data (attrition bias)
Blood lead level

Unclear risk

Reasons for missing data not provided

Selective reporting (reporting bias)

Unclear risk

Insufficient information

Other bias

Unclear risk

Insufficient information

Hilts 1995

Methods

Cluster RCT (households in blocks of six stratified by area and blood lead level)
Blinding of outcome assessors
122/176 (69%) enrolled
111/122 (91%) analysed
Intention‐to‐treat (available case analysis)
Power calculation performed to determine number of participants (required number recruited)

Participants

122 households with children under six years in high risk areas (active smelter) identified by 1992 blood screen, mean age 32 months, mean blood lead level 11.6 µg/dL

Interventions

Intervention‐ HEPA vacuuming (seven times in a ten‐month period)

Control ‐ Routine advice regarding maintenance and general lead education provided to both groups

Outcomes

Blood lead level ten months from baseline
(Hand lead and floor dust and lead levels)

Notes

No statistical or clinical significant change in blood lead level even with multiple regression analysis for baseline blood lead level and area

No clinical significance in dust and lead levels

Potential for unit of analysis error

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: "Drew concealed slips of paper numbered 1‐6 without replacement" and assigned blocks and then "coin toss" determined that "odds would be treatment blocks"

Allocation concealment (selection bias)

Low risk

Quote: "Done in central office"

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Quote: "blood specimen collector and lab personnel did not know of group assignments"

Blinding (performance bias and detection bias)
Household dust

Low risk

Quote: "Lab personnel analysing the carpet dust samples were not aware of group assignment"

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups (55/61 treatment and 56/61 control)

Incomplete outcome data (attrition bias)
Household dust

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups

Selective reporting (reporting bias)

Low risk

The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre‐specified and confirmed by investigator

Other bias

Low risk

The study appears to be free of other sources of bias.

Jordan 2003

Methods

RCT
Blinding of outcome assessors
Participation rate N/A as community recruitment
378/607 (62%) analysed
Intention‐to‐treat (unclear)
Power calculation performed to determine number of participants (unclear if required number recruited)

Participants

594 pregnant women and mothers of children zero to three years in neighbourhood of Phillips, Minneapolis, yielding 607 children recruited by door knocking and community information, mean blood lead level <10 µg/dL

Interventions

Intervention ‐ 20 biweekly culturally specific educational session by peer leaders provided individually and three‐monthly boosters until child = three years

Control ‐ Routine state health brochures and home lead assessment and feedback to both groups

Outcomes

blood lead level (capillary until 12 months, venous >12 months) three years from baseline

Notes

No statistically significant change in blood lead level

Dichotomous data
All subjects given financial incentive

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: Random number generator"

Allocation concealment (selection bias)

Low risk

Quote: "Central office"

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Outcome assessors "laboratory" blinded according to author

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Missing outcome data balanced in numbers across groups, with similar reasons for missing data across groups and "no evidence that a missing data pattern that differed by randomization group"

Selective reporting (reporting bias)

Low risk

The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre‐specified and confirmed by investigator

Other bias

Low risk

The study appears to be free of other sources of bias.

Lanphear 1996a

Methods

RCT
Blinding of outcome assessors
104/205 (50%) enrolled (no significant difference in those refused)
96/104 (91%) analysed
Intention to treat (available case analysis)
Power calculation not performed to determine number of participants

Participants

104 children 12 to 31 months recruited from Lead in Dust Study in Rochester, NY, mean age 20 months, mean blood lead level 6.7 µg/dL

Interventions

Intervention ‐ trained interviewer provided brief lead reduction information, cleaning products to families, demonstration on cleaning and instructions on frequency for household cleaning

Control ‐ Brochures on lead poisoning provided to both

Outcomes

Blood lead level seven months from baseline
(Household dust samples)

Notes

No statistical significant difference noted in change in median blood lead level at follow up
No statistical significant change in dust lead levels between groups

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: "Computer random number generator"

Allocation concealment (selection bias)

Low risk

Quote: "Sealed opaque envelopes"

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Quote: "Yes, blood lead specimen collectors and analysers were blinded to group allocation." 

Blinding (performance bias and detection bias)
Household dust

Unclear risk

Author was unable to recall this information

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups and small numbers (8/104)

Incomplete outcome data (attrition bias)
Household dust

Low risk

Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups;

Selective reporting (reporting bias)

Low risk

The study protocol is available and all of the study's pre‐specified outcomes reported in the pre‐specified way.

