Effectiveness of interventions to improve drinking water, sanitation, and handwashing with soap on risk of diarrhoeal disease in children in low-income and middle-income settings: a systematic review and meta-analysis

In the paper

“These estimates are not disaggregated by sex, despite calls and guidelines to do so in public health11, 12 and in the WASH sector.13”

What the sources say

• Partly supported

  In “Measurement and meaning: reporting sex in health research” (page not given), the authors call for more sex-related reporting and an accountability revolution in health research. That supports the public-health call cited here, but the paper does not provide a guideline for sex-disaggregating disease-burden estimates. The WASH-sector claim is attached to a different citation. (LLM, conf=0.82)

  cites [11] Hawkes S Haseen F Aounallah-Skhiri H Measurement and meaning: reporting sex in health research Lancet 393 2019 497 499 30739669 sourceExperimental — accuracy not yet measured
• Supported

  The Results > SAGER guidelines section calls for research data to be reported disaggregated by sex, including data relevant to health problems. This supports the public-health-guidelines portion attributed to this source; the sentence does not attribute the WASH-specific guidelines or the status of WASH burden estimates to it. (LLM, conf=0.92)

  cites [12] Heidari S Babor TF De Castro P Tort S Curno M Sex and Gender Equity in Research: rationale for the SAGER guidelines and recommended use Res Integr Peer Rev 1 2016 2 29451543 PMC5793986 source
• Not checked yetcites [13] Caruso BA Sinharoy SS Gender data gaps represent missed opportunities in WASH Lancet Glob Health 7 2019 e1617 31708141 source

In the paper

“Further examined covariates, including improved sanitation (p=0·35) and rural setting (p=0·37), were not associated with risk of diarrhoeal disease; appendix 2 p 13).”

In the paper

“The total study population included 62 616 children in the drinking water analysis, 40 799 children in the sanitation analysis, and 98 416 children in the hygiene analysis.”

In the paper

“The meta-regression model explained 11% of the between-study variance of drinking water studies.”

In the paper

“21 290 records were identified from the search, of which 15 634 were screened and 83 assessed for eligibility (figure 3).”

In the paper

“23 new studies were added to the previous meta-analyses, including 12 new comparisons for the water analysis, seven for the sanitation analysis, and ten for the hygiene analysis.”

In the paper

“This systematic review contains evidence from 124 WASH interventions.”

In the paper

“Only four studies of drinking water (three POU filter studies36, 37, 38 and one POU chlorine study39) reported results by sex; thus, our estimates are not disaggregated by sex (appendix 1 pp 5–7).”

What the sources say

• Not checked yetcites [36] Aiken BA Stauber CE Ortiz GM Sobsey MD An assessment of continued use and health impact of the concrete biosand filter in Bonao, Dominican Republic Am J Trop Med Hyg 85 2011 309 317 21813853 PMC3144831 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [37] Brown J Improving household drinking water quality: use of ceramic water filters in Cambodia https://www.wsp.org/sites/wsp/files/publications/926200724252_eap_cambodia_filter.pdf August, 2007
• Not checked yetcites [38] Brown J Sobsey MD Loomis D Local drinking water filters reduce diarrheal disease in Cambodia: a randomized, controlled trial of the ceramic water purifier Am J Trop Med Hyg 79 2008 394 400 18784232 source
• Not checked yetcites [39] Harshfield E Lantagne D Turbes A Null C Evaluating the sustained health impact of household chlorination of drinking water in rural Haiti Am J Trop Med Hyg 87 2012 786 795 22987657 PMC3516252 source

In the paper

“In total, 124 studies were included in this systematic review, with 83 drinking water comparisons (78 separate studies), 20 sanitation comparisons (19 separate studies), and 41 hygiene comparisons (41 separate studies).”

In the paper

“Scarce evidence was available for this exposure category; thus, addition of new evidence substantially changed estimates.”

In the paper

“Around half of the handwashing interventions focused on handwashing promotion with or without soap provision, whereas the other half of interventions involved broader hygiene education, such as on food and kitchen hygiene or on safe drinking water and sanitation.”

In the paper

“Nevertheless, pooled RRs were remarkably close comparing household or community versus institutional setting, low-income, and middle-income versus high-income settings, or different hygiene interventions.”

