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Interventions to improve water quality and supply, sanitation and hygiene practices, and their effects on the nutritional status of children

  1. Alan D Dangour1,*,
  2. Louise Watson1,
  3. Oliver Cumming2,
  4. Sophie Boisson3,
  5. Yan Che4,
  6. Yael Velleman5,
  7. Sue Cavill6,
  8. Elizabeth Allen7,
  9. Ricardo Uauy1

Editorial Group: Cochrane Public Health Group

Published Online: 1 AUG 2013

Assessed as up-to-date: 12 NOV 2012

DOI: 10.1002/14651858.CD009382.pub2


How to Cite

Dangour AD, Watson L, Cumming O, Boisson S, Che Y, Velleman Y, Cavill S, Allen E, Uauy R. Interventions to improve water quality and supply, sanitation and hygiene practices, and their effects on the nutritional status of children. Cochrane Database of Systematic Reviews 2013, Issue 8. Art. No.: CD009382. DOI: 10.1002/14651858.CD009382.pub2.

Author Information

  1. 1

    London School of Hygiene & Tropical Medicine, Department of Population Health, London, UK

  2. 2

    London School of Hygiene & Tropical Medicine, Environmental Health Group, London, UK

  3. 3

    London School of Hygiene & Tropical Medicine, Department of Disease Control, London, UK

  4. 4

    Shanghai Institute of Planned Parenthood Research (SIPPR), Centre for Clinical Research and Training, Shanghai, China

  5. 5

    WaterAid, Policy and Campaigns, London, UK

  6. 6

    WaterAid, Technical Support Unit, London, UK

  7. 7

    London School of Hygiene & Tropical Medicine, Medical Statistics Department, London, UK

*Alan D Dangour, Department of Population Health, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. Alan.Dangour@lshtm.ac.uk.

Publication History

  1. Publication Status: New
  2. Published Online: 1 AUG 2013

SEARCH

 

Summary of findings    [Explanations]

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

 
Summary of findings for the main comparison.

Water, sanitation and hygiene interventions compared with usual practice for child nutrition outcomes

Population: households

Settings: rural and urban communities in low- and middle-income countries

Interventions: to improve water quality and supply, sanitation and hygiene practices

Comparison: usual practice

Quality of evidence: none of the included studies were of high methodological quality

Relative effect
(95% CI)
No of participants
(studies)

Weight-for-age pooled estimate (RCTs only)MD 0.05 (-0.01 to 0.12)4627 (5)

Du Preez 2010 (cRCT)MD 0.21 (-0.07 to 0.49)332

Du Preez 2011 (cRCT)MD -0.01 (-0.23 to 0.21)525

McGuigan 2010 (cRCT)MD 0.26 (-0.01 to 0.53)760

Luby 2004 (cRCT)MD 0.01 (-0.10 to 0.12)873

Luby 2006 (Soap) (cRCT)MD 0.05 (-0.13 to 0.23)533

Luby 2006 (Soap & Floc) (cRCT)MD 0.07 (-0.11 to 0.25)550

Luby 2006 (Floc & Bleach) (cRCT)MD 0.03 (-0.12 to 0.18)1054

Ahmed 1993P < 0.05 at end for a difference

between groups (favouring intervention)
298

Arnold 2009MD -0.06 (-0.23 to 0.11)877

Bowen 2012MD -0.06 (-0.27 to 0.15)461

Hasan 1989No statistically significant differences

between intervention and control group
405

Langford 2011MD -0.24 (-0.76 to 0.28)88

Weight-for-height pooled estimate (RCTs only)MD 0.02 (-0.07 to 0.11)4622 (5)

Du Preez 2010 (cRCT)MD 0.08 (-0.20 to 0.36)332

Du Preez 2011 (cRCT)MD -0.11 (-0.30 to 0.08)522

McGuigan 2011 (cRCT)MD 0.15 (-0.15 to 0.45)760

Luby 2004 (cRCT)MD 0.03 (-0.32 to 0.38)873

Luby 2006 (Soap) (cRCT)MD 0.02 (-0.20 to 0.24)533

Luby 2006 (Soap & Floc) (cRCT)MD 0.06 (-0.16 to 0.28)549

Luby 2006 (Floc & Bleach) (cRCT)MD 0.02 (-0.20 to 0.24)1053

Arnold 2009MD -0.07 (-0.28 to 0.14)872

Hasan 1989No statistically significant differences

between intervention and control group
405

Langford 2011MD -0.11 (-0.53 to 0.31)88

Height-for-age pooled estimate (RCTs only)MD 0.08 (0.00 to 0.16)4627 (5)

Du Preez 2010 (cRCT)MD 0.28 (-0.06 to 0.62)332

Du Preez 2011 (cRCT)MD 0.11 (-0.19 to 0.41)525

McGuigan 2011 (cRCT)MD 0.22 (-0.04 to 0.48)760

Luby 2004 (cRCT)MD -0.01 (-0.37 to 0.35)873

Luby 2006 (Soap) (cRCT)MD 0.08 (-0.13 to 0.29)534

Luby 2006 (Soap & Floc) (cRCT)MD 0.06 (-0.12 to 0.24)549

Luby 2006 (Floc & Bleach) (cRCT)MD 0.04 (-0.08 to 0.16)1054

Arnold 2009MD 0.04 (-0.19 to 0.27)876

Bowen 2012MD -0.08 (-0.29 to 0.13)461

Fenn 2012MD 0.22 (0.11 to 0.33)1899

Hasan 1989No statistically significant differences

between intervention and control group
405

Langford 2011MD -0.13 (-0.54 to 0.28)88

CI: confidence interval; cRCT: cluster-randomised controlled trial; MD: mean difference; RCT: randomised controlled trial; Floc: flocculent disinfectant

 

Background

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

Water, sanitation and hygiene (WASH) interventions such as provision of clean piped drinking water, enhanced facilities for excreta disposal and the promotion of handwashing with soap are frequently implemented to improve health and reduce infectious disease incidence and may be linked to child development outcomes. There are no published systematic reviews investigating the impact of WASH interventions on medium- to long-term markers of health in childhood, such as measures of physical growth and nutritional sufficiency. This review assesses the strength of evidence linking WASH interventions with measures of child nutritional status.

 

Description of the condition

In 2010 it was estimated that undernutrition (insufficient energy intake) affected approximately 925 million people worldwide (FAO 2010), and the global estimates of people with specific nutrient insufficiencies (for example iron and iodine) are in excess of 2 billion (SCN 2004). Insufficient intake of dietary energy, minerals and vitamins is estimated to be the underlying cause of 45% of all child deaths (approximately 3.1 million deaths per year) (Black 2013). This figure includes estimates of the negative effects of undernutrition on pregnant women, which can cause poor foetal growth (intra-uterine growth retardation) and low birthweight. The period from conception to 24 months of age is widely recognised as a critical window for the prevention of undernutrition (Black 2013). Millennium Development Goal 4 (MDG 4) is to reduce by two-thirds the mortality rate of children under five years of age, and ensuring good nutritional status is crucial for the attainment of this goal.

Globally, an estimated 26% of children under the age of five years (165 million) suffer from chronic undernutrition manifested as short height for their age (or stunting) and 8% (52 million) suffer from acute undernutrition manifested by extreme thinness or wasting (low weight-for-height); by far the largest numbers of undernourished children live in South Asia and Sub-Saharan Africa (UNICEF/WHO/World Bank 2012). The long-term consequences of chronic undernutrition include reduced school attendance and diminished health and economic potential. One target for Millennium Development Goal 1 (MDG 1) is to reduce by half the proportion of people who suffer from hunger, but to date progress towards this goal has been slow (UNICEF/WHO/World Bank 2012). 

Nutritional status in children is normally evaluated by assessing physical growth performance (via anthropometry) or micronutrient status (clinical signs of deficiency or blood measures). Various standardised methods are available for the assessment of nutritional status. There are both direct and indirect causes of undernutrition in children. The two immediate causes of undernutrition are inadequate dietary intake and disease, which interact in a complex manner and manifest as either chronic undernutrition (stunting) or in acute situations as extreme thinness (wasting). Underlying these immediate causes are a multitude of indirect factors that contribute to nutritional status, such as food security, child-care practices, maternal education, access to health services and water, hygiene and sanitation conditions. Ultimately, these factors are embedded in the larger political, economic, social and cultural environment.

 

Description of the intervention

The integral role in health of safe water, sanitary disposal of human waste and personal hygiene has long been recognised (Esrey 1992). One target for Millennium Development Goal 7 (MDG 7) is to reduce by half the proportion of people without access to safe drinking water and basic sanitation. Activities linked to this goal aim to increase access to improved drinking water and sanitation. However, the possible benefits to health and nutrition of meeting the MDG 7 safe water and sanitation targets are rarely discussed.

Currently approximately 2.5 billion people do not have access to improved sanitation, that is sanitation which ensures the hygienic separation of human excreta from human contact, and they rely on facilities such as unsafe flush or pour flush (to the street, yard, plot, open sewer, ditch or other location), a pit latrine without a slab or platform, a bucket and hanging latrine. Approximately 1.1 billion people have no sanitation facilities at all and practice open defecation (WHO/UNICEF 2012). Approximately 783 million people do not have access to improved drinking water sources (WHO/UNICEF 2012). Progress towards MDG 7 is on track for access to safe water but will fall well short for provision of basic sanitation (WHO/UNICEF 2012) and there are major differences between and within countries and regions.

Water, sanitation and hygiene (WASH) interventions are defined in this review as follows:

  • Water quality is any intervention to improve the microbiological quality of drinking water, including removing or inactivating microbiological pathogens (via household, community or water source level water treatment systems involving filtration, sedimentation, chemical treatment, heat treatment or ultraviolet (UV) radiation) and protecting the microbiological quality of water prior to consumption (residual disinfection, protected distribution, improved storage). The effects of chemical contaminants (i.e. arsenic, fluoride) are not included in this review.

  • Water quantity or supply is any intervention to provide a new or improved water supply or improved distribution (installation of a new hand pump or household connection), or both.

  • Sanitation is any intervention to introduce or expand the provision or use of facilities for excreta disposal (flush or pour flush to piped sewer system, septic tank or pit latrine; ventilated improved pit (VIP) latrine; pit latrine with slab; or composting toilet).

  • Hygiene is any intervention that promotes adoption of, or increased practice of, handwashing with soap after defecation and disposal of child faeces, prior to preparing and handling food and before eating (group discussions, media campaigns, leaflets, songs, pictorial stories, dramas etc.).

 

How the intervention might work

The conceptual framework linking poor water supply and quality, poor sanitation and hygiene with child nutritional status identifies both direct pathways, namely diarrhoea (Briend 1990; Guerrant 2008), environmental enteropathy (Humphrey 2009) and nematode infections (Pruss-Ustun 2006); and indirect pathways, namely the time taken to collect water at long distances from the home, the purchase of water from water vendors and contamination of groundwater by heavy metals (Figure 1). The direct pathways relate to the body's ability to respond to infection or parasitic infestation and the impact of these assaults on nutritional status and health. Indirect pathways relate more to the ability of families to provide safe and clean living environments and have time to provide adequate care to their children. This review will focus only on the evidence that WASH interventions act through the direct pathways namely, diarrhoea, environmental enteropathy and nematode infections (Figure 2).

 FigureFigure 1. Conceptual framework showing how poor water, sanitation and hygiene might impact child nutritional status, directly and indirectly
 FigureFigure 2. Conceptual framework showing how poor water, sanitation and hygiene might directly impact child nutritional status

 

Why it is important to do this review

Several Cochrane reviews have been published on the impact of WASH interventions on diarrhoea incidence.

Clasen 2006 reviewed the impact of improved water quality on diarrhoea incidence. The review contained 30 trials and 53,000 individuals. Meta-analysis identified that interventions that improve the quality of water reduce diarrhoea incidence for populations of all ages and children under five years. Interventions at the household level were more effective than those implemented at water sources.

Clasen 2010 reviewed the impact of improved disposal of human excreta on diarrhoea incidence. The review included 13 trials and 33,400 individuals. Meta-analysis identified that interventions that improve disposal of human excreta reduce diarrhoea incidence.

Ejemot 2008 reviewed the impact of the promotion of handwashing on diarrhoeal incidence. The review included 14 trials and 7711 individuals. Meta-analyses identified that interventions that promote handwashing reduce diarrhoea incidence.

