Implications of WASH Benefits trials for water and sanitation
Authors: Diane Coffey, Dean Spears
Journal: The Lancet Global Health (2018)

Results of the WASH Benefits trials in Bangladesh and Kenya have been reported by Stephen Luby and colleagues1Luby SP Rahman M Arnold BF et al.Effects of water quality, sanitation, handwashing, and nutritional interventions on diarrhoea and child growth in rural Bangladesh: a cluster randomised controlled trial.Lancet Glob Health. 2018; 6: e302-e315Summary Full Text Full Text PDF PubMed Scopus (344) Google Scholar and by Clair Null and colleagues,2Null C Stewart CP Pickering AJ et al.Effects of water quality, sanitation, handwashing, and nutritional interventions on diarrhoea and child growth in rural Kenya: a cluster-randomised controlled trial.Lancet Glob Health. 2018; 6: e316-e329Summary Full Text Full Text PDF PubMed Scopus (318) Google Scholar respectively. One group in each study assessed the effect on child height-for-age of "household sanitation upgrades from unimproved to improved latrines" in the child's compound. In both studies, adult latrine use was high at baseline: only about 5% of adults in each setting initially defecated in the open. The trials found that child height was not increased by upgrading sanitation facilities. Global elimination of open defecation by 2030 is a Sustainable Development Goal (SDG). Although the results of the WASH Benefits trials are important for understanding sanitation intervention and similar programmes, we note that the results of these trials do not imply that child health would not be improved by a large transition from open defecation to latrine use, especially in a densely populated area, and that these results are consistent with existing observational data. Based on data from four Demographic and Health Surveys (DHS), the table reports illustrative regressions of child height-for-age on sanitation practices in a child's local neighbourhood, among rural children in Bangladesh (2014), Kenya (2014), and India (2005 and 2015). All regressions include controls for the child's household's wealth quintile.TableChild height and rural sanitation in Demographic and Health SurveysBangladesh (2014)Kenya (2014)India (2005–06)India (2015–16)Linear regressions (dependent variable: child height-for-age)Local improved sanitation (fraction)0·137 (SE 0·102)0·105 (SE 0·0755)−0·0880 (SE 0·113)−0·0903 (SE 0·0547)Local open defecation (fraction)....−0·394 (SE 0·0964)−0·362 (SE 0·0498)Controls for asset quintilesYesYesYesYesNumber of rural children younger than 5 years477712 79426 065171 519Summary statistics for all rural households or childrenOpen defecation (household)8·7%16·6%74·7%54·9%Unimproved sanitation (household)35·6%64·4%76·8%56·8%Height-for-age (child younger than 5 years)−1·617−1·284−1·968−1·590SE for regression coefficients clustered by survey primary sampling unit. Improved sanitation and open defecation fractions are the fraction of households in a child's survey primary sampling unit reporting a sanitation behaviour. Regression constant not reported owing to space. Open table in a new tab SE for regression coefficients clustered by survey primary sampling unit. Improved sanitation and open defecation fractions are the fraction of households in a child's survey primary sampling unit reporting a sanitation behaviour. Regression constant not reported owing to space. In Bangladesh and Kenya, where open defecation is uncommon, the independent variable is the fraction of households in a child's neighbourhood that use improved sanitation rather than unimproved sanitation or open defecation. This neighbourhood-level variable is intended to capture disease externalities. These observational results are consistent with the trial outcome: use of improved latrines is not significantly associated with child height. The coefficients on improved latrine use (reflecting a large linearised difference between 0% and 100% in neighbourhood-level improved latrine use) are less than 0·15 height-for-age SD, the minimal effect size that WASH Benefits was powered to detect. The table also analyses data from two Indian DHS. Unlike in the settings of WASH Benefits, in rural India most people defecate in the open. In both Indian surveys, the fraction of households in a child's neighbourhood that defecate in the open is associated with a large difference in average child height-for-age. The fraction of households that use improved sanitation is not associated with height once open defecation is controlled. Further demographic evidence3Hathi P Haque S Pant L Coffey D Spears D Place and child health: the interaction of population density and sanitation in developing countries.Demography. 2017; 54: 337-360Crossref PubMed Scopus (51) Google Scholar suggests that the health consequences of open defecation are greater where population density is high; if so, children in rural India are at especially high risk. We report grants from the Bill & Melinda Gates Foundation, outside of the submitted work. Effects of water quality, sanitation, handwashing, and nutritional interventions on diarrhoea and child growth in rural Kenya: a cluster-randomised controlled trialBehaviour change messaging combined with technologically simple interventions such as water treatment, household sanitation upgrades from unimproved to improved latrines, and handwashing stations did not reduce childhood diarrhoea or improve growth, even when adherence was at least as high as has been achieved by other programmes. Counselling and supplementation in the nutrition group and combined water, sanitation, handwashing, and nutrition interventions led to small growth benefits, but there was no advantage to integrating water, sanitation, and handwashing with nutrition. Full-Text PDF Open Access