Other bias

Low risk

The study appears to be free of other sources of bias.

Lanphear 1999

Methods

RCT (also non‐study control to rule out Hawthorne effect)
Blinding of outcome assessors
275/429 (64%) enrolled
245/275 (89%) and 189/275 (69%) analysed at 24 and 48 months, respectively
Intention‐to‐treat (available case analysis)
Power calculation performed to determine number of participants (required number recruited)

Participants

275 children, six months in Rochester area identified by birth data from five urban hospitals, mean age 6 months, mean blood lead level 2.8ug/dL

Interventions

Intervention ‐ Up to eight visits by dust control advisors, cleaning equipment and supplies in 24 month period

Control ‐ Baseline four home visits to both groups

Outcomes

Vblood lead level measured at 6‐ (baseline), 12‐, 18‐, 24‐, 36‐ and 48‐months
(Household dust levels)

Notes

No statistical significant difference in blood lead level at 24 or 48 months between intervention and control groups or percentage of children with raised blood lead level between groups.
Decreased levels of dust in both groups at 24 months but no significant difference between groups

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: Random number generator"

Allocation concealment (selection bias)

Low risk

Quote: "Sealed opaque envelopes"

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Quote: "Blood lead specimen collectors and analysers were blinded to group allocation". 

Blinding (performance bias and detection bias)
Household dust

Low risk

Quote: "Environmental technicians and interviewers blind to group assignment"

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups

Incomplete outcome data (attrition bias)
Household dust

Low risk

Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups

Selective reporting (reporting bias)

Low risk

The study protocol is available and all of the study's pre‐specified outcomes reported in the pre‐specified way.

Other bias

Low risk

The study appears to be free of other sources of bias

Rhoads 1999

Methods

RCT
Blinding of outcome assessors
113/147(77%) enrolled
99/113 (87%) analysed
Intention‐to‐treat (unclear)
Power calculation performed to determine number of participants (required number not recruited)

Participants

113 children, six to 36 months in Jersey City, NY who responded to posters or referred from community clinics, mean age 20 months, mean blood lead level: 11 to 12 µg/dL

Interventions

Intervention ‐ Biweekly assistance with household cleaning (HEPA vacuum and wet mopping) by community staff members for one year

Control ‐ Accident Prevention group given household safety items. Both groups offered education sessions

Outcomes

Blood lead level 12 months from baseline
(Household dust and lead levels)
(Maternal lead knowledge)

Notes

Statistical significant decrease in blood lead level in intervention group compared to controls
Intervention subgroup analysis (39/46 analysed) ‐ statistical significant decrease (26%) in blood lead level in uncarpeted homes compared with no statistical change in carpeted homes
Statistical significant decrease in dust and lead levels between groups
Statistical significant increase in maternal knowledge in intervention group at follow‐up compare with baseline and control

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: "Permutated blocks of varying length"

Allocation concealment (selection bias)

Low risk

Quote: "Sealed envelopes"

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Outcome assessors blinded

Blinding (performance bias and detection bias)
Household dust

Low risk

Outcome assessors blinded

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Reasons for missing data not available but there were relatively small numbers missing with 99/113 analysed.

Incomplete outcome data (attrition bias)
Household dust

Unclear risk

Numbers and reasons for missing data not available

Selective reporting (reporting bias)

Unclear risk

Insufficient information

Other bias

Unclear risk

Insufficient information

Sterling 2004

Methods

RCT
Blinding of outcome assessors
101/132 (76%) enrolled
39/101 (39%) analysed
Intention to treat (unclear)
Power calculation performed to determine number of participants (unclear if required number recruited)

Participants

101 children, six months to six years in Missouri Superfund area identified through community clinics and screening, mean age three years, mean blood lead level 12.7 µg/dL

Interventions

Intervention
1) Three quarterly educational home visit by nurse and six personalised newsletters over nine month period
2) As above plus three quarterly professional cleans with wet mopping, HEPA and carpet shampooing

Control ‐ a standard health education session, baseline home environment assessment and generic brochures for all

Outcomes

Blood lead level three‐monthly until nine months from baseline
(Household lead dust levels)