The association between diarrhoea and other enteric infections and child nutritional outcomes is complex but recent analysis of cohort data suggests that repeated diarrhoea incidence in the first two years of life significantly increases the risks of being stunted by age two years (Checkley 2008; Guerrant 2008; Pruss-Ustun 2006).

Cochrane reviews published to date of the impact of WASH interventions have focused only on diarrhoea incidence, and there are no published reviews of the effect of WASH interventions on child nutritional status. The current review is designed to evaluate the strength of evidence linking WASH interventions with measures of child nutritional status. Potential indirect effects of improved nutritional status (such as school performance and school attendance) are not included in the review. By linking up the distinct WASH and nutrition evidence bases in a Cochrane review, the role of WASH interventions in improving child health and nutrition will be identified and future research priorities can be established.

 

Objectives

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

To evaluate the effect of interventions to improve water quality and supply (adequate quantity to maintain hygiene practices), provide adequate sanitation and promote handwashing with soap, on the nutritional status of children under the age of 18 years and to identify current research gaps.

 

Methods

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Criteria for considering studies for this review

 

Types of studies

Randomised (including cluster-randomised), quasi-randomised and non-randomised controlled trials, controlled before and after studies (cohort or cross-sectional), interrupted time series (ITS) and historically controlled studies.

 

Types of participants

Children aged under 18 years.

 

Types of interventions

 

Intervention

  1. Any intervention aimed at improving the microbiological quality of drinking water, including:
    1. removing or inactivating microbiological pathogens via household, community or water source level water treatment systems (filtration, sedimentation, chemical treatment, heat treatment, UV radiation), or both;
    2. protecting the microbiological quality of water prior to consumption (residual disinfection, protected distribution, improved storage).
  2. Any intervention aimed at introducing a new or improved water supply or improved distribution (installation of a hand pump or household connection), or both.
  3. Interventions aimed at introducing or expanding the coverage and use of facilities designed to improve sanitation, i.e. to reduce direct and indirect contact with human faeces (pour-flush, composting or water sealed flush toilet, piped sewer system, septic tank, simple pit latrines, VIP latrine or use of a potty or scoop for the disposal of child faeces).
  4. Interventions aimed at the promotion of handwashing with soap after defecation, disposal of child faeces and prior to preparing and handling food (group discussions, media campaigns, leaflets, songs, pictorial stories, dramas etc.).
  5. Any combination of the WASH interventions listed above.

 

Control

  1. Water quality: study participants who have continued with usual practice, or a less stringent version of the intervention (i.e. new protected well but no household disinfection on top of this).
  2. Water supply: study participants who have continued with usual practice.
  3. Sanitation: study participants who have continued to practice open defecation or who continue with usual practice regarding excreta disposal rather than following the prescribed intervention.
  4. Hygiene: no handwashing promotion; study participants who continued with usual practice.

There was no minimum duration of intervention.

 

Types of outcome measures

 

Primary outcomes

  • Child nutritional status as measured by anthropometry: weight-for-age (underweight), weight-for-height (wasting), height-for-age (stunting).

 

Secondary outcomes

  • Child nutritional status as measured by anthropometry: weight, height, mid-upper arm circumference, skinfold thickness, percent body fat, birthweight, body mass index (BMI).
  • Child nutritional status as measured by nutrient status: haemoglobin, serum ferritin, soluble transferrin receptor, serum retinol, serum zinc, urinary iodine, clinical signs of nutrient deficiency.

 

Search methods for identification of studies

 

Electronic searches

We searched the following databases using a keyword search and MeSH terms. We adapted search terms according to the requirements or individual databases.

  • Cochrane Public Health Group Special Register
  • MEDLINE (general medicine)
  • MEDLINE In-Process
  • Web of Science (including Science Citation Index Expanded (SCI-EXPANDED) 1970 to present; Social Sciences Citation Index (SSCI) 1970 to present; Conference Proceedings Citation Index-Science (CPCI-S) 1990 to present; Conference Proceedings Citation Index - Social Science & Humanities (CPCI-SSH) 1990 to present)
  • EMBASE (general medicine)
  • Econlit (economics)
  • Global Health (public health)
  • Greenfile (environment)
  • CAB Abstracts (applied life sciences)
  • Trial registers (CENTRAL, metaRegister of Controlled Trials (mRCT))
  • Chinese-language databases available under the China National Knowledge Infrastructure (CNKI-CAJ) (Fung 2008):
    • Chinese Biomedical Literature database (CBM)
    • China National Knowledge Infrastructure (CNKI)
    • VIP information/Chinese Scientific Journals database

We prepared search strategies in English (Appendix 1) and Chinese (Appendix 2). There were no language or date restrictions. We handsearched reference lists of key articles for any additional relevant articles. We contacted subject experts and study authors and asked them to provide additional information and further relevant references.

We performed an initial literature search in July 2011, followed by an update search in June 2012.

 

Searching other resources

We contacted the following researcher groups and organisations for information on unpublished and ongoing trials: Public-Private Partnership for Handwashing with Soap (http://www.globalhandwashing.org/); IRC International Water and Sanitation Centre (http://www.irc.nl/); Department of Child and Adolescent Health and Development (WHO) (http://www.who.int/maternal_child_adolescent/en/); World Bank (http://www.worldbank.org/); World Bank Water and Sanitation Programme (http://water.worldbank.org/related-topics/water-and-sanitation-program); World Health Organization (WHO) (http://www.who.int/en/) and United Nations Children's Fund (UNICEF) (http://www.unicef.org.uk/); International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) (http://www.icddrb.org/); Water, Sanitation and Health Programme (WHO) (http://www.who.int/water_sanitation_health/en/); Environmental Health Project (USAID) (http://www.ehproject.org/); Foodborne and Diarrheal Diseases Branch, Centers for Disease Control and Prevention (CDC) (http://www.cdc.gov/foodborne/about_fddb.htm); USAID (http://www.usaid.gov/) and UK Department for International Development (DFID) (http://www.dfid.gov.uk/).

We also searched the following for relevant abstracts:

  • Waterlines journal;
  • International Water Association and the Water, Engineering and Development Centre (Loughborough University, UK);
  • public health conferences (e.g. American Public Health Association; European Public Health Association).

 

Data collection and analysis

 

Selection of studies

Two authors (LW and SB) reviewed the titles and abstracts retrieved through the English-language search strategy independently in order to identify and select potentially relevant studies using pre-defined inclusion criteria, and the full text of all articles selected by either team member were retrieved for a full-text review. One author (YC) reviewed the results of the Chinese-language search, undertook the same process and summarised the article in English; LW and SB reviewed the summaries to independently determine study eligibility. Where there was a difference of opinion, disagreement was resolved through discussion with a third review author (ADD). All studies which initially appeared to meet the inclusion criteria but upon inspection of the full text did not meet inclusion criteria are detailed in the Characteristics of excluded studies table with reasons for exclusion. We contacted authors of 12 potentially eligible excluded studies (in English and Chinese) that did not report nutrition outcomes and asked them to provide information on the availability of nutrition outcome data. All authors responded, and one author (two studies) provided additional unpublished data (Luby 2004; Luby 2006).

 

Data extraction and management

Two authors (LW and SB) independently extracted data from all relevant articles; LW contacted authors to supply missing data where possible. The data extraction forms were based on the data collection form from the Cochrane Effective Practice and Organisation of Care (EPOC) Group and Cochrane Public Health Group, modified for use in this review. Quality criteria questions for the different study designs were built into this form. Any discrepancies between the two review authors were resolved by a third author (ADD). LW entered the extracted data into Review Manager 5 (RevMan 2012). Multiple papers reporting results from one study were considered as one study. We used a standard approach where comparisons of multiple reports and publications of the same study were checked for contradictions and completeness and the data used once.

 

Assessment of risk of bias in included studies

Two review authors (LW and SB) independently assessed the risk of bias of included studies using the EPOC 'Risk of bias' tool for studies with a separate control group. This tool includes additional items to assess the risk of selection bias and subsequent confounding ("were baseline outcome measurements similar?" and "were baseline characteristics similar?"), as well as an additional item to consider the likelihood of contamination ("was the study adequately protected against contamination?"). We also supplemented the EPOC 'Risk of bias' tool with another additional item to address whether the study authors appropriately adjusted for important confounders in their analysis. We assessed studies for each item with answers of 'Low' indicating low risk of bias, 'High' indicating high risk of bias and 'Unclear' indicating either lack of information or uncertainty over the potential for bias. We contacted study authors for additional information where possible. Any discrepancies were resolved by a third author (ADD).

 

Measures of treatment effect

We present treatment effect sizes for continuous outcomes and report them using their original scale. All measures of effect are presented with 95% confidence intervals (CI).

 

Unit of analysis issues

The unit of analysis was the individual. We adjusted data derived from the five cluster-randomised controlled trials (Du Preez 2010; Du Preez 2011; McGuigan 2011; Luby 2004; Luby 2006) to allow for the clustered design.

 

Dealing with missing data

We contacted authors of included studies requesting missing information and received responses to all our queries. Through this process we were sent data sets including nutrition outcomes in children from three studies (Du Preez 2010; Du Preez 2011; McGuigan 2011), only one of which had previously been reported (Du Preez 2011). We also contacted authors of 12 potentially eligible excluded studies (in English and Chinese) that did not report nutrition outcomes and were sent two further data sets of previously unpublished data (Luby 2004; Luby 2006). Study authors also provided unpublished trial protocols when available.

 

Assessment of heterogeneity

Clinical heterogeneity caused by differences in participant characteristics is likely to be moderate as studies only included poorly nourished children from low- or middle-income countries. We assessed statistical heterogeneity using the I² statistic according to guidance of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011 Sections 9.5 to 9.6).

 

Assessment of reporting biases

Nutritional outcome measures have only rarely been assessed in WASH studies to date and when they are measured they are often classified as secondary outcomes. In our review, we identified four studies in which nutritional status measures had been collected but had not been reported in the published literature. We contacted the principal investigators of these studies and they immediately provided us with full access to these unreported data. Despite a rigorous search, it is possible that other WASH studies have collected nutrition data that have not been reported.

 

Data synthesis

We conducted data synthesis of study outcomes by group (intervention and control) using Review Manager 5. We created forest plots without meta-analysis including all possible studies by outcome to enable visual inspection of the available data. Substantial heterogeneity in the designs of studies included in the review limited the amount of meta-analysis possible. Meta-analysis combining randomised and non-randomised studies is not recommended (Higgins 2011) and formal meta-analysis was therefore restricted to include only the five identified cluster-randomised controlled trials (Du Preez 2010; Du Preez 2011; Luby 2004; Luby 2006; McGuigan 2011). All trials were primarily designed to reduce diarrhoea incidence, and diarrhoea incidence lies on the direct causal pathway between WASH and nutrition outcomes in children. The pooling of different WASH interventions in meta-analysis allowed the combined impact of WASH interventions to be assessed. We summarised the remaining nine studies using a narrative synthesis. Our analysis of the effect of the intervention is reported for each study separately (Effects of interventions).

Study authors provided raw anthropometric data for five cluster-randomised controlled trials (Du Preez 2010; Du Preez 2011; Luby 2004; Luby 2006; McGuigan 2011) from which anthropometric indices (weight-for-age, weight-for-height and height-for-age) were calculated using the WHO Anthro software (available at: http://www.who.int/childgrowth/en/). For these trials, we calculated means and cluster-adjusted standard deviations (SD) in Stata version 12 (http://www.stata.com/stata12/) prior to analysis in Review Manager 5. Study-level meta-analysis included data on 4622 to 4627 children (depending on outcome) who had baseline and final measures in the included cluster-randomised controlled trials.

Three studies included more than one intervention arm (Bowen 2012; Luby 2004; Luby 2006):

Bowen 2012 had two intervention arms: handwashing with soap and handwashing with soap plus treatment of drinking water with flocculent disinfectant. The overall effect of intervention versus control was examined by pooling the individual effect of each of these intervention arms (mean and SD) and weighting the pooled values for the numbers within each arm.

Luby 2004 had two intervention arms: handwashing with antibacterial soap, and handwashing with plain soap. In study-level meta-analysis the overall effect of intervention versus control was examined by pooling the individual effect of each intervention arm (mean and SD) and weighting the pooled values for the numbers within each arm.

