WASH alone cannot prevent childhood linear growth faltering
Authors: Kenneth M Maleta, Mark J Manary
Journal: The Lancet Global Health (2018)

Prevention and treatment of childhood stunting, which is a pervasive problem in most low-income and middle-income countries, remain a challenge. Stunting arises from multifactorial biological, social, and environmental causes that are often interlinked at various levels.1Cumming O Cairncross S Can water, sanitation and hygiene help eliminate stunting? Current evidence and policy implications.Matern Child Nutr. 2016; 12: 91-105Crossref PubMed Scopus (143) Google Scholar Despite a worldwide reduction in the prevalence of stunting, as many as 165 million children younger than 5 years remain stunted, most of whom are in low-income and middle-income countries. Children who are stunted have increased mortality, impaired cognitive development, and reduced incomes as adults compared with healthy children.2Black RE Victora CG Walker SP et al.Maternal and child undernutrition and overweight in low-income and middle-income countries.Lancet. 2013; 382: 427-451Summary Full Text Full Text PDF PubMed Scopus (4259) Google Scholar In The Lancet Global Health, Jean Humphrey and colleagues present the primary results of SHINE, a disciplined, highly committed, evidenced-based trial3Humphrey JH Mbuya MNN Ntozini R Independent and combined effects of improved water, sanitation, and hygiene, and improved complementary feeding, on child stunting and anaemia in rural Zimbabwe: a cluster-randomised trial.Lancet Glob Health. 2019; 7: e132-e147Summary Full Text Full Text PDF PubMed Scopus (223) Google Scholar that addressed the effect on childhood stunting of a comprehensive package of water, sanitation, and hygiene (WASH) interventions—specifically, provision of an improved pit latrine, two handwashing stations, liquid soap, chlorine for sanitisation of drinking water, and segregated play spaces for infants and toddlers—in rural Zimbabwe. In recognition of the fact that a poor-quality diet contributes to stunting, the investigators used a 2 × 2 factorial design in which participants were randomised (1:1:1:1) to receive either complementary food, WASH interventions, both, or standard of care. The interventions were delivered in a reliable and consistent manner. For these households and the many research staff working on SHINE, the trial represented a multiyear, defining endeavour. Thus, there are important lessons to learn. Overall, the results of SHINE showed that a dietary supplement fortified with micronutrients improved mean length-for-age Z score by 0·16 (95% CI 0·08–0·23) compared with the other interventions. The WASH intervention had no effect on length-for-age Z scores, either alone or in combination with the infant and young child feeding intervention. We applaud Humphrey and colleagues for stating their findings with confidence, and policy makers and programme implementers should take note, because a well done negative trial should be used to plan and guide their efforts. Humphrey and colleagues propose three possible reasons for the findings: the hypothesis that WASH has an independent effect on linear growth was incorrect, the WASH interventions used were not effective enough to facilitate linear growth and reduce diarrhoea, or the trial did not address intergenerational prenatal determinants of stunting. This Article and two previous papers4Luby 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, 5Null 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 provide the most robust evidence to date of the limited independent effect on stunting of WASH interventions that are being implemented in most low-income and middle-income. These findings raise the question of whether investment in these interventions is worthwhile. WASH has both health and non-health outcomes, all of which contribute to maternal and child wellbeing.1Cumming O Cairncross S Can water, sanitation and hygiene help eliminate stunting? Current evidence and policy implications.Matern Child Nutr. 2016; 12: 91-105Crossref PubMed Scopus (143) Google Scholar SHINE reported high fidelity of intervention delivery and qualitative and quantitative measures to assess adherence (availability of the technology, presumed use, reductions in open defecation, and reduction in contact with animal faeces and childhood geophagia). Unfortunately, the WASH intervention did not result in sustained behavioural changes with regard to handwashing or open defecation at the community level, both of which could explain the findings. According to Rothman's sufficient-cause model,6Rothman KJ Causes, 1976.Am J Epidemiol. 1995; 141: 90-95Crossref PubMed Scopus (41) Google Scholar WASH could well be an important component of interventions to reduce stunting, but not sufficient to reduce stunting in isolation. To this end, the intermediate outcomes reported (diarrhoeal morbidity) and not reported (environmental enteric dysfunction) are important. Although WASH interventions did not reduce diarrhoea in Kenya5Null 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 and Zimbabwe,3Humphrey JH Mbuya MNN Ntozini R Independent and combined effects of improved water, sanitation, and hygiene, and improved complementary feeding, on child stunting and anaemia in rural Zimbabwe: a cluster-randomised trial.Lancet Glob Health. 2019; 7: e132-e147Summary Full Text Full Text PDF PubMed Scopus (223) Google Scholar they did in Bangladesh.4Luby 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 Component causes are context-specific.6Rothman KJ Causes, 1976.Am J Epidemiol. 1995; 141: 90-95Crossref PubMed Scopus (41) Google Scholar, 7Manary M It's the context!.Am J Clin Nutr. 2015; 101: 693-694Crossref PubMed Scopus (9) Google Scholar The absence of a growth or clinical morbidity response in SHINE does not mean that WASH is totally unimportant as development agencies and agents strive to achieve the Sustainable Development Goals, but it should cause such agencies and agents to carefully reconsider their approaches. We declare no competing interests. Independent and combined effects of improved water, sanitation, and hygiene, and improved complementary feeding, on child stunting and anaemia in rural Zimbabwe: a cluster-randomised trialHousehold-level elementary WASH interventions implemented in rural areas in low-income countries are unlikely to reduce stunting or anaemia and might not reduce diarrhoea. Implementation of these WASH interventions in combination with IYCF interventions is unlikely to reduce stunting or anaemia more than implementation of IYCF alone. Full-Text PDF Open Access