Notes

Overall decrease in blood lead level in all groups but no statistical difference in blood lead level between groups
No statistical significant change in dust levels between groups

No assessment of variation between subjects lost to follow up and those completing study

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Unclear risk

Method of randomisation unknown

Allocation concealment (selection bias)

Unclear risk

Unknown

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Outcome analysers (laboratory) blinded

Blinding (performance bias and detection bias)
Household dust

Low risk

Outcome analysers (laboratory) blinded

Incomplete outcome data (attrition bias)
Blood lead level

Unclear risk

Numbers and reasons for missing data not available

Incomplete outcome data (attrition bias)
Household dust

Unclear risk

Numbers and reasons for missing data not available

Selective reporting (reporting bias)

Unclear risk

Insufficient information

Other bias

Unclear risk

Insufficient information

Wasserman 2002

Methods

RCT
Blinding of outcome assessors
63/63 (100%) enrolled
50/63 (79%) analysed
Intention‐to‐treat (unclear)
Power calculation not performed to determine number of participants

Participants

Caregivers of 63 children 12 to 36 months of age selected from clients enrolled in Broward County MediPass (Medicaid) who selected Children's Diagnostic and treatment Centre as their health care provider, mean age 22.5 months, mean blood lead level 3 to 4 µg/dL

Interventions

Intervention ‐ education session at clinic consisting of module, video and brochure at first clinic
Control ‐ education session at second clinic

Outcomes

Blood lead level three to four months from baseline
(Parental knowledge ‐ Chicago Lead Knowledge Test)

Notes

No significant difference in blood lead level at follow up between groups
Intervention group had slight decrease in blood lead level versus control group with increase in blood lead level
Statistical significant increase in parental knowledge in intervention group post intervention

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: "Random list of numbers"

Allocation concealment (selection bias)

Low risk

Assigned by central office

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Blinding of outcome assessors (laboratory)

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups

Selective reporting (reporting bias)

Low risk

The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre‐specified and confirmed by investigator

Other bias

Low risk

The study appears to be free of other sources of bias.

Weitzman 1993

Methods

RCT
Blinding of outcome assessors
152/236 (64%) enrolled
149/152 (98%) analysed
Intention‐to‐treat (available case analysis)
Power calculation performed to determine number of participants (required number recruited)

Participants

152 children under four years from high lead risk areas of Boston with finger prick blood lead level 10 to 20 µg/dL identified on screening in 1989, mean age 31.6 months, mean blood lead level 12 to 13 µg/dL

Interventions

Phase I only
Intervention ‐ soil abatement from yard, interior dust abatement, loose interior paint removal
Control A ‐ interior dust abatement, loose interior paint removal
Control B ‐ loose interior paint removal
All received lead education from study staff

Outcomes

Venous blood lead levels 11 months from baseline
(Environmental measures)

Notes

Phase I and phase II of Boston Lead‐In‐Soil trial performed but phase II excluded as no controls
At 11 months post soil abatement, small but significant decrease in blood lead level in intervention groups compared with controls

Risk of bias

Bias

Authors' judgement

Support for judgement

Random sequence generation (selection bias)

Low risk

Quote: "Computer based random number generator"

Allocation concealment (selection bias)

High risk

Allocation performed by one staff member but not actively concealed from other investigators enrolling participants

Blinding (performance bias and detection bias)
Blood lead level

Low risk

Outcome assessors (laboratory analysers) blinded

Blinding (performance bias and detection bias)
Household dust

Low risk

Outcome assessors (laboratory analysers) blinded

Incomplete outcome data (attrition bias)
Blood lead level

Low risk

Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups

Incomplete outcome data (attrition bias)
Household dust

Low risk

Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups

Selective reporting (reporting bias)

Unclear risk

Insufficient information

Other bias

Unclear risk

Insufficient information

Characteristics of excluded studies [ordered by study ID]

Jump to:

Study

Reason for exclusion

Aschengrau 1994

No control group utilised for Phase II

Boreland 2006

Outcome only environmental measures before and after intervention

Dugbatey 2005

Outcome (blood lead levels) measured in mothers rather than children, data not in useable form

EPA 1996

Retrospective data collection on two groups not randomly assigned

Marlowe 2001

Outcome measured using hair lead levels

Omidpanah 1998

Control and Intervention groups from two different study bases

Pollak 2002

Historical control group with no randomisation used

Taha 1999

Retrospective control with no randomisation used

Data and analyses

Open in table viewer
Comparison 1. Education

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Blood lead level (continuous) Show forest plot

5

815

Mean Difference (IV, Random, 95% CI)

0.02 [‐0.09, 0.12]

Analysis 1.1

Comparison 1 Education, Outcome 1 Blood lead level (continuous).