Luby 2006 had four intervention arms: handwashing with soap, handwashing with soap plus treatment of drinking water with flocculent disinfectant, treatment of drinking water with bleach and treatment of drinking water with flocculent disinfectant. In study-level meta-analysis we combined the effect of water quality interventions (treatment of drinking water with bleach and treatment of drinking water with flocculent disinfectant), and compared this with promotion of handwashing with soap, promotion of handwashing with soap and treatment of drinking water with flocculent disinfectant, and the control arm. Overall values were weighted for the numbers within each arm. In our analysis, Luby 2006 included three intervention groups (soap, soap plus flocculent disinfectant and flocculent disinfectant and bleach) and for this study the shared group (control) was split into three to provide three reasonably independent comparisons (see Cochrane Handbook for Systematic Reviews of Interventions, Section 16.5.4).

We conducted individual participant data (IPD) analysis in Stata version 12 using the raw data provided from the five cluster-randomised controlled trials only (Du Preez 2010; Du Preez 2011; Luby 2004; Luby 2006; McGuigan 2011). In IPD analysis, we estimated the effect of WASH interventions on weight-for-age, weight-for-height and height-for-age, height and weight using analysis of covariance models (i.e. final follow-up measure adjusted for baseline measure) additionally adjusting for age at baseline, duration of treatment and sex. The analysis used random-effects models to allow for both within-study and within-cluster variability, where cluster is the unit of randomisation in each study. Heterogeneity of treatment effects across trials was tested by including a random slope for the intervention. Children with missing data were removed from the analysis. In IPD analysis we pooled the data from studies with more than one intervention arm to allow comparison of outcome of children in intervention and control arms. IPD meta-analysis included data on 5375 to 5386 children (depending on outcome) who had baseline and at least one follow-up measure in the five included cluster-randomised controlled trials.

We conducted the analyses on an intention-to-treat basis. We collated a 'Summary of findings' table, providing information on primary outcomes, effect sizes and quality of information.

 

Subgroup analysis and investigation of heterogeneity

We conducted pre-specified subgroup analysis by sex and age group (two years and under and two to five years) for those studies eligible for inclusion in meta-analysis. All of the studies in the review were six months or longer in duration, conducted in low- or middle-income countries and conducted in a mixture of rural, peri-urban and urban locations, and only one study included children aged over five years, precluding analysis by other pre-specified subgroups (duration of intervention, country setting, community location, age group over five years).

 

Sensitivity analysis

We planned to carry out a sensitivity analysis on studies judged to be at a low risk of bias. However, no sensitivity analysis was conducted as no included study was judged to be free of bias.

 

Results

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Description of studies

See Characteristics of included studies, Characteristics of ongoing studies and outline of included studies ( Table 1). Luby 2006 is included as three independent comparisons: Luby 2006 (Soap); Luby 2006 (Soap & Floc); Luby 2006 (Floc & Bleach) (see Data synthesis above).

 

Results of the search

The search strategy up to June 2012 identified 20,458 titles and abstracts: 17,492 from the English search, 20 from grey literature searching and author contacts, and 2966 from Chinese literature. After de-duplication and first assessment by two authors, we obtained 71 for further assessment. Following assessment by two authors, 54 were discarded. Fourteen studies (described in 17 reports) met the inclusion criteria. Of the 17 included reports, 15 were published in journals, one was a UNDP/World Bank report and one was a book chapter. All of the included studies were published in English. The study selection process is outlined in Figure 3.

 FigureFigure 3. Study flow diagram.

In addition, five ongoing studies were identified through contact with experts (Characteristics of ongoing studies).

 

Included studies

 

Study characteristics

All included studies were conducted in low-income or middle-income country settings. Three studies were conducted in Pakistan (Bowen 2012; Luby 2004; Luby 2006), two studies in Bangladesh (Ahmed 1993; Hasan 1989), two in Guatemala (Arnold 2009; Guzman 1968), one in Kenya (Du Preez 2011), one in Ethiopia (Fenn 2012), one in Nigeria (Huttly 1990), one in Nepal (Langford 2011), one in Cambodia (McGuigan 2011), one in South Africa (Du Preez 2010) and one in Chile (Schlesinger 1983). Seven studies were in rural settings (Ahmed 1993; Arnold 2009; Fenn 2012; Guzman 1968; Hasan 1989; Huttly 1990; McGuigan 2011), six in urban settings (Bowen 2012; Du Preez 2010; Langford 2011; Luby 2004; Luby 2006; Schlesinger 1983) and one in both rural and urban settings (Du Preez 2011).

Five studies were cluster-randomised controlled trials (Du Preez 2010; Du Preez 2011; Luby 2004; Luby 2006; McGuigan 2011), one study was a follow-up study of a cluster-randomised controlled trial (Bowen 2012), three studies were longitudinal studies with control groups (Guzman 1968; Langford 2011; Schlesinger 1983), three studies were repeated cross-sectional studies with control groups (Ahmed 1993; Hasan 1989; Huttly 1990), one study was a controlled before and after study (Fenn 2012) and one was a cross-sectional study with a matched historical control group (Arnold 2009).

Study duration ranged from 6 to 60 months. Two interventions were implemented for six months (Ahmed 1993; Langford 2011), two interventions for nine months (Bowen 2012; Luby 2006), four interventions for 12 months (Du Preez 2010; Du Preez 2011; Luby 2004; McGuigan 2011), one intervention for 20 months (Schlesinger 1983), one intervention for 30 months (Huttly 1990), one intervention for 36 months (Arnold 2009), one intervention for 48 months (Hasan 1989) and one intervention for 60 months (Guzman 1968).

Anthropometric measures were reported in 10 studies (Ahmed 1993; Bowen 2012; Arnold 2009; Du Preez 2011; Fenn 2012; Guzman 1968; Hasan 1989; Huttly 1990; Langford 2011; Schlesinger 1983). Four studies did not report anthropometric measures (Du Preez 2010; Luby 2004; Luby 2006; McGuigan 2011), but study authors provided raw anthropometric data collected in these studies on request. One study additionally reported blood haemoglobin concentration (Bowen 2012) (a biochemical measure of iron nutriture). In addition to nutritional status, other outcomes reported included episodes of diarrhoea, acute respiratory infections, other infections, knowledge, attitudes and practice of hygiene practices, and self-reported water, sanitation and hygiene practices. Nutritional status was reported as an outcome of secondary importance in all of the studies and none of the studies reported differential impacts relevant to equity issues such as gender, socioeconomic status and religion.

 

Participants

All studies included children aged under five years, although one study (Bowen 2012) that followed up participants three years after the end of a cluster-randomised trial included children who were up to eight years old. Interventions were directed to households that contained young children and outcomes of interest were assessed in children only. The number of children for whom nutrition outcome data were available ranged between studies from 88 (Langford 2011) to 2115 (Luby 2006) and in total 22,241 children were included at baseline.

 

Interventions

Details of the WASH interventions implemented in the included studies are provided in  Table 1. Three studies (Du Preez 2010; Du Preez 2011; McGuigan 2011) reported interventions to improve the quality of water, one study (Guzman 1968) reported a sanitation intervention, three studies (Ahmed 1993; Langford 2011; Luby 2004) reported interventions to improve hygiene, three studies (Arnold 2009; Bowen 2012; Luby 2006) reported a dual water quality and hygiene intervention, one study (Schlesinger 1983) reported a dual intervention on water quantity and sanitation, one study (Huttly 1990) reported an intervention including water quality, quantity and hygiene, one study (Fenn 2012) reported an intervention including water quantity, sanitation and hygiene elements, and one study (Hasan 1989) included all four WASH elements (water quality, quantity, sanitation and hygiene).

Process and implementation data were poorly reported in the included studies. Targeting and coverage was reported in four studies. Ahmed 1993 reported that 98% of the intervention group were targeted with the hygiene programme in Bangladesh. Arnold 2009 reported that "the majority" of intervention households were targeted by the intervention in Guatemala. Hasan 1989 reported 90% coverage of latrines and hygiene interventions in Bangladesh. Huttly 1990 reported 96% coverage of boreholes in Nigeria. Adherence to intervention was reported in two studies. Du Preez 2010 reported less than 35% adherence to a solar disinfection (SODIS) intervention in South Africa, and McGuigan 2011 reported more than 90% adherence to a SODIS in Cambodia. Study attrition was assessed for seven studies (Bowen 2012; Du Preez 2010; Du Preez 2011; Langford 2011; Luby 2004; Luby 2006; McGuigan 2011) and ranged from 16.5% (Bowen 2012) to 4% (Du Preez 2011). The designs of the other seven studies precluded assessment of attrition.

Intervention cost was reported in one study in Bangladesh (Hasan 1989). The cost for the installation of hand pumps in Bangladesh was USD 6.89/inhabitant, for latrines was USD 4.67/inhabitant and for the hygiene education USD 3.60/inhabitant. The total cost of WASH interventions was USD 15/inhabitant.

 

Excluded studies

See Characteristics of excluded studies. Fifty-three studies were excluded for the following reasons: incorrect study design (24 studies), no nutritional outcome (11 studies), no control group (seven studies), reporting of baseline information only (four studies) and use of an intervention not included in this review (six studies).

 

Risk of bias in included studies

We assessed risk of bias at outcome level for each study. For detailed information on the risk of bias of individual studies see the 'Risk of bias' tables for each study and the 'Risk of bias' summary (Figure 4). None of the included studies was considered to be at low risk of bias. 

 FigureFigure 4. 'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.

 

Allocation

We judged sequence generation to be adequate (by coin flipping and random number generation) in seven studies (Bowen 2012; Du Preez 2010; Du Preez 2011; Langford 2011; Luby 2004; Luby 2006; McGuigan 2011). None of the studies were considered at low risk of bias for allocation concealment.

 

Blinding

Participants were not masked from the intervention in any of the studies, and we judged all studies to be at high risk of performance bias. Insufficient information was provided to make judgements about detection bias in any of the studies and we graded all studies as unclear.

 

Incomplete outcome data

The designs of several of the studies, such as repeat cross-sectional studies and the cross-sectional study with the matched historical control group, precluded assessment of attrition bias. We judged eight studies to be of low risk of attrition bias (Bowen 2012; Du Preez 2010; Du Preez 2011; Langford 2011; Luby 2004; Luby 2006; McGuigan 2011; Schlesinger 1983).

 

Selective reporting

We assessed the trial registries and protocols (where available) of the five cluster-randomised controlled trials; we were not able to identify study protocols for the nine other studies. The trial registries or protocols of four cluster-randomised controlled trials (Du Preez 2010; McGuigan 2011; Luby 2004; Luby 2006) stated that they would collect child nutritional status information and did not report these data in the primary research publications.

 

Other potential sources of bias

There were no other potential sources of bias identified.

 

Effects of interventions

See:  Summary of findings for the main comparison

Ahmed 1993 was a repeat cross-sectional study among 370 households in Bangladesh. Compared to children in the control households, a hygiene promotion intervention significantly reduced the percentage of very underweight children (weight-for-age < -3 z-scores) under the age of 24 months.

Arnold 2009 was a cross-sectional study with a matched historical control group among 877 children under five years of age in Guatemala. Compared to children in the historical control, a water quality and handwashing intervention had no effect on weight-for-age z-score (mean difference (MD) -0.06; 95% confidence interval (CI) -0.23 to 0.11), weight-for-height z-score (MD -0.07; 95% CI -0.28 to 0.14), height-for-age z-score (MD 0.04; 95% CI -0.19 to 0.27) or mid-upper arm circumference (cm) (MD -0.01; 95% CI -0.17 to 0.15).

Bowen 2012 was a follow-up study conducted three years after the end of a cluster-randomised controlled trial among 461 children under five years of age in Pakistan. At the time of follow-up assessment children were eight years old. Compared to children in the control clusters, a water quality and hygiene intervention had no effect on weight-for-age z-score (MD -0.06; 95% CI -0.27 to 0.15), height-for-age z-score (MD 0.08; 95% CI -0.29 to 0.27) or body mass index (BMI)-for-age z-score (MD 0.02; 95% CI -0.18 to 0.22).

Du Preez 2010 was a cluster-randomised controlled trial among 824 children under five years of age in South Africa. Relevant nutrition outcome data were available for 332 children. Compared to children in the control arm, a water quality (SODIS) intervention had no effect on weight-for-age z-score (MD 0.21; 95% CI -0.07 to 0.49), weight-for-height z-score (MD 0.08; 95% CI -0.20 to 0.36) or height-for-age z-score (MD 0.28; 95% CI -0.06 to 0.62).

Du Preez 2011 was a cluster-randomised controlled trial among 1089 children under five years of age in Kenya. Relevant nutrition outcome data were available for 525 children. Compared to children in the control arm, a water quality (SODIS) intervention had no effect on weight-for-age z-score (MD -0.01; 95% CI -0.23 to 0.21), weight-for-height z-score (MD -0.11; 95% CI -0.30 to 0.08) or height-for-age z-score (MD 0.11; 95% CI -0.19 to 0.41).