In the paper

“In these interventions, drinking water was not free from microbial contamination24, 95 and was still stored at household level85 after intervention implementation.”

What the sources say

• Not checked yetcites [24] Hunter PR Ramírez Toro GI Minnigh HA Impact on diarrhoeal illness of a community educational intervention to improve drinking water quality in rural communities in Puerto Rico BMC Public Health 10 2010 219 20426831 PMC2876105 source
• Not checked yetcites [95] Pickering AJ Crider Y Sultana S Effect of in-line drinking water chlorination at the point of collection on child diarrhoea in urban Bangladesh: a double-blind, cluster-randomised controlled trial Lancet Glob Health 7 2019 e1247 e1256 31402005 source
• Not checked yetcites [85] Ercumen A Arnold BF Kumpel E Upgrading a piped water supply from intermittent to continuous delivery and association with waterborne illness: a matched cohort study in urban India PLoS Med 12 2015 e1001892 PMC4624240 26505897 source

In the paper

“No sanitation studies reported results by sex.”

In the paper

“Only one handwashing intervention reported results by sex.78”

What the sources say

• Not checked yetcites [78] Roberts L Jorm L Patel M Smith W Douglas RM McGilchrist C Effect of infection control measures on the frequency of diarrheal episodes in child care: a randomized, controlled trial Pediatrics 105 2000 743 746 10742314 source

In the paper

“We identified only two studies for the transition from improved water source on premises to improved source, on premises, and higher water quality,24, 95 and one study for the transition from improved water source on premises to improved source, on premises, and continuous supply.85”

What the sources say

• Not checked yetcites [24] Hunter PR Ramírez Toro GI Minnigh HA Impact on diarrhoeal illness of a community educational intervention to improve drinking water quality in rural communities in Puerto Rico BMC Public Health 10 2010 219 20426831 PMC2876105 source
• Not checked yetcites [95] Pickering AJ Crider Y Sultana S Effect of in-line drinking water chlorination at the point of collection on child diarrhoea in urban Bangladesh: a double-blind, cluster-randomised controlled trial Lancet Glob Health 7 2019 e1247 e1256 31402005 source
• Not checked yetcites [85] Ercumen A Arnold BF Kumpel E Upgrading a piped water supply from intermittent to continuous delivery and association with waterborne illness: a matched cohort study in urban India PLoS Med 12 2015 e1001892 PMC4624240 26505897 source

In the paper

“Safe and reliable drinking water, sanitation that separates excreta from human contact, and handwashing with soap at key times, such as after potential faecal contact and before eating or preparing food, have positive effects on health and social and economic wellbeing.1, 2, 3, 4, 5”

What the sources say

• Not checked yetcites [1] Clasen TF Alexander KT Sinclair D Interventions to improve water quality for preventing diarrhoea Cochrane Database Syst Rev 10 2015 CD004794 PMC4625648 26488938
• Not checked yetcites [2] Ejemot-Nwadiaro RI Ehiri JE Arikpo D Meremikwu MM Critchley JA Hand-washing promotion for preventing diarrhoea Cochrane Database Syst Rev 12 2021 CD004265 PMC8094449 33539552
• Not checked yetcites [3] Freeman MC Garn JV Sclar GD The impact of sanitation on infectious disease and nutritional status: a systematic review and meta-analysis Int J Hyg Environ Health 220 2017 928 949 28602619 source
• Not checked yetcites [4] Sclar GD Penakalapati G Caruso BA Exploring the relationship between sanitation and mental and social well-being: a systematic review and qualitative synthesis Soc Sci Med 217 2018 121 134 30316053 source
• Not checked yetcites [5] Wolf J Hunter PR Freeman MC Impact of drinking water, sanitation and handwashing with soap on childhood diarrhoeal disease: updated meta-analysis and meta-regression Trop Med Int Health 23 2018 508 525 29537671 source

In the paper

“For the work of the Commission, updated estimates of disease burden attributable to WASH are needed, which require up-to-date estimates for the effect of different WASH exposures on risk of diarrhoea.”

In the paper

“The funders of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the report.”