Comparison 1 Education, Outcome 1 Blood lead level (continuous).

2 Blood lead level (dichotomous) ≥10 µg/dL Show forest plot

4

520

Risk Ratio (M‐H, Random, 95% CI)

1.02 [0.79, 1.30]

Analysis 1.2

Comparison 1 Education, Outcome 2 Blood lead level (dichotomous) ≥10 µg/dL.

Comparison 1 Education, Outcome 2 Blood lead level (dichotomous) ≥10 µg/dL.

3 Blood lead level (dichotomous) ≥15 µg/dL Show forest plot

4

520

Risk Ratio (M‐H, Random, 95% CI)

0.60 [0.33, 1.09]

Analysis 1.3

Comparison 1 Education, Outcome 3 Blood lead level (dichotomous) ≥15 µg/dL.

Comparison 1 Education, Outcome 3 Blood lead level (dichotomous) ≥15 µg/dL.

4 Floor dust ‐ hard floor Show forest plot

2

318

Mean Difference (IV, Random, 95% CI)

‐0.07 [‐0.37, 0.24]

Analysis 1.4

Comparison 1 Education, Outcome 4 Floor dust ‐ hard floor.

Comparison 1 Education, Outcome 4 Floor dust ‐ hard floor.

Open in table viewer
Comparison 2. Environmental ‐ Dust control

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Blood lead level (continuous) Show forest plot

3

298

Mean Difference (IV, Random, 95% CI)

‐0.15 [‐0.42, 0.11]

Analysis 2.1

Comparison 2 Environmental ‐ Dust control, Outcome 1 Blood lead level (continuous).

Comparison 2 Environmental ‐ Dust control, Outcome 1 Blood lead level (continuous).

2 Blood lead level (dichotomous ≥10 µg/dL) Show forest plot

2

210

Risk Ratio (M‐H, Random, 95% CI)

0.93 [0.73, 1.18]

Analysis 2.2

Comparison 2 Environmental ‐ Dust control, Outcome 2 Blood lead level (dichotomous ≥10 µg/dL).

Comparison 2 Environmental ‐ Dust control, Outcome 2 Blood lead level (dichotomous ≥10 µg/dL).

3 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.01 Show forest plot

2

204

Risk Ratio (M‐H, Random, 95% CI)

0.93 [0.73, 1.18]

Analysis 2.3

Comparison 2 Environmental ‐ Dust control, Outcome 3 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.01.

Comparison 2 Environmental ‐ Dust control, Outcome 3 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.01.

4 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.1 Show forest plot

2

173

Risk Ratio (M‐H, Random, 95% CI)

0.95 [0.72, 1.24]

Analysis 2.4

Comparison 2 Environmental ‐ Dust control, Outcome 4 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.1.

Comparison 2 Environmental ‐ Dust control, Outcome 4 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.1.

5 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.2 Show forest plot

2

155

Risk Ratio (M‐H, Random, 95% CI)

0.97 [0.72, 1.29]

Analysis 2.5

Comparison 2 Environmental ‐ Dust control, Outcome 5 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.2.

Comparison 2 Environmental ‐ Dust control, Outcome 5 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.2.

6 Blood lead level (dichotomous ≥15 µg/dL) Show forest plot

2

210

Risk Ratio (M‐H, Random, 95% CI)

0.86 [0.35, 2.07]

Analysis 2.6

Comparison 2 Environmental ‐ Dust control, Outcome 6 Blood lead level (dichotomous ≥15 µg/dL).

Comparison 2 Environmental ‐ Dust control, Outcome 6 Blood lead level (dichotomous ≥15 µg/dL).

7 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.01 Show forest plot

2

204

Risk Ratio (M‐H, Random, 95% CI)

0.82 [0.37, 1.81]

Analysis 2.7

Comparison 2 Environmental ‐ Dust control, Outcome 7 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.01.

Comparison 2 Environmental ‐ Dust control, Outcome 7 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.01.