Fenn 2012 was a controlled before and after study among 2476 children under three years of age in Ethiopia. Compared to the children in the control areas, a water quantity, sanitation and hygiene intervention significantly improved height-for-age z-score (MD 0.22; 95% CI 0.11 to 0.33).

Guzman 1968 was a longitudinal study among 312 children under five years of age in Guatemala. Height and weight of the children were measured during a sanitation intervention but no effects were reported.

Hasan 1989 was a repeat cross-sectional study among 405 children under three years of age in Bangladesh. Compared to the children in the control areas, a sanitation, water quantity, water quality and hygiene promotion intervention had no significant effect on weight-for-age, weight-for-height and height-for-age z-scores.

Huttly 1990 was a repeat cross-sectional study among 632 children under three years of age in Nigeria. In villages that received a water quantity, quality and hygiene education intervention, the percentage of children who were thin (< 80% of the median weight-for-height) declined significantly. No such decline was detected among children in the control villages.

Langford 2011 was a longitudinal study among 88 children under one year of age in Nepal. Compared to children in the control areas, a handwashing intervention had no effect on weight-for-age z-score (MD -0.24; 95% CI -0.76 to 0.28), weight-for-height z-score (MD -0.11; 95% CI -0.53 to 0.31) or height-for-age z-score (MD -0.13; 95% CI -0.54 to 0.28).

Luby 2004 was a cluster-randomised controlled trial among 4961 children under five years of age in Pakistan. Relevant nutrition outcome data were available for 873 children. Compared to children in the control arm, a handwashing intervention had no effect on weight-for-age z-score (MD 0.01; 95% CI -0.10 to 0.12), weight-for-height z-score (MD 0.03; 95% CI -0.32 to 0.38) or height-for-age z-score (MD -0.01; 95% CI -0.37 to 0.35).

Luby 2006 (Soap) was a cluster-randomised controlled trial among 8949 children under five years of age in Pakistan. For this intervention arm, relevant nutrition outcome data were available for 533 children. Compared to children in the control arm, a handwashing intervention had no effect on weight-for-age z-score (MD 0.05; 95% CI -0.13 to 0.23), weight-for-height z-score (MD 0.02; 95% CI -0.20 to 0.24) or height-for-age z-score (MD 0.08; 95% CI -0.13 to 0.29).

Luby 2006 (Soap & Floc) was a cluster-randomised controlled trial among 8949 children under five years of age in Pakistan. For this intervention arm, relevant nutrition outcome data were available for 549 children. Compared to children in the control arm, a handwashing and water quality intervention had no effect on weight-for-age z-score (MD 0.07; 95% CI-0.11 to 0.25), weight-for-height z-score (MD 0.06; 95% CI -0.16 to 0.28) or height-for-age z-score (MD 0.06; 95% CI -0.12 to 0.24).

Luby 2006 (Floc & Bleach) was a cluster-randomised controlled trial among 8949 children under five years of age in Pakistan. For this intervention arm, relevant nutrition outcome data were available for 1055 children. Compared to children in the control arm, a water quality intervention had no effect on weight-for-age z-score (MD 0.03; 95% CI -0.12 to 0.18), weight-for-height z-score (MD 0.02; 95% CI -0.20 to 0.24) or height-for-age z-score (MD 0.04; 95% CI -0.08 to 0.16).

McGuigan 2011 was a cluster-randomised controlled trial among 928 children under five years of age in Cambodia. Relevant nutrition outcome data were available for 760 children. Compared to children in the control arm, a water quality (SODIS) intervention had no effect on weight-for-age z-score (MD 0.26; 95% CI -0.01 to 0.53), weight-for-height z-score (MD 0.15; 95% CI -0.15 to 0.45) or height-for-age z-score (MD 0.22; 95% CI -0.04 to 0.48).

Schlesinger 1983 was a longitudinal study among 209 children under four years of age in Chile. In households that received a sanitation and water supply intervention, the percentage of underweight children (defined as a deficit for age of 10% or more below the 50th percentile of National Center for Health Statistics (NCHS) reference) did not change, while in control households the percentage of underweight children increased significantly.

The 'Summary of findings' table ( Summary of findings for the main comparison) lists the results of those randomised and non-randomised studies that reported primary review outcomes, with the pooled estimate. Descriptive forest plots include a maximum of nine studies (four non-randomised and five randomised studies) on the following primary review outcomes: weight-for-age z-score, weight-for-height z-score and height-for-age z-score, and on the following secondary review outcomes: weight and height. Studies not included in descriptive forest plots tended to be older and either did not report outcomes in a metric appropriate for the review (Ahmed 1993; Guzman 1968; Huttly 1990; Schlesinger 1983) or incompletely reported relevant outcomes (Hasan 1989). Of the five studies not included in the forest plots, three reported a significant benefit of water, sanitation and hygiene (WASH) interventions on measures of weight in children (Ahmed 1993; Huttly 1990; Schlesinger 1983), one reported no effect (Hasan 1989) and one did not report an outcome (Guzman 1968).

 

Weight-for-age z-score

Weight-for-age z-score data were reported in three non-randomised studies and available for five cluster-randomised controlled trials (Figure 5). No effect on weight-for-age z-score was reported in the three non-randomised studies (Arnold 2009; Bowen 2012; Langford 2011). Meta-analysis conducted only on data from the five cluster-randomised controlled trials (Du Preez 2010; Du Preez 2011; Luby 2004; Luby 2006 (Floc & Bleach); Luby 2006 (Soap); Luby 2006 (Soap & Floc); McGuigan 2011) including 4627 children aged under five years ( Analysis 1.2; Figure 6) identified no evidence of an effect of WASH interventions on weight-for-age z-score (MD 0.05; 95% CI -0.01 to 0.12). There was no evidence of between-study heterogeneity (I² = 0%). Individual participant data (IPD) meta-analysis including 5386 children identified no evidence of an effect of WASH on weight-for-age z-score (MD 0.10 z-score; 95% CI -0.04 to 0.25).

 FigureFigure 5. Forest plot of comparison: Weight-for-age (all studies)
 FigureFigure 6. Forest plot of comparison: Weight-for-age (RCTs only)

 

Weight-for-height z-score

Weight-for-height z-score data were reported in two non-randomised studies and available for five cluster-randomised controlled trials (Figure 7). No effect on weight-for-height z-score was reported in the two non-randomised studies (Arnold 2009; Langford 2011). Meta-analysis conducted only on data from the five cluster-randomised controlled trials (Du Preez 2010; Du Preez 2011; Luby 2004; Luby 2006 (Floc & Bleach); Luby 2006 (Soap); Luby 2006 (Soap & Floc); McGuigan 2011) including 4622 children aged under five years ( Analysis 2.2; Figure 8) identified no evidence of an effect of WASH interventions on weight-for-height z-score (MD 0.02; 95% CI -0.07 to 0.11). There was no evidence of between-study heterogeneity (I² = 0%). IPD meta-analysis including 5375 children identified no evidence of an effect of WASH on weight-for-height z-score (MD 0.10 z-score; 95% CI -0.09 to 0.23).

 FigureFigure 7. Forest plot of comparison: Weight-for-height (all studies)
 FigureFigure 8. Forest plot of comparison: Weight-for-height (RCTs only)

 

Height-for-age z-score

Height-for-age z-score data were reported in four non-randomised studies and available for five cluster-randomised controlled trials (Figure 9). No effect on height-for-age z-score was reported in three of the non-randomised studies (Arnold 2009; Bowen 2012; Langford 2011), an increase in height-for-age z-score (MD 0.22; 95% CI 0.11 to 0.33) was reported by Fenn 2012. Meta-analysis conducted only on data from the five cluster-randomised controlled trials (Du Preez 2010; Du Preez 2011; Luby 2004; Luby 2006 (Floc & Bleach); Luby 2006 (Soap); Luby 2006 (Soap & Floc); McGuigan 2011) including 4627 children aged under five years ( Analysis 3.2; Figure 10) identified a borderline statistically significant effect of WASH interventions on height-for-age z-score (MD 0.08; 95% CI 0.00 to 0.16). There was no evidence of between-study heterogeneity (I² = 0%). IPD meta-analysis including 5386 children identified a statistically significant effect of WASH on height-for-age z-score (MD 0.11 z-score; 95% CI 0.03 to 0.18).

 FigureFigure 9. Forest plot of comparison: Height-for-age (all studies)
 FigureFigure 10. Forest plot of comparison: Height-for-age (RCTs only)

 

Subgroup analysis

Subgroup analyses carried out using the aggregated data suggest that there is no effect of age group (two years and under; two to five years) on weight-for-age and weight-for-height, and no evidence of an effect of gender on weight-for-height.

Subgroup analyses suggest no evidence of an effect on weight-for-age for boys (MD 0.00; 95% CI -0.07 to 0.08), but demonstrated some evidence of an effect for girls (weight-for-age MD 0.11; 95% CI 0.01 to 0.21) ( Analysis 1.3; Figure 11). Similarly, subgroup analyses suggest no evidence of an effect on height-for-age for boys (MD -0.01; 95% CI -0.09 to 0.08), but demonstrated some evidence of an effect for girls (height-for-age MD 0.14; 95% CI 0.04 to 0.25) ( Analysis 3.3; Figure 12).

 FigureFigure 11. Forest plot of comparison: 1 Weight-for-age, outcome: 1.3 Weight-for-age (gender).
 FigureFigure 12. Forest plot of comparison: 3 Height-for-age, outcome: 3.3 Height-for-age (gender).

Subgroup analyses identified no evidence of an effect on height-for-age for children aged two years and under years (MD 0.05; 95% CI -0.13 to 0.22), but demonstrated some evidence of an effect for children aged over two years (height-for-age MD 0.06; 95% CI 0.00 to 0.12) ( Analysis 3.4; Figure 13).

 FigureFigure 13. Forest plot of comparison: 3 Height-for-age, outcome: 3.4 Height-for-age (age group).

These apparent differences identified by aggregated analysis are not supported by the IPD analysis. Formal interaction tests between WASH interventions and gender were not significant at the 5% level for either weight-for-age or height-for-age. IPD analysis did, however, find a significant interaction between WASH interventions and gender for weight-for-height (P = 0.032), suggesting that the intervention may be more effective for girls even though the results from the corresponding stratified analyses were not statistically significant.

IPD analysis among 5386 children identified significant interactions between age group and treatment for weight-for-age (P = 0.002), suggesting that the intervention may have a greater effect on weight gain for those children aged over two years (MD two years and under: 0.01; 95% CI -0.15 to 0.16; MD over two years: 0.14, 95% CI -0.01 to 0.28).

Significant interactions were identified between age group and treatment for weight-for-height (P < 0.001), suggesting that the intervention may have a greater effect on weight gain for those children aged over two years (MD two years and under: -0.13, 95% CI -0.31 to 0.05; MD over two years: 0.17, 95% CI 0.01 to 0.34).

Significant interactions were also identified between age group and height-for-age (P < 0.001), suggesting that the intervention may have a greater effect on height growth in children aged two years and under (MD two years and under: 0.25, 95% CI 0.14 to 0.35; MD over two years: 0.03, 95% CI -0.05 to 0.12).

The differences in the findings between the two approaches to the subgroup analysis are unsurprising given the difference in the numbers included. In addition, the IPD analysis looks at the change in the outcome from baseline and adjusts for other factors. The confidence intervals presented in the IPD stratified analyses are estimated directly from the model with the interaction term included.

Analysis by other pre-specified subgroups was precluded as all of the studies in the review were six months or longer in duration, conducted in low- or middle-income countries, conducted in a mixture of rural, peri-urban and urban locations, and only one study included children aged over five years.

 

Other reported nutritional outcomes

Weight was reported in three non-randomised studies and available for five cluster-randomised controlled trials (Figure 14). Meta-analysis conducted only on data from the five cluster-randomised controlled trials including 4627 children aged under five years ( Analysis 4.2; Figure 15) identified no evidence of an effect of WASH interventions on weight (kg) (MD 0.12; 95% CI -0.03 to 0.27). There was no evidence of between-study heterogeneity (I² = 0%). IPD meta-analysis identified no statistically significant effect of WASH on weight (kg) (MD 0.23; 95% CI -0.02 to 0.49).