In the paper

“These results include those from three large, high-quality WASH trials, which led to discussion and questions about the health effects of basic WASH interventions (eg, provision of improved latrines or POU treatment of drinking water).16”

What the sources say

• Not checked yetcites [16] Cumming O Arnold BF Ban R The implications of three major new trials for the effect of water, sanitation and hygiene on childhood diarrhea and stunting: a consensus statement BMC Med 17 2019 173 31462230 PMC6712663 source

In the paper

“Risk of bias in individual studies was assessed by use of a modified Newcastle-Ottawa Scale,28 considering seven areas of bias: selection bias, response bias, follow-up bias, misclassification bias, assessment of bias in outcome, measurement of bias in outcome, and bias in analysis. Each study was assigned a score of up to nine, with a higher score indicating a smaller risk of bias (appendix 1 pp”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [28] Wells G Shea B O'Connell D The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp

In the paper

“A systematic review focusing on the effects of sewerage on incidence of diarrhoea included intervention and non-intervention studies, and searched the literature from Jan 1, 1966, to Feb 28, 2010.14”

What the sources say

• Not checked yetcites [14] Norman G Pedley S Takkouche B Effects of sewerage on diarrhoea and enteric infections: a systematic review and meta-analysis Lancet Infect Dis 10 2010 536 544 20620115 source

In the paper

“The UN's Sustainable Development Goals (SDGs) include dedicated WASH targets (SDGs 6.1 and 6.2), which explicitly emphasise equity, address hygiene, and call for higher levels of drinking water and sanitation services for all,7 and are linked to all other SDGs.8”

What the sources say

• Not checked yetcites [7] UN Transforming our world: the 2030 Agenda for Sustainable Development 2015 United Nations New York, NY
• Not checked yetcites [8] UN Water Water and sanitation interlinkages across the 2030 Agenda for Sustainable Development 2016 United Nations Water Geneva

In the paper

“We assessed the body of evidence by intervention type using a modified Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach.29 We then used the five GRADE criteria to potentially downgrade the initial rating: risk of bias in individual studies, inconsistency (I2 >90%), indirectness, imprecision, and publication bias (appendix 2 pp 22–23).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [29] Schünemann HJ Brozek J Guyatt G Oxman AD GRADE handbook: introduction to GRADE handbook https://gdt.gradepro.org/app/handbook/handbook.html#h.w6r7mtvq3mjz 2013

In the paper

“According to the WHO–UNICEF Joint Monitoring Programme for Water Supply, Sanitation and Hygiene, in 2020, 2·0 billion people did not have access to safely managed drinking water services, 3·6 billion did not have access to safely managed sanitation services, and 2·3 billion did not have access to handwashing facilities with soap and water at home.9”

What the sources say

• Not checked yetcites [9] WHO UNICEF Progress on household drinking water, sanitation and hygiene 2000–2020: five years into the SDGs 2021 World Health Organization and the United Nations Children's Fund Geneva

In the paper

“Two reviewers (JW and SH) screened study titles, abstracts, and full texts. These two reviewers were not involved in any of the included studies as a result of this new search. Any conflicts between the reviewers were resolved through consensus with a third reviewer (SB).”

In the paper

“Frequently updated exposure–response relationships from systematic reviews are also needed for annual reporting of progress towards SDG 3 to ensure health and wellbeing for all, and specifically for target 3.9.2 on WASH-related mortality.17”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [17] WHO SDG 3.9.2 WASH deaths. The Global Health Observatory https://www.who.int/data/gho/data/indicators/indicator-details/GHO/sdg-3-9-2-wash-deaths 2022

In the paper

“This systematic review and meta-analysis followed Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines.33”

What the sources say

• Not checked yetcites [33] Page MJ McKenzie JE Bossuyt PM The PRISMA 2020 statement: an updated guideline for reporting systematic reviews BMJ 372 2021 n71 33782057 PMC8005924

In the paper

“The same two reviewers independently extracted data and assessed risk of bias. Any conflicts between reviewers over data extraction and bias assessment were resolved by discussion.”