8 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.1 Show forest plot

2

173

Risk Ratio (M‐H, Random, 95% CI)

0.83 [0.34, 2.03]

Analysis 2.8

Comparison 2 Environmental ‐ Dust control, Outcome 8 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.1.

Comparison 2 Environmental ‐ Dust control, Outcome 8 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.1.

9 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.2 Show forest plot

2

155

Risk Ratio (M‐H, Random, 95% CI)

0.75 [0.34, 1.66]

Analysis 2.9

Comparison 2 Environmental ‐ Dust control, Outcome 9 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.2.

Comparison 2 Environmental ‐ Dust control, Outcome 9 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.2.

Study flow diagram
Figures and Tables -
Figure 1

Study flow diagram

Comparison 1 Education, Outcome 1 Blood lead level (continuous).
Figures and Tables -
Analysis 1.1

Comparison 1 Education, Outcome 1 Blood lead level (continuous).

Comparison 1 Education, Outcome 2 Blood lead level (dichotomous) ≥10 µg/dL.
Figures and Tables -
Analysis 1.2

Comparison 1 Education, Outcome 2 Blood lead level (dichotomous) ≥10 µg/dL.

Comparison 1 Education, Outcome 3 Blood lead level (dichotomous) ≥15 µg/dL.
Figures and Tables -
Analysis 1.3

Comparison 1 Education, Outcome 3 Blood lead level (dichotomous) ≥15 µg/dL.

Comparison 1 Education, Outcome 4 Floor dust ‐ hard floor.
Figures and Tables -
Analysis 1.4

Comparison 1 Education, Outcome 4 Floor dust ‐ hard floor.

Comparison 2 Environmental ‐ Dust control, Outcome 1 Blood lead level (continuous).
Figures and Tables -
Analysis 2.1

Comparison 2 Environmental ‐ Dust control, Outcome 1 Blood lead level (continuous).

Comparison 2 Environmental ‐ Dust control, Outcome 2 Blood lead level (dichotomous ≥10 µg/dL).
Figures and Tables -
Analysis 2.2

Comparison 2 Environmental ‐ Dust control, Outcome 2 Blood lead level (dichotomous ≥10 µg/dL).

Comparison 2 Environmental ‐ Dust control, Outcome 3 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.01.
Figures and Tables -
Analysis 2.3

Comparison 2 Environmental ‐ Dust control, Outcome 3 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.01.

Comparison 2 Environmental ‐ Dust control, Outcome 4 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.1.
Figures and Tables -
Analysis 2.4

Comparison 2 Environmental ‐ Dust control, Outcome 4 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.1.

Comparison 2 Environmental ‐ Dust control, Outcome 5 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.2.
Figures and Tables -
Analysis 2.5

Comparison 2 Environmental ‐ Dust control, Outcome 5 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.2.

Comparison 2 Environmental ‐ Dust control, Outcome 6 Blood lead level (dichotomous ≥15 µg/dL).
Figures and Tables -
Analysis 2.6

Comparison 2 Environmental ‐ Dust control, Outcome 6 Blood lead level (dichotomous ≥15 µg/dL).

Comparison 2 Environmental ‐ Dust control, Outcome 7 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.01.
Figures and Tables -
Analysis 2.7

Comparison 2 Environmental ‐ Dust control, Outcome 7 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.01.

Comparison 2 Environmental ‐ Dust control, Outcome 8 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.1.
Figures and Tables -
Analysis 2.8

Comparison 2 Environmental ‐ Dust control, Outcome 8 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.1.

Comparison 2 Environmental ‐ Dust control, Outcome 9 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.2.
Figures and Tables -
Analysis 2.9

Comparison 2 Environmental ‐ Dust control, Outcome 9 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.2.