 FigureFigure 14. Forest plot of comparison: Weight (all studies)
 FigureFigure 15. Forest plot of comparison: Weight (RCTs only)

Height was reported in three non-randomised studies and available for five cluster-randomised controlled trials (Figure 16). Meta-analysis conducted only on data from the five cluster-randomised controlled trials including 4627 children aged under five years ( Analysis 5.2; Figure 17) identified no evidence of an effect of WASH interventions on height (cm) (MD 0.50; 95% CI -0.10 to 1.10). There was no evidence of between-study heterogeneity (I² = 0%). IPD meta-analysis identified a statistically significant effect of WASH on height (cm) (MD 0.53; 95% CI 0.20 to 0.86).

 FigureFigure 16. Forest plot of comparison: Height (all studies)
 FigureFigure 17. Forest plot of comparison: Height (RCTs only)

Mid-upper arm circumference was reported for 877 children under five years in one non-randomised study (Arnold 2009). There is no evidence of an effect of WASH interventions on mid-upper arm circumference (cm) (MD -0.01; 95% CI -0.17 to 0.15). BMI was reported for 461 children under eight years in a follow-up evaluation of a cluster-randomised controlled trial (Bowen 2012). There is no evidence of an effect of WASH interventions on BMI (kg/m2) (mean difference 0.02; 95% CI -0.18 to 0.22). Blood haemoglobin concentration was reported for 461 children under eight years of age in a follow-up evaluation of a cluster-randomised controlled trial (Bowen 2012). The haemoglobin concentration of those of children in the control arm was significantly higher than those among children in the two intervention arms.

 

Discussion

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Summary of main results

Fourteen studies involving a total of 22,241 children at baseline, and nutrition outcome data for 9,469 children, are included in this review. The review included five cluster-randomised controlled trials, one three-year follow-up of a cluster-randomised controlled trial and eight non-randomised studies with comparison groups. Studies included various water, sanitation and hygiene (WASH) interventions either singly or in combination that aimed to improve the quality and quantity of water, and improve sanitation and hygiene. We assessed none of the studies included in the review to be at low risk of bias; several studies had multiple potential risks of bias, and all of the studies failed to mask the WASH intervention from participants. The primary review outcomes weight-for-age, weight-for-height and height-for age were available from nine studies. Study-level and individual participant data (IPD) meta-analysis was limited to data from five cluster-randomised controlled trials that had durations of 9 to 12 months. In this meta-analysis of data from cluster-randomised controlled trials, WASH interventions (specifically solar disinfection of water, provision of soap, and improvement of water quality) were shown to slightly but significantly improve height-for-age z-scores in children under 5 years of age. In subgroup analysis of data from cluster-randomised controlled trials there was some evidence to suggest a difference in effect by gender and age group, with girls more responsive than boys in weight and height growth to WASH interventions, height growth more responsive to WASH interventions in children under 24 months of age, and weight growth more responsive to WASH interventions in children 25-60 months of age.

 

Overall completeness and applicability of evidence

There is suggestive evidence from cluster-randomised controlled trials of a small benefit of WASH interventions on measures of growth in childhood. The evidence from the five cluster-randomised controlled trials included in meta-analysis relates to water quality (SODIS and disinfection by bleach and flocculent disinfectant), hygiene (handwashing with soap), and an intervention including a combination of water quality (flocculent disinfectant) and hygiene (handwashing with soap). Three of the cluster-randomised controlled trials tested solar disinfection of drinking water and the findings of these trials have generated research interest (Arnold 2012; Hunter 2012). There is no evidence of the effect of other WASH interventions on nutritional outcomes in children and a major gap in the literature concerns the effect of water supply and sanitation interventions on nutrition outcomes. Non-randomised studies provided mixed evidence on the effect of a variety of WASH interventions on nutrition outcomes. All interventions were conducted in children under the age of five years and there is no evidence of the effect of WASH interventions in children older than five years of age. All studies were conducted in low- or middle-income countries and there is no evidence of the effect of WASH interventions on children living in high-income countries. Few studies reported process and implementation data. Adherence to study interventions was reported in only two studies (Du Preez 2010; McGuigan 2011) (both cluster-randomised controlled trials) and ranged from low (< 35%) to high (> 90%); both of these studies had a follow-up time of 12 months. Study attrition was assessed in seven studies, ranging from 4% (Du Preez 2011) to 16.5% (Bowen 2012). The five cluster-randomised controlled trials included in meta-analysis were of relatively short duration (9 to 12 months) and there is no evidence available on longer-term impact or adherence to WASH interventions.

Further studies designed to measure the impact of WASH interventions on nutritional status outcomes in children are needed. The first 1000 days of life (from conception to age two years) are thought to be critical in determining growth performance in children. Future studies of the effect of WASH on nutritional status in children may benefit from a focus on early childhood growth from birth to age two years.

 

Quality of the evidence

The review contained reports of the effect of WASH interventions evaluated using a variety of study designs including five cluster-randomised controlled trials. We assessed none of the studies to have high methodological quality. Overall the quality of the evidence is low and further research is likely to have an important impact on confidence in the estimate and is likely to change the estimate of the effect. There are five large randomised controlled trials underway which may help improve the quality of the available evidence.

 

Potential biases in the review process

Every effort was made to conduct this review to the highest standards recommended in the Cochrane Handbook for Systematic Reviews of Interventions and The Cochrane Collaboration's Methodological Expectations of Cochrane Intervention Reviews criteria. Protocols were not available for most of the studies included in the review and it was therefore not possible fully to assess any potential biasses in reporting. However, during the process of the review four studies were identified that collected but did not report nutritional outcomes in children. It is possible that other studies, which we did not identify, collected data on child nutritional status that we have been unable to include in this review.

 

Agreements and disagreements with other studies or reviews

This is the first review looking at the impact of WASH interventions on child nutritional status.

 

Authors' conclusions

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

 

Implications for practice

This review provides evidence that some water, sanitation and hygiene (WASH) interventions (specifically solar disinfection of water, provision of soap, and improvement of water quality) may slightly improve height growth in children under five years of age. The quality of the evidence is generally poor and the overall estimates presented are based only on meta-analyses of data from interventions of relatively short-duration (9-12 months) from only a small selection of possible WASH interventions. These estimates are therefore not applicable to the effect that wider WASH interventions may have on child nutritional status.

 
Implications for research

This review has identified the paucity of rigorous evidence evaluating the effect of WASH interventions on child nutritional status. Several high-quality trials are currently ongoing, the results of which will contribute significantly to the existing evidence base linking WASH interventions to child nutritional status outcomes.

Further research questions relate to the mechanism of action of the WASH interventions. There is no evidence on long-term adherence to WASH interventions, the optimal timing of interventions in childhood or the required duration of interventions to have the greatest impact on childhood nutrition outcomes.

 

Acknowledgements

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

The authors would like to thank the review advisory team, Rebecca Stotzfus and Annette Prüss-Üstün.

This research was made possible with UK aid from the Department of International Development (DFID) as part of the SHARE research programme (www.SHAREresearch.org). The views expressed do not necessarily reflect the Department's official policies.

 

Data and analyses

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
Download statistical data

 
Comparison 1. Weight-for-age

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Weight-for-age (all studies)10Mean Difference (IV, Fixed, 95% CI)Totals not selected

    1.1 Non-randomised studies
3Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    1.2 Randomised studies
7Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 2 Weight-for-age (RCTs only)74627Mean Difference (IV, Random, 95% CI)0.05 [-0.01, 0.12]

 3 Weight-for-age (gender)7Mean Difference (IV, Random, 95% CI)Subtotals only

    3.1 Boys
72344Mean Difference (IV, Random, 95% CI)0.00 [-0.07, 0.08]

    3.2 Girls
72283Mean Difference (IV, Random, 95% CI)0.11 [0.01, 0.21]

 4 Weight-for-age (age group)7Mean Difference (IV, Random, 95% CI)Subtotals only

    4.1 <= 2 years
71464Mean Difference (IV, Random, 95% CI)0.07 [-0.11, 0.24]

    4.2 > 2 years
73163Mean Difference (IV, Random, 95% CI)0.03 [-0.01, 0.06]

 
Comparison 2. Weight-for-height

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Weight-for-height (all studies)9Mean Difference (IV, Fixed, 95% CI)Totals not selected

    1.1 Non-randomised studies
2Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    1.2 Randomised studies
7Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 2 Weight-for-height (RCTs only)74622Mean Difference (IV, Random, 95% CI)0.02 [-0.07, 0.11]

 3 Weight-for-height (gender)7Mean Difference (IV, Random, 95% CI)Subtotals only

    3.1 Boys
72343Mean Difference (IV, Random, 95% CI)-0.02 [-0.12, 0.08]

    3.2 Girls
72279Mean Difference (IV, Random, 95% CI)0.04 [-0.08, 0.15]

 4 Weight-for-height (age group)7Mean Difference (IV, Random, 95% CI)Subtotals only

    4.1 <= 2 years
71464Mean Difference (IV, Random, 95% CI)0.05 [-0.17, 0.27]

    4.2 > 2 years
73158Mean Difference (IV, Random, 95% CI)-0.01 [-0.07, 0.05]

 
Comparison 3. Height-for-age

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Height-for-age (all studies)11Mean Difference (IV, Fixed, 95% CI)Totals not selected

    1.1 Non-randomised studies
4Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    1.2 Randomised studies
7Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 2 Height-for-age (RCTs only)74627Mean Difference (IV, Random, 95% CI)0.08 [0.00, 0.16]

 3 Height-for-age (gender)7Mean Difference (IV, Random, 95% CI)Subtotals only

    3.1 Boys
72344Mean Difference (IV, Random, 95% CI)0.01 [-0.08, 0.11]

    3.2 Girls
72283Mean Difference (IV, Random, 95% CI)0.15 [0.04, 0.26]

 4 Height-for-age (age group)7Mean Difference (IV, Random, 95% CI)Subtotals only

    4.1 <=2 years
71464Mean Difference (IV, Random, 95% CI)0.05 [-0.13, 0.22]

    4.2 > 2 years
73163Mean Difference (IV, Random, 95% CI)0.06 [0.00, 0.12]

 
Comparison 4. Weight

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Weight (all studies)10Mean Difference (IV, Fixed, 95% CI)Totals not selected

    1.1 Non-randomised studies
3Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    1.2 Randomised studies
7Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 2 Weight (RCTs only)74627Mean Difference (IV, Random, 95% CI)0.12 [-0.03, 0.27]

 
Comparison 5. Height

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Height (all studies)10Mean Difference (IV, Fixed, 95% CI)Totals not selected

    1.1 Non-randomised studies
3Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    1.2 Randomised studies
7Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 2 Height (RCTs only)74627Mean Difference (IV, Random, 95% CI)0.50 [-0.10, 1.10]

 

Appendices

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Appendix 1. English search strategy

Dates of coverage: no limit to June 2012

 

Database: Ovid MEDLINE, EMBASE, Global Health and CAB Abstracts

/ - subject heading

* - truncation term

ab - abstract

adj - adjacent to

ti - title

? - optional wildcard term

1. Stunt*.ab,ti.
2. Short stature.ab,ti.
3. Growth.ab,ti.
4. Wast*.ab,ti.
5. Thin.ab,ti.
6. Emaciated.ab,ti.
7. Undernourish*.ab,ti.
8. (BMI or body mass index).ab,ti.
9. (Intra-uterine growth retardation or IUGR).ab,ti.
10. Underweight.ab,ti.
11. Weight-for-age.ab,ti.
12. Height-for-age.ab,ti.
13. Length-for-age.ab,ti.
14. Weight-for-height.ab,ti.
15. ((Increas* or improv* or chang*) adj3 height).ab,ti.
16. ((Increas* or improv* or chang*) adj3 weight).ab,ti.
17. Body fat percentage.ab,ti.
18. Development*.ab,ti.
19. Under?nutrition.ab,ti.
20. Malnutrition.ab,ti.
21. Nutritional status.ab,ti.
22. Nutriti*.ab,ti.
23. (GAM or global acute malnutrition).ab,ti.
24. (SAM or severe acute malnutrition).ab,ti.
25. (PEM or Protein energy malnutrition).ab,ti.
26. Nutritional deficiency status.ab,ti.
27. (An?emia or iron deficiency an?emia).ab,ti.
28. Vitamin a deficienc*.ab,ti.
29. Zinc deficienc*.ab,ti.
30. Iodine deficienc*.ab,ti.
31. (MUAC or mid-upper arm circumference).ab,ti.
32. Skinfold thickness.ab,ti.
33. Anthropometry*.ab,ti.
34. Nutrition Disorders/
35. Child Nutrition Disorders/
36. Infant Nutrition Disorders/
37. Malnutrition/
38. Starvation/
39. Wasting Syndrome/
40. or/1-39 (Combines outcome terms)