In the paper

“Previous systematic reviews on WASH interventions and diarrhoea provided effect estimates for basic sanitation interventions3 or point-of-use (POU) water treatment.1”

What the sources say

• Not checked yetcites [3] Freeman MC Garn JV Sclar GD The impact of sanitation on infectious disease and nutritional status: a systematic review and meta-analysis Int J Hyg Environ Health 220 2017 928 949 28602619 source
• Not checked yetcites [1] Clasen TF Alexander KT Sinclair D Interventions to improve water quality for preventing diarrhoea Cochrane Database Syst Rev 10 2015 CD004794 PMC4625648 26488938

In the paper

“A systematic review on different types of WASH interventions searched the literature up to early 2016 and found only one study reporting provision of higher-quality piped water and two studies of continuous water supply.5”

What the sources say

• Not checked yetcites [5] Wolf J Hunter PR Freeman MC Impact of drinking water, sanitation and handwashing with soap on childhood diarrhoeal disease: updated meta-analysis and meta-regression Trop Med Int Health 23 2018 508 525 29537671 source

In the paper

“Basic sanitation services without sewer connection were graded as moderate certainty evidence and basic sanitation services with sewer connection were graded as very low certainty evidence mainly due to the non-randomised study designs and high risk of bias in services with sewer connection (appendix 2 pp 22–24).”

In the paper

“POU interventions were graded as moderate certainty evidence and all other water interventions as very low certainty evidence (appendix 2 pp 22–24).”

In the paper

“This study is registered with PROSPERO, CRD42016043164.”

In the paper

“Two reviewers independently extracted study-level data and assessed risk of bias using a modified Newcastle-Ottawa Scale and certainty of evidence using a modified Grading of Recommendations, Assessment, Development, and Evaluation approach.”

In the paper

“Drinking water interventions, specifically drinking water of higher quality and water filtered at POU, reduced risk of diarrhoea up to around 50%.”

In the paper

“Public health interventions, such as WASH, are often complex and contain several interacting components, require multiple behaviours and target groups, and are often inherently difficult to randomise or mask, which makes them more likely to be rated as low or very low certainty evidence compared with interventions that can be better controlled, such as clinical interventions.104, 105”

What the sources say

• Not checked yetcites [104] Movsisyan A Melendez-Torres GJ Montgomery P Outcomes in systematic reviews of complex interventions never reached “high” GRADE ratings when compared with those of simple interventions J Clin Epidemiol 78 2016 22 33 27038850 source
• Not checked yetcites [105] Murad MH Almasri J Alsawas M Farah W Grading the quality of evidence in complex interventions: a guide for evidence-based practitioners Evid Based Med 22 2017 20 22 27932400 source

In the paper

“We did not systematically search the grey literature, so we could have missed studies that were not published in peer-reviewed journals.”

In the paper

“Other research suggests that providing water on premises is important for overall wellbeing90 through benefits to quality of life, such as the ability to reallocate time previously used for water collection to income generation or leisure,91 positive health effects (eg, on musculoskeletal disorders),92 reduced labour and calorie expenditure,93 and a potential increase in water quantity for other”

What the sources say

• Not checked yetcites [90] Bisung E Elliott SJ Improvement in access to safe water, household water insecurity, and time savings: a cross-sectional retrospective study in Kenya Soc Sci Med 200 2018 1 8 29355826 source
• Not checked yetcites [91] Whittington D Cook J Valuing changes in time use in low- and middle-income countries J Benefit Cost Anal 10 suppl 1 2019 51 72 32983833 PMC7473062 source
• Not checked yetcites [92] Geere J-A Bartram J Bates L Carrying water may be a major contributor to disability from musculoskeletal disorders in low income countries: a cross-sectional survey in South Africa, Ghana and Vietnam J Glob Health 8 2018 010406 PMC5825974 29497503 source
• Not checked yetcites [93] Chew JF Corlin L Ona F Water source preferences and water quality perceptions among women in the eastern region, Ghana: a grounded theory study Int J Environ Res Public Health 16 2019 e3835 PMC6843409 31614511 source

In the paper

“A previous Cochrane review on drinking water interventions, which was last updated in 2014 and had narrower inclusion criteria than in this review, found similar RRs for water treatment at POU but did not provide pooled estimates for source-based water improvements, piped water to households, or higher water quality supplied on premises.1”