Summary of findings for the main comparison. Education strategies for preventing domestic lead exposure in children

Education strategies for preventing domestic lead exposure in children

Patient or population: Children
Settings: Households
Intervention: Education strategies for prevention of domestic lead exposure
Comparison: Regular environment

Outcomes

Illustrative comparative risks* (95% CI)

Relative effect
(95% CI)

No of Participants
(studies)

Quality of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

Regular environment

Education strategies for prevention of domestic lead exposure

Blood lead level (continuous)
Blood lead levels after intervention Scale from: 0 to 30
Follow‐up: 6 to 18 months

The mean blood lead level (continuous) ranged across control groups from
1.24 to 2.13 µg/dL1,2

The mean blood lead level (continuous) in the intervention groups was
0.02 higher
(0.09 lower to 0.12 higher)

814
(5 studies)

⊕⊕⊕⊕
high

Blood lead level (dichotomous)10 µg/dL
blood lead level
Follow‐up: 6 to 18 months

Medium risk population3

RR 1.02
(0.79 to 1.3)5

520
(4 studies)

⊕⊕⊕⊝
moderate4,5

238 per 10004

243 per 1000
(188 to 309)4

Blood lead level (dichotomous)15 µg/dL
blood lead level
Follow‐up: 6 to 18 months

Medium risk population3

RR 0.6
(0.33 to 1.09)

520
(4 studies)

⊕⊕⊕⊝
moderate4,5

110 per 10004

66 per 1000
(36 to 120)4

Floor dust ‐ hard floor (continuous)
Floor dust lead levels

Scale from: 0 to 40
Follow‐up: 6 to 18 months

The mean floor dust level ‐ hard floor ‐ ranged across control groups from
1.65 to 2.28 µg/ft2

The mean floor dust level ‐ hard floor ‐ in the intervention groups was
0.07 lower
(0.37 lower to 0.24 higher)

318
(2 studies)

⊕⊕⊕⊝
moderate6

Cognitive and neurobehavioural outcomes ‐ not reported

See comment

See comment

Not estimable

See comment

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: Confidence interval; RR: Risk ratio;

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

1 Change in blood lead level
2 These are logged values
3 Baseline based on median of control groups
4 Total number of events less than 300
5 95% CI around pooled estimate includes no effect and appreciable harm or benefit
6 Total population is less than 400

Figures and Tables -
Summary of findings for the main comparison. Education strategies for preventing domestic lead exposure in children
Summary of findings 2. Environmental strategies (dust control) for preventing domestic lead exposure in children

Environmental strategies (dust control) for preventing domestic lead exposure in children

Patient or population: Children
Settings: Households
Intervention: Environmental strategies (dust control)
Comparison: Regular environment

Outcomes

Illustrative comparative risks* (95% CI)

Relative effect
(95% CI)

No of Participants
(studies)

Quality of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

Control

Environmental strategies (Dust Control)

Blood lead level (continuous)
Blood lead level at end of duration. Scale from: 0 to 30
Follow‐up: 6 to 18 months

The mean blood lead level (continuous) ranged across control groups from
2.4 to 2.9 µg/dL1

The mean blood lead level (continuous) in the intervention groups was
0.15 lower
(0.42 lower to 0.11 higher)

298
(3 studies)

⊕⊕⊕⊝
moderate2

Blood lead level (dichotomous10 µg/dL)
blood lead level
Follow‐up: 6 to 18 months

Medium risk population3

RR 0.93
(0.73 to 1.18)

210
(2 studies)

⊕⊕⊕⊝
moderate4

573 per 10004

533 per 1000
(418 to 676)4

Blood lead level (dichotomous15 µg/dL)
blood lead level
Follow‐up: 6 to 18 months

Medium risk population3

RR 0.86
(0.35 to 2.07)5

210
(3 studies)

⊕⊕⊕⊝
moderate4,5

205 per 10004

176 per 1000
(72 to 424)4

Cognitive and neurobehavioural outcomes ‐ not reported

See comment

See comment

Not estimable

See comment

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: Confidence interval; RR: Risk ratio;

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

1 Change in blood lead level
2 Total population size less than 400
3 Baseline based on median of control groups
4 Total number of events less than 300,
5 95% CI around pooled estimate includes no effect and appreciable harm or benefit

Figures and Tables -
Summary of findings 2. Environmental strategies (dust control) for preventing domestic lead exposure in children
Table 1. Mean blood lead level and age at baseline

Study ID

Aschengrau 1998

Boreland 2009

Brown 2006

Campbell 2011

Charney 1983

Farrell 1998

Hilts 1995

Jordan 2003

Lanphear 1996

Lanphear 1999

Rhoads 1999

Sterling 2004

Wasserman 2002

Weitzman 1993

Mean blood lead level at baseline (µg/dL)

15‐19

15‐19

15‐19

2.6‐2.7

>20

10‐14

10‐14

<10

 