41. Child*.ab,ti.
42. Infan*.ab,ti.
43. Baby.ab,ti.
44. Toddler.ab,ti.
45. Pre?school*.ab,ti.
46. young person.ab,ti.
47. (Boy or girl).ab,ti.
48. Child/
49. Child, Preschool/
50. Infant/
51. Adolescent/
52. or/41-51 (Combines Child terms)

53. (Hand$1 adj3 (wash* or clean* or disinfect*)).ab,ti.
54. Hand hygiene.ab,ti.
55. Hand sterility.ab,ti.
56. Handwashing.ab,ti.
57. (water adj3 (improv$ or sediment$ or radiat$ or irradiat$ or UV)).ti,ab.
58. Sanita*.ab,ti.
59. (Latrine$1 or toilet$1 or water closet$1 or privy or pour flush or sewer system$1 or septic tank$1).ab,ti.
60. ((Faeces or feces or fecal or faecal or defecation or excrement or waste or excreta) adj3 (dispos* or manag* or service*)).ab,ti.
61. Water purification.ab,ti.
62. Water microbiology.ab,ti.
63. (Water adj5 (disinfect* or connect* or quality or handpump$1 or standpipe$1 or piped)).ti,ab.
64. (water adj5 (Purif* or treat* or improv* or decontaminat* or filt* or consum* or supply or drink* or quantity or distribut* or stor* or volume)).ab,ti.
65. (water adj3 (safe or improv* or Clean*)).ab,ti.
66. (water adj3 Hygien*).ab,ti.
67. Water Supply/ or Water Purification/ or Water Pollution/ or Sanitation/
68. or/53-67 (Combines water quality interventions)

69. 40 and 52 and 68 (All concepts combined)

 

Database: MEDLINE In-Process

* - truncation term

$ - adjacent to

? - optional wildcard term

1. stunt*
2. short stature
3. growth
4. wast*
5. thin
6. emaciated
7. undernourish*
8. BMI
9. body mass index
10. intra-uterine growth retardation
11. IUGR
12. underweight
13. weight-for-age
14. height-for-age
15. length-for-age
16. weight-for-height
17. Increas* height OR improv* height OR chang* height
18. Increas* weight OR improv* weight OR chang* weight
19. body fat percentage
20. development*
21. under?nutrition
22. malnutrition
23. nutritional status
24. nutrition*
25. GAM OR global acute malnutrition
26. SAM OR severe acute malnutrition
27. PEM OR protein energy malnutrition
28. nutritional deficiency status
29. an?emia OR iron deficiency an?emia
30. vitamin a deficienc*
31. zinc deficienc *
32. iodine deficienc *
33. muac OR mid-upper arm circumference
34. skinfold thickness
35. anthropometry*
36. or/1-35 (Combines outcome terms)

37. child*
38. infan *
39. baby
40. toddler
41. pre?school*
42. young person
43. Boy
44. Girl
45. or/37-44 (Combines child terms)

46. hand$1 wash* OR hand$1 clean* OR hand$1 disinfect*
47. hand hygiene
48. hand sterility
49. handwashing
50. water improve OR water sediment$ OR water radiat$ OR water irradiati* OR UV
51. sanita*
52. latrine$1 OR toilet$1 OR water closet$1 OR privy OR pour flush OR sewer system$1 OR septic tank$1
53. faeces dispos* OR feces dispos* OR fecal dispos* OR faecal dispos* OR defecation dispos* OR excrement dispos* OR waste dispos* OR excreta dispos* OR faeces manag* OR feces manag* OR fecal manag* OR faecal manag* OR defecation manag* OR excrement manag* OR waste manag* OR excreta manag* OR faeces service* OR feces service* OR fecal service* OR faecal service* OR defecation service* OR excrement service* OR waste service* OR excreta service*
54. water purification OR water microbiology
55. water disinfect* OR water connect* OR water quality OR water handpump$1 OR water standpipe$1 OR water piped
56. water Purif* OR water treat* OR water improv* OR water decontaminat* OR water filt* OR water consum* OR water supply OR water drink* OR water quantity OR water distribut* OR water stor* OR water volume
57. water safe OR water improv* OR water Clean* OR water Hygien*
58. or/46-57 (Combines WASH terms)

59. 36 and 45 and 58 (all concepts combined)

 

Database: Ovid Econlit

$ - truncation term

ab - abstract

adj - adjacent to

ti - title

? - optional wildcard term

1. Stunt$.ab,ti.
2. Short stature.ab,ti.
3. Growth.ab,ti. OR Wast$.ab,ti.
4. Thin.ab,ti.
5. Emaciated.ab,ti.
6. Undernourish$.ab,ti.
7. (BMI OR body mass index).ab,ti.
8. (Intra-uterine growth retardation OR IUGR).ab,ti.
9. Underweight.ab,ti.
10. Weight-for-age.ab,ti.
11. Height-for-age.ab,ti.
12. Length-for-age.ab,ti.
13. Weight-for-height.ab,ti.
14. ((Increas$ OR improve$ OR chang$) adj3 height).ab,ti.
15. ((Increas$ OR improve$ OR chang$) adj3 weight).ab,ti.
16. Body fat percentage.ab,ti.
17. Development$.ab,ti.
18. Under?nutrition.ab,ti.
19. Malnutrition.ab,ti.
20. Nutritional status.ab,ti.
21. Nutriti$.ab,ti.
22. (GAM OR global acute malnutrition).ab,ti.
23. (SAM OR severe acute malnutrition).ab,ti.
24. (PEM OR Protein energy malnutrition).ab,ti.
25. Nutritional deficiency status.ab,ti.
26. (An?emia OR iron deficiency an?emia).ab,ti.
27. Vitamin a deficienc$.ab,ti.
28. Zinc deficienc$.ab,ti.
29. Iodine deficienc$.ab,ti.
30. (MUAC OR mid-upper arm circumference).ab,ti.
31. Skinfold thickness.ab,ti.
32. Anthropometry$.ab,ti
33. Or/1-32 (combines outcome terms)

34. Child$.ab,ti.
35. Infan$.ab,ti.
36. Baby.ab,ti.
37. Toddler.ab,ti.
38. Pre?school$.ab,ti.
39. young person.ab,ti.
40. (Boy OR girl).ab,ti.
41. Or/34-40 (combines child terms)

42. (Hand$1 adj3 (wash$ OR clean$ OR disinfect$)).ab,ti.
43. Hand hygiene.ab,ti.
44. Hand sterility.ab,ti.
45. Handwashing.ab,ti.
46. (water adj3 (improv$ OR sediment$ OR radiat$ OR irradiat$ OR UV)).ti,ab.
47. Sanita$.ab,ti.
48. (Latrine$1 OR toilet$1 OR water closet$1 OR privy OR pour flush OR sewer system$1 OR septic tank$1).ab,ti.
49. ((Faeces OR feces OR fecal OR faecal OR defecation OR excrement OR waste OR excreta) adj3 (dispos$ OR manag$ OR service$)).ab,ti.
50. Water purification.ab,ti.
51. Water microbiology.ab,ti.
52. (Water adj5 (disinfect$ OR connect$ OR quality OR handpump$1 OR standpipe$1 OR piped)).ti,ab.
53. (water adj5 (Purif$ OR treat$ OR improve$ OR decontaminat$ OR filt$ OR consum$ OR supply OR drink$ OR quantity OR distribut$ OR stor$ OR volume)).ab,ti.
54. (water adj3 (safe OR improve$ OR Clean$)).ab,ti.
55. (water adj3 Hygien$).ab,ti.
56. Or/42-55 (combines WASH terms)

57. 33 and 41 and 56 (all concepts combined

 

Database: Greenfile

* - truncation term

N - adjacent to

? - optional wildcard term

1. Stunt* or
2. Short stature or
3. Growth or
4. Wast* or
5. Thin or
6. Emaciated or
7. Undernourish* or
8. BMI or body mass index or
9. Intra-uterine growth retardation or
10. IUGR or
11. Underweight or
12. Weight-for-age or
13. Height-for-age or
14. Length-for-age or
15. Weight-for-height or
16. Increas* N3 height or
17. improve* N3 height or
18. chang* N3 height or
19. Increas* N3 weight or
20. improve* N3 weight or
21. chang* N3 weight or
22. Body fat percentage or
23. Development* or
24. Under?nutrition or
25. Malnutrition or
26. Nutritional status or
27. Nutriti* or
28. GAM or global acute malnutrition or
29. SAM or severe acute malnutrition or
30. PEM or Protein energy malnutrition or
31. Nutritional deficiency status or
32. An?emia or
33. iron deficiency an?emia or
34. Vitamin a deficienc* or
35. Zinc deficienc* or
36. Iodine deficienc* or
37. MUAC or mid-upper arm circumference or
38. Skinfold thickness or
39. Anthropometry*

AND

40. Child* or
41. Infan* or
42. Baby or
43. Toddler or
44. Pre?school* or
45. young person or
46. Boy or
47. girl

AND

48. Hand*1 N3 wash* or
49. Hand* N3 clean* or
50. Hand* N3 disinfect* or
51. Hand hygiene or
52. Hand sterility or
53. Handwashing or
54. water N3 improv* or
55. water N3 sediment* or
56. water N3 radiat* or
57. water N3 irradiat* or
58. UV or
59. Sanita* or
60. Latrine*1 or
61. toilet*1 or
62. water closet*1 or
63. privy or
64. pour flush or
65. sewer system*1 or
66. septic tank*1 or
67. Faeces N3 dispos* or
68. feces N3 dispos* or
69. fecal N3 dispos* or
70. faecal N3 dispos* or
71. defecation N3 dispos* or
72. excrement N3 dispos* or
73. waste N3 dispos* or
74. excreta N3 dispos* or
75. Faeces N3 manag* or
76. feces N3 manag* or
77. fecal N3 manag* or
78. faecal N3 manag* or
79. defecation N3 manag* or
80. excrement N3 manag* or
81. waste N3 manag* or
82. excreta N3 manag* or
83. Faeces N3 service* or
84. feces N3 service* or
85. fecal N3 service* or
86. faecal N3 service* or
87. defecation N3 service* or
88. excrement N3 service* or
89. waste N3 service* or
90. excreta N3 service* or
91. Water purification or
92. Water microbiology or
93. Water N5 disinfect* or
94. Water N5 connect* or
95. Water N5 quality or
96. Water N5 handpump*1 or
97. standpipe*1 or
98. Water N5 piped or
99. water N5 Purif* or
100. water N5 treat* or
101. water N5 improve* or
102. water N5 decontaminat* or
103. water N5 filt* or
104. water N5 consum* or
105. water N5 supply or
106. water N5 drink* or
107. water N5 quantity or
108. water N5 distribut* or
109. water N5 stor* or
110. water N5 volume or
111. water N3 safe or
112. water N3 improve* or
113. water N3 Clean* or
114. water N3 Hygien*

 

Database: Web of Science

* - truncation term

adj - adjacent to

? - optional wildcard term

1. stunt* or
2. short stature or
3. growth or
4. wast* or
5. thin or
6. emaciated or
7. undernourish* or
8. BMI or body mass index or
9. intra-uterine growth retardation or
10. IUGR or
11. underweight or
12. weight-for-age or
13. height-for-age or
14. length-for-age or
15. weight-for-height or
16. Increas* height or
17. improv* height or
18. chang* height or
19. Increas* weight or
20. improv* weight or
21. chang* weight or
22. body fat percentage or
23. development* or
24. under?nutrition or
25. malnutrition or
26. nutritional status or
27. nutrition* or
28. GAM or global acute malnutrition or
29. SAM or severe acute malnutrition or
30. PEM or protein energy malnutrition or
31. nutritional deficiency status or
32. an?emia or
33. iron deficiency an?emia or
34. vitamin a deficienc* or
35. zinc deficienc * or
36. iodine deficienc * or
37. muac or
38. mid-upper arm circumference or
39. skinfold thickness or
40. anthropometry*

AND

41. child* or
42. infan * or
43. baby or
44. toddler or
45. pre?school* or
46. young person or
47. Boy or
48. girl