What the sources say

• Not checked yetcites [1] Clasen TF Alexander KT Sinclair D Interventions to improve water quality for preventing diarrhoea Cochrane Database Syst Rev 10 2015 CD004794 PMC4625648 26488938

In the paper

“Of note, the GRADE approach was developed for rating the evidence of health-care interventions.29”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [29] Schünemann HJ Brozek J Guyatt G Oxman AD GRADE handbook: introduction to GRADE handbook https://gdt.gradepro.org/app/handbook/handbook.html#h.w6r7mtvq3mjz 2013

In the paper

“Additionally, there was a potential for exposure misclassification, low compliance and response bias, and high heterogeneity across studies, as well as limitations related to the analysis at study level.”

In the paper

“Furthermore, much of sewered sanitation worldwide is not connected to adequate treatment of waste water, which results in high environmental contamination with faeces and subsequently increased risks of diarrhoeal disease in adjacent communities.102, 103”

What the sources say

• Not checked yetcites [102] Baum R Luh J Bartram J Sanitation: a global estimate of sewerage connections without treatment and the resulting impact on MDG progress Environ Sci Technol 47 2013 1994 2000 23323809 source
• Not checked yetcites [103] Berendes DM Sumner TA Brown JM Safely managed sanitation for all means fecal sludge management for at least 1.8 billion people in low and middle income countries Environ Sci Technol 51 2017 3074 3083 28128924 source

In the paper

“Second, intermittent piped water is a considerable issue in LMICs that affects both water quality and quantity, with hundreds of millions of people estimated to be affected.80”

What the sources say

• Not checked yetcites [80] Kumpel E Nelson KL Intermittent water supply: prevalence, practice, and microbial water quality Environ Sci Technol 50 2016 542 553 26670120 source

In the paper

“GBD 2019 estimated substantially larger reductions in risk of diarrhoea with piped water compared with unimproved water (0·64 [0·56–0·73]), high-quality piped water compared with unimproved water (0·20 [0·09–0·49]), and compared with unimproved untreated water (0·09 [0·04–0·23]), and sewered sanitation or septic tanks compared with unimproved sanitation (0·31 [0·28–0·34]; appendix 2 pp 24–27).106”

What the sources say

• Not checked yetcites [106] GBD 2019 Risk Factors Collaborators Global burden of 87 risk factors in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019 Lancet 396 2020 1223 1249 33069327 PMC7566194

In the paper

“Freeman and colleagues3 found an overall RR of 0·77 (95% CI 0·66–0·91) for the effect of sanitation interventions on risk of diarrhoea in children, which is close to our pooled estimate of all sanitation interventions.”

What the sources say

• Not checked yetcites [3] Freeman MC Garn JV Sclar GD The impact of sanitation on infectious disease and nutritional status: a systematic review and meta-analysis Int J Hyg Environ Health 220 2017 928 949 28602619 source

In the paper

“This meta-analysis presents effect estimates by intervention type and by the respective comparison WASH exposure level, instead of combining results of heterogeneous water, sanitation, and hygiene interventions, and different comparison exposure levels.”

In the paper

“A Cochrane review on handwashing promotion and risk of diarrhoea found similar point estimates for the effects of handwashing promotion on reduction in risk of diarrhoea in communities across LMICs (0·71 [0·62–0·81]) and in day-care facilities and schools in high-income countries (0·70 [0·58–0·85]).2”

What the sources say

• Not checked yetcites [2] Ejemot-Nwadiaro RI Ehiri JE Arikpo D Meremikwu MM Critchley JA Hand-washing promotion for preventing diarrhoea Cochrane Database Syst Rev 12 2021 CD004265 PMC8094449 33539552

In the paper

“A systematic review looking specifically at the association between sewer connection and risk of diarrhoea found an overall RR of 0·70 (0·61–0·79) for all sewer studies and of 0·41 (0·27–0·61) when sanitation service level at baseline or in the comparison group was very poor.14”

What the sources say

• Not checked yetcites [14] Norman G Pedley S Takkouche B Effects of sewerage on diarrhoea and enteric infections: a systematic review and meta-analysis Lancet Infect Dis 10 2010 536 544 20620115 source