<10

<10

10‐14

10‐14

<10

10‐14

Mean age at baseline

(months)

24‐36

> 36

12‐24

8‐14

> 36

6‐72

24‐36

<12

12‐24

<12

12‐24

> 36

12‐24

24‐36

Figures and Tables -
Table 1. Mean blood lead level and age at baseline
Table 2. Intervention type by study

Study ID

Education

Dust control

Soil abatement

Combination

Aschengrau 1998

Yes

Boreland 2009

Yes

Brown 2006

Yes

Campbell 2011

Yes

Charney 1983

Yes

Farrell 1998

Yes

Hilts 1995

Yes

Jordan 2003

Yes

Lanphear 1996

Yes

Lanphear 1999

Yes

Rhoads 1999

Yes

Sterling 2004

Yes

Wasserman 2002

Yes

Weitzman 1993

Yes

Figures and Tables -
Table 2. Intervention type by study
Table 3. Outcome measures by study

Study ID

Blood lead ‐ continuous

Blood lead ‐ dichotomous

Hard floor lead

Carpet lead

Other

Aschengrau 1998

Yes

Yes

Boreland 2009

Yes

Brown 2006

Yes

Yes

Parent‐Child Interaction scale

Campbell 2011

Yes

Yes

Chicago Parents Knowledge Test

Charney 1983

Yes

Yes

Farrell 1998

Total effect (blood lead levels)

Hilts 1995

Yes

Yes

Yes

Jordan 2003

Yes

Lanphear 1996

Yes

Yes

Yes

Yes

Lanphear 1999

Yes

Yes

Yes

Yes

Rhoads 1999

Yes

Yes

Maternal knowledge lead poisoning

Sterling 2004

Yes

Wasserman 2002

Yes

Yes

Chicago Parents Knowledge Test

Weitzman 1993

Yes

Figures and Tables -
Table 3. Outcome measures by study
Comparison 1. Education

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Blood lead level (continuous) Show forest plot

5

815

Mean Difference (IV, Random, 95% CI)

0.02 [‐0.09, 0.12]

2 Blood lead level (dichotomous) ≥10 µg/dL Show forest plot

4

520

Risk Ratio (M‐H, Random, 95% CI)

1.02 [0.79, 1.30]

3 Blood lead level (dichotomous) ≥15 µg/dL Show forest plot

4

520

Risk Ratio (M‐H, Random, 95% CI)

0.60 [0.33, 1.09]

4 Floor dust ‐ hard floor Show forest plot

2

318

Mean Difference (IV, Random, 95% CI)

‐0.07 [‐0.37, 0.24]

Figures and Tables -
Comparison 1. Education
Comparison 2. Environmental ‐ Dust control

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Blood lead level (continuous) Show forest plot

3

298

Mean Difference (IV, Random, 95% CI)

‐0.15 [‐0.42, 0.11]

2 Blood lead level (dichotomous ≥10 µg/dL) Show forest plot

2

210

Risk Ratio (M‐H, Random, 95% CI)

0.93 [0.73, 1.18]

3 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.01 Show forest plot

2

204

Risk Ratio (M‐H, Random, 95% CI)

0.93 [0.73, 1.18]

4 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.1 Show forest plot

2

173

Risk Ratio (M‐H, Random, 95% CI)

0.95 [0.72, 1.24]

5 Blood lead level (dichotomous ≥10 µg/dL) ICC 0.2 Show forest plot

2

155

Risk Ratio (M‐H, Random, 95% CI)

0.97 [0.72, 1.29]

6 Blood lead level (dichotomous ≥15 µg/dL) Show forest plot

2

210

Risk Ratio (M‐H, Random, 95% CI)

0.86 [0.35, 2.07]

7 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.01 Show forest plot

2

204

Risk Ratio (M‐H, Random, 95% CI)

0.82 [0.37, 1.81]

8 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.1 Show forest plot

2

173

Risk Ratio (M‐H, Random, 95% CI)

0.83 [0.34, 2.03]

9 Blood lead level (dichotomous ≥15 µg/dL) ICC 0.2 Show forest plot

2

155

Risk Ratio (M‐H, Random, 95% CI)

0.75 [0.34, 1.66]

Figures and Tables -
Comparison 2. Environmental ‐ Dust control