AND

49. hand*1 wash* or
50. hand*1 clean or
51. hand*1 disinfect* or
52. hand hygiene or hand sterility or
53. handwashing or
54. water improve or
55. water sediment* or
56. water radiat* or
57. water irradiati* or
58. UV or
59. sanita* or
60. latrine*1 or
61. toilet*1 or
62. water closet*1 or
63. privy or
64. pour flush or
65. sewer system*1 or
66. septic tank*1 or
67. faeces dispos* or
68. feces dispos* or
69. fecal dispos* or
70. faecal dispos* or
71. defecation dispos* or
72. excrement dispos* or
73. waste dispos* or
74. excreta dispos* or
75. faeces manag* or
76. feces manag* or
77. fecal manag* or
78. faecal manag* or
79. defecation manag* or
80. excrement manag* or
81. waste manag* or
82. excreta manag* or
83. faeces service* or
84. feces service* or
85. fecal service* or
86. faecal service* or
87. defecation service* or
88. excrement service* or
89. waste service* or
90. excreta service* or
91. water purification or
92. water microbiology or
93. water disinfect* or
94. water connect* or
95. water quality or
96. water handpump*1 or
97. water standpipe*1 or
98. water piped or
99. water Purif* or
100. water treat* or
101. water improv* or
102. water decontaminat* or
103. water filt* or
104. water consum* or
105. water supply or
106. water drink* or
107. water quantity or
108. water distribut* or
109. water stor* or
110. water volume or
111. water safe or
112. water improv* or
113. water Clean* or
114. water Hygien*

 

Appendix 2. Chinese search terms


Category关于营养/健康状况关于水和卫生关于青少年

Nutrition/HealthWater/SanitationObject of study

Database数据库: CBM


Search terms身高/体重改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

Height/weightImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

血红蛋白/转铁蛋白改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

Haemoglobin/transferrinImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

皮脂厚度/脂肪含量改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

Skinfold thickness/fat contentImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

营养不良/上臂围改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

Malnutrition/upper arm circumferenceImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

出生体重/小于胎龄儿改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

Birth weight/gestational age childrenImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

肠道感染改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

Intestinal infectionImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

体质指数/BMI改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

BMIImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

锌/碘改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

Zinc/iodineImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

维生素改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

VitaminImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

蛔虫改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

RoundwormsImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

腹泻改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

DiarrhoeaImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

伤寒/副伤寒改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

Typhoid/paratyphoidImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

肝炎改水/改厕/洗手/粪便/(粪便无害化)/水净化< 18岁

HepatitisImprove drinking water/lavatories/excrement (harmless)/Water purification< 18 years

DatabasesCNKI and VIP


Search terms身高/体重改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

Height/weightImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants

血红蛋白/转铁蛋白改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

Hemoglobin/transferrinImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants

皮脂厚度/脂肪含量改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

Skinfold thickness/fat contentImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants

营养不良/上臂围改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

Malnutrition/upper arm circumferenceImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants

出生体重/小于胎龄儿改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

Birth weight/gestational age childrenImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants

肠道感染/腹泻改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

Intestinal infection/diarrhoeaImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants

体质指数/BMI改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

BMIImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants

锌/碘/维生素改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

Zinc/iodine/vitaminImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants

肝炎改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

HepatitisImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants

蛔虫改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

RoundwormsImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants

伤寒/副伤寒改水/改厕/洗手/粪便/(粪便无害化)/水净化青年/少年/婴儿/幼儿/儿童/新生儿

Typhoid/paratyphoidImprove drinking water/lavatories/excrement (harmless)/Water purificationYouth/Junior/Infant/young children/children/infants



 

History

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

Protocol first published: Issue 10, 2011
Review first published: Issue 8, 2013


DateEventDescription

12 August 2011AmendedProtocol FINAL

3 August 2011AmendedProtocol: Amended according to external peer reviewer feedback.

18 May 2011AmendedProtocol: Amended according to internal reviewer feedback.



 

Contributions of authors

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

The following assignation of tasks has been agreed to by all authors.

Draft the protocol: all

Study selection: LW, SB

Review Chinese databases: YC

Extract data from studies: LW, SB

Enter data into RevMan: LW

Carry out the analysis: LW, EA

Interpret the analysis: LW, EA, ADD

Draft the final review: all

Disagreement resolution: ADD

Update the review: ADD

 

Declarations of interest

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

Subsequent to the inception of this review and the publication of the review protocol, ADD has been seconded part-time as a Senior Research Fellow in the Agriculture Team of the Research and Evidence Division at the UK Department for International Development (DFID). YV and SC are employees of WaterAid, an international non-governmental organisation that works to promote the provision of safe water, improved sanitation and hygiene globally. YV and SC were involved in the conceptualisation of the review, contributed to the literature search and provided comments on the review drafts. YV and SC were not involved in data extraction, data analysis or interpretation of the findings. All other authors have no known potential conflict of interest.

 

Sources of support

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms
 

Internal sources

  • No sources of support supplied

 

External sources

  • Department of International Development (DFID), UK.
    This research was made possible with UK aid from DFID as part of the SHARE research programme (www.SHAREresearch.org).

 

Differences between protocol and review

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. History
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Index terms

None.

* Indicates the major publication for the study

References

References to studies included in this review

  1. Top of page
  2. AbstractRésumé
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. History
  14. Contributions of authors
  15. Declarations of interest
  16. Sources of support
  17. Differences between protocol and review
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to ongoing studies
  22. Additional references
Ahmed 1993 {published data only}
  • Ahmed NU, Zeitlin MF, Beiser AS, Super CM, Gershoff SN. A longitudinal study of the impact of behavioural change intervention on cleanliness, diarrhoeal morbidity and growth of children in rural Bangladesh. Social Science & Medicine 1993;37(2):159-71.
  • Ahmed NU, Zeitlin MF, Beiser AS, Super CM, Gershoff SN, Ahmed MA. Assessment of the impact of a hygiene intervention on environmental sanitation, childhood diarrhoea, and the growth of children in rural Bangladesh. Food and Nutrition Bulletin 1994;15:40-52.
Arnold 2009 {published data only (unpublished sought but not used)}
  • Arnold B, Arana B, Mausezahl D, Hubbard A, Colford JM. Evaluation of a pre-existing, 3-year household water treatment and handwashing intervention in rural Guatemala. International Journal of Epidemiology 2009;38(6):1651-61.
Bowen 2012 {published and unpublished data}
  • Bowen A, Agboatwalla M, Luby S, Tobery T, Ayers T, Hoekstra RM. Association between intensive handwashing promotion and child development in Karachi, Pakistan. Archives of Pediatric & Adolescent Medicine 2012;166(11):1037-44.
Du Preez 2010 {published and unpublished data}
  • Du Preez M, McGuigan KG, Conroy RM. Solar disinfection of drinking water in the prevention of dysentery in South African children aged under 5 years: the role of participant motivation. Environmental Science & Technology 2010;44(22):8744-9.
Du Preez 2011 {published and unpublished data}
  • du Preez M, Conroy RM, Ligondo S, Hennessy J, Elmore-Meegan M, Soita A, et al. Randomized intervention study of solar disinfection of drinking water in the prevention of dysentery in Kenyan children aged under 5 years. Environmental Science & Technology 1990;45(21):9315-23.
Fenn 2012 {published data only}
Guzman 1968 {published data only}
  • Guzman MA, Scrimshaw NS, Bruch HA, Gordon JE. Nutrition and infection field study in Guatemalan villages, 1958-1964. VII. Physical growth and development of preschool children. Archives of Environmental Health 1968;17(1):107-18.
Hasan 1989 {published data only}
  • Aziz KM, Hoque BA, Huttly SR. Water supply, sanitation and hygiene education: report of a health impact study in Mirzapur, Bangladesh. WASH Report Series, Water and Sanitation Program. UNDP/World Bank, 1990.
  • Hasan KZ, Briend A, Aziz KM, Hoque BA, Patwary MY, Huttly SR. Lack of impact of a water and sanitation intervention on the nutritional status of children in rural Bangladesh. European Journal of Clinical Nutrition 1989;43(12):837-43.
Huttly 1990 {published data only}
  • Ajala M, Akujobi C, Blum D, Cairncross S, Carson D, Dosunmu-Ogunbi O, et al. Evaluating water and sanitation projects: Lessons from Imo State, Nigeria. Health Policy and Planning 1989;4(1):40-9.
  • Huttly SR, Blum D, Kirkwood BR, Emeh RN, Okeke N, Ajala M, et al. The Imo State (Nigeria) drinking water supply and sanitation project, 2. Impact on dracunculiasis, diarrhoea and nutritional status. Transactions of the Royal Society of Tropical Medicine & Hygiene 1990;84(2):316-21.
Langford 2011 {published data only (unpublished sought but not used)}
Luby 2004 {published and unpublished data}
  • Luby SP, Agboatwalla M, Painter J, Altaf A, Billhimer WL, Hoekstra RM. Effect of intensive handwashing promotion on childhood diarrhoea in high-risk communities in Pakistan: a randomised controlled trial. JAMA 2004;291(21):2547-54.
Luby 2006 {published and unpublished data}
Luby 2006 (Floc & Bleach) {published and unpublished data}
Luby 2006 (Soap) {published and unpublished data}
Luby 2006 (Soap & Floc) {published and unpublished data}
McGuigan 2011 {published and unpublished data}
  • McGuigan KG, Samaiyar P, Du Preez M, Conroy R. A high compliance randomised controlled field trial of solar disinfection (SODIS) of drinking water and its impact on childhood diarrhoea in rural Cambodia. Environmental Science & Technology 2011;45(18):7862-7.
Schlesinger 1983 {published data only}
  • Schlesinger L, Weinberger J, Figueroa G, Secure T, González N, Mónckeberg F. Environmental sanitation: a nutrition intervention. Nutrition Intervention Strategies in National Development. Underwood Academy. Academic Press, Inc., 1983:241.

References to studies excluded from this review

  1. Top of page
  2. AbstractRésumé
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. History
  14. Contributions of authors
  15. Declarations of interest
  16. Sources of support
  17. Differences between protocol and review
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to ongoing studies
  22. Additional references
Anderson 1981 {published data only}
  • Anderson MA. Health and nutrition impact of potable water in rural Bolivia. Journal of Tropical Pediatrics 1981;27(7):39-46.
Anon, 1981 {published data only}
  • Anon. Infections as deterrents of child growth. Nutrition Reviews 1981;39(9):328-30.
Anon, 1990 {published data only}
  • Anon. Child health: its relationship with water supplies and hygiene practices in rural Sri Lanka. Tropical Medicine and Parasitology 1990;41(1):77-120.
Barros 2008 {published data only}
  • Barros AJD, Santos IS, Matijasevich A, Araujo CL, Gigante DP, Menezes AMB, et al. Methods used in the 1982, 1993, and 2004 birth cohort studies from Pelotas, Rio Grande do Sul State, Brazil, and a description of the socio-economic conditions of participants' families. Cadernos de Saude Publica 2008;24 Suppl 3:S371-80.
Buttenheim 2008 {published data only}
Checkley 2004 {published data only}
  • Checkley W, Gilman RH, Black RE, Epstein LD, Cabrera L, Sterling CR, et al. Effect of water and sanitation on childhood health in a poor Peruvian peri-urban community. Lancet 2004;363(9403):1128.
Chen 2005 {published data only}
  • Chen Y, Xu L. Impact of hands cleanliness on diminution of Ascardes lumbricoides reinfection in pupils. China Journal of Parasitology Disease Control 2005;18(2):132-3.
Chiang 1991 {published data only}
  • Chiang A, Hernandez E, Figueras F, Maleras DM, Rodriguez X. Effect of the water supply on the nutritional state of children under 5 years old in rural locations. Revista Cubana de Alimentacion y Nutricion 1991;5(1):56-9.
Chirwa 2008 {published data only}
Cousens 1990 {published data only}
  • Cousens SN, Mertens TE, Fernando MA. The anthropometric status of children in Kurunegala district in Sri Lanka: its relation to water supply, sanitation and hygiene practice. Tropical Medicine & Parasitology 1990;41(1):105-14.
Daniels 1991 {published data only}
  • Daniels DL, Cousens SN, Makoae LN, Feachem RG. A study of the association between improved sanitation facilities and children's height in Lesotho. European Journal of Clinical Nutrition 1991;45(1):23-32.
Dong 2009 {published data only}
  • Dong X, Xu W, Li L. Effect of handwashing intervention on kindergarten children in Tianjin. Chinese Journal of School Health 2009.
Esrey 1988 {published data only}
  • Esrey SA, Habicht JP, Latham MC, Sisler DG, Casella G. Drinking water source, diarrhoeal morbidity, and child growth in villages with both traditional and improved water supplies in rural Lesotho, southern Africa. American Journal of Public Health 1988;78(11):1451-5.
Esrey 1992 {published data only}
  • Esrey SA, Habicht JP, Casella G. The complementary effect of latrines and increased water usage on the growth of infants in rural Lesotho. American Journal of Epidemiology 1992;135(6):659-66.
Esrey 1996 {published data only}
  • Esrey SA. Water, waste, and well-being: a multi-country study. American Journal of Epidemiology 1996;143(6):608-23.
Etiler 2004 {published data only}
Farah 2007 {published data only}
  • Farah N, Samina S, Ali SS. Effects of water and sanitation on childhood nutrition in Pakistan. Pakistan Paediatric Journal 2007;31(2):69-74.
Fernandez 1969 {published data only}
  • Fernandez NA, Burgos JC, Asenjo CF, Rosa IR. Nutrition survey of two rural Puerto Rican areas before and after a Community Improvement Program. American Journal of Clinical Nutrition 1969;22:1639-51.
Fikree 2000 {published data only}
  • Fikree FF, Rahbar MH, Berendes HW. Risk factors for stunting and wasting at age six, twelve and twenty-four months for squatter children of Karachi, Pakistan. Journal of the Pakistan Medical Association 2000;50(10):341-8.
Gokhale 1994 {published data only}
  • Gokhale MK, Chiplonkar SA, Sukhatme PV. Effect of environmental factors on growth and morbidity of urban Montessori children receiving supplementation. Ecology of Food and Nutrition 1994;31(3/4):269-76.
Guerrant 1983 {published data only}
  • Guerrant RL, Kirchhoff LV, Shields DS. Prospective study of diarrhoeal illness in northeastern Brazil: Patterns of disease, nutritional impact, etiologies, and risk factors. Journal of Infectious Diseases 1983;148(6):986-97.
Hartinger 2011a {published data only}
  • Hartinger S, Hattendorf J, Lanata C, Gil A, Verastegui H, Mausezahl D. Integrating home-based environmental interventions (IHIP): A community-randomised trial to improve indoor air pollution, drinking water quality and child nutrition in rural Peru. Tropical Medicine and International Health. Conference: 7th European Congress on Tropical Medicine and International Health Barcelona Spain 2011;6:354-5.
Hartinger 2011b {published data only}
  • Hartinger SM, Lanata CF, Hattendorf J, Gil AI, Verastegui H, Ochoa T, et al. A community randomised controlled trial evaluating a home-based environmental intervention package of improved stoves, solar water disinfection and kitchen sinks in rural Peru: Rationale, trial design and baseline findings. Contemporary Clinical Trials 2011;32(6):864-73.
Hebert 1984 {published data only}
Hebert 1985a {published data only}
Hebert 1985b {published data only}
  • Hebert JR. Effects of water quality and water quantity on nutritional status: Findings from a south Indian community. Bulletin of the World Health Organization 1985;63(1):145-55.
Henry 1981 {published data only}
  • Henry FJ. Environmental sanitation infection and nutritional status of infants in rural St. Lucia, West Indies. Transactions of the Royal Society of Tropical Medicine & Hygiene 1981;75(4):507-13.
Hoek 2002 {published data only}
  • Hoek W, van der Feenstra SG, Konradsen F. Availability of irrigation water for domestic use in Pakistan: its impact on prevalence of diarrhoea and nutritional status of children. Journal of Health, Population and Nutrition 2002;20(1):77-84.
Hou 2010 {published data only}
  • Hou C, Fu G, Zeng Q, Liu H. Studies on the effect of changing water in high water-iodine area in Tianjin. Chinese Journal of the Control of Endemic Disease 2010;25(6):444-5.
Li 1996 {published data only}
  • Li FJ, Ou QY, Huang DJ, Liu ZE, Li SM. A study on prevention of diarrhoeal diseases and improvement of case management in children of Hunan province. Disease Surveillance 1996;12(3):87-9.
Lindskog 1987 {published data only}
  • Lindskog U, Lindskog P, Gebre-Medhin M. Child health and household water supply: a longitudinal study of growth and its environmental determinants in rural Malawi. Human Nutrition - Clinical Nutrition 1987;41(6):409-23.
Lindskog 1988 {published data only}
  • Lindskog U, Lindskog P, Carstensen J, Larsson Y, Gebre-Medhin M. Childhood mortality in relation to nutritional status and water supply--a prospective study from rural Malawi. Acta Paediatrica Scandinavica 1988;77(2):260-8.
Lindskog 1994 {published data only}
  • Lindskog U, Bjorksten B, Gebre-Medhin M. Infant care in rural Malawi. A prospective study of morbidity and growth in relation to environmental factors. Annals of Tropical Paediatrics 1994;14(1):37-45.
Lopez de Romana 1989 {published data only}
  • Lopez de Romana G, Brown KH, Black RE, Kanashiro HC. Longitudinal studies of infectious diseases and physical growth of infants in Huascar, an underprivileged peri-urban community in Lima, Peru. American Journal of Epidemiology 1989;129(4):769-84.
Lye 1984 {published data only}
  • Lye MS. Diarrhoeal diseases in rural Malaysia: risk factors in young children. Annals of the Academy of Medicine 1984;13(2):156-62.
Ma 2007 {published data only}
  • Ma H, Bowen A, Ou JM, Zeng G  . Evaluating effect of handwashing intervention among primary students of counties in Fujian Province. Chinese Journal of Public Health 2007;23(8):989-91.
Malekafzali 2000 {published data only}
  • Malekafzali H, Abdollahi Z, Mafi A, Naghavi M. Community-based nutritional intervention for reducing malnutrition among children under 5 years of age in the Islamic Republic of Iran. Eastern Mediterranean Health Journal 2000;6(2/3):238-45.
Merchant 2003 {published data only}
Moy 1991 {published data only}
Nisbet 1974 {published data only}
  • Nisbet BR. The effect of fluoridation of the water supply on the growth of children. Health Bulletin 1974;32(4):140-6.
Parent 2002 {published data only}
  • Parent G, Zagre NM, Ouedraogo A, Guiguembe TR. Are large-scale water facilities in Burkina Faso helping to improve child nutrition?. Cahiers Agricultures 2002;11(1):51-7.
Sanou 2011 {published data only}
  • Sanou D, Turgeon-O'Brien H, Desrosiers T. Impact of an integrated nutrition intervention on nutrient intakes, morbidity and growth of rural Burkinabe preschool children. African Journal of Food, Agriculture, Nutrition and Development 2011;11(4):4968-84.
Stoler 2011 {published data only}
  • Stoler J, Fink G, Weeks JR, Otoo RA, Ampofo JA, Hill AG. When urban taps run dry: Sachet water consumption and health effects in low income neighbourhoods of Accra, Ghana. Health & Place 2011;18(2):250-62.
Wang 2010 {published data only}
  • Wang M, Li H, Wu R, Zhang GQ, Li J, Li XJ, et al. Survey on resident's iodine level in high iodine area after taking low iodine water in Shouguang City. Preventive Medicine Tribune 2010;16(11):1010-1.
Xiong 2010 {published data only}
  • Xiong M, Dong Y, Zhang Y, et al. Survey of results of modification of toilets in rural areas of Yunnan Province in control of schistosomiasis. China Tropical Medicine 2010;10(3):300-4.
Xu 2001 {published data only}
  • Xu LQ, Xiao DH, Zhou CH, Zhang XQ, Lan SG, Zhen XX, et al. Cleanliness of hands in diminution of Ascardes lumbricoides infection in children. Chinese Journal of Parasitology & Parasitic Diseases 2001;19(5):294.
Yang 2006 {published data only}
  • Yang SM, Zhao XH, Yang JJ, Zhang GY, Yang JY. Hygiene evaluation of the program of child environment and environmental sanitation in Gansu province. Health, Occupation and Education 2006;24(1):135-6.
Yao 2000 {published data only}
  • Yao H, Chen Y, Liu K, et al. Studies on the levels of iron, magnesium, copper and zinc in serum among population after water improvement for 10 years in areas with endemic Fluorosis-Arsenism. Journal of Environment & Health 2000;17(2):98-9.
Zhang 1999 {published data only}
  • Zhang TJ, Wang SL, Wang JR. Evaluation of the effect of health education intervention to prevent diarrhoea among children under 5 years old. Chinese Journal of Health Education 1999;15(7):19-21.
Zhang 2000 {published data only}
  • Zhang W,  Liu M, Yin W, Zhang H, Li G, Liu L, et al. Evaluation of a long-term effect on improving drinking water and lavatories in rural areas for prevention of diseases. Chinese Journal of Disease Control & Prevention 2000;4(1):76-8.
Zhang 2012 {published data only}
  • Zhang J. The impact of water quality on health: evidence from the drinking water infrastructure program in rural China. Journal of Health Economics 2012;31(1):122-34.
Zhu 1997a {published data only}
  • Zhu XL, Du XM, Xue JR, Wang JJ. Macro effects of improving lavatories to prevent diseases in population of trial rural areas. Chinese Journal of Public Health 1997;13(7):420-1.
Zhu 1997b {published data only}
  • Zhu XL, Xia QY, Meng ZY, Wang XC, Shao BC, Yang SY, et al. Assessment of effects of disease prevention by intervention measures of school environmental hygiene in rural areas. Journal of Hygiene Research 1997;6:378-80.

References to ongoing studies

  1. Top of page
  2. AbstractRésumé
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. History
  14. Contributions of authors
  15. Declarations of interest
  16. Sources of support
  17. Differences between protocol and review
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to ongoing studies
  22. Additional references
SHARE {published data only}
  • Clasen T, Boisson S, Routray P, Cumming O, Jenkins M, Ensink JHJ, et al. The effect of improved rural sanitation on diarrhoea and helminth infection: design of a cluster-randomised trial in Orissa, India. Emerging Themes in Epidemiology 2012;9(1):7.
SHINE {published data only}
  • Johns Hopkins Bloomberg School of Public Health. Sanitation, Hygiene, Infant Nutrition Efficacy Project (SHINE). http://clinicaltrials.gov/ct2/show/NCT01824940.
WASH Benefits {published data only}
  • Innovations for Poverty Action. WASH Benefits Bangladesh: A Cluster Randomized Controlled Trial of the Benefits of Water, Sanitation, Hygiene Plus Nutrition Interventions on Child Growth. http://clinicaltrials.gov/show/NCT01590095;. [: NCT01590095]
  • Innovations for Poverty Action. WASH Benefits Kenya: A Cluster Randomized Controlled Trial of the Benefits of Sanitation, Water Quality, Handwashing, and Nutrition Interventions on Child Health and Development. http://www.clinicaltrials.gov/ct2/show/NCT01704105.
WSP - Handwashing {published data only}
  • No reference available. Global Scaling Up Handwashing Project. http://www.wsp.org/global-initiatives/global-scaling-handwashing-project.
WSP - Sanitation {published data only}
  • No reference available. Global Scaling Up Sanitation Project. http://www.wsp.org/global-initiatives/global-scaling-sanitation-project.

Additional references

  1. Top of page
  2. AbstractRésumé
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. History
  14. Contributions of authors
  15. Declarations of interest
  16. Sources of support
  17. Differences between protocol and review
  18. Characteristics of studies
  19. References to studies included in this review
  20. References to studies excluded from this review
  21. References to ongoing studies
  22. Additional references
Arnold 2012
  • Arnold BF, Mäusezahl D, Schmidt W-P, Christen A, Colford JM Jr. Comment on randomised intervention study of solar disinfection of drinking water in the prevention of dysentery in Kenyan children aged under 5 years. Environmental Science and Technology 2012;46(5):3031-2.
Black 2013
  • Black RE, Victora CG, Walker SP, Bhutta ZA, Christian P, de Onis M, et al. Maternal and child undernutrition and overweight in low-income and middle-income countries. Lancet 2013 Jun 6 [Epub ahead of print]. [DOI: 10.1016/S0140-6736(13)60937-X]
Briend 1990
  • Briend A. Is diarrhoea a major cause of malnutrition among the under-fives in developing countries? A review of available evidence. European Journal of Clinical Nutrition 1990;44(9):611-28.
Checkley 2008
  • Checkley W, Buckley G, Gilman RH, Assis AMO, Guerrant RL, Morris SS, et al. Multi-country analysis of the effects of diarrhoea on childhood stunting. International Journal of Epidemiology 2008;37(4):816.
Clasen 2006
Clasen 2010
Ejemot 2008
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