Tool 1A - Summary of Evidence
for WASH and Nutrition
Programming
JUNE 2016
The Pathways for WASH
Contribution to
Undernutrition
Pathways linking WASH and Nutrition
There are three direct pathways (related to vicious cycle of infection and
undernutrition)
• Repeated bouts of diarrhea
• Intestinal worm infections
• Environmental enteropathy
Indirect pathways are
• The time spent collecting water and cost of purchasing water
• The time and costs associated with caring for and seeking treatment for
children sick with diseases of poor water and sanitation
• The time spent being sick or fetching water affecting educational
attainment
The Evidence for WASH
Contribution to
Undernutrition
WASH, diarrhea and soil-transmitted
helminth infections
From the Global Burden of Disease study:
Improved WASH could prevent 361 000 diarrheal deaths per
year among children under five years of age, representing
58% of the total diarrhea deaths in this age group.
(Pruss-Ustun et al., 2014)
From meta-analyses:
Improving a range of WASH services and practices in
households reduces the incidence of soil-transmitted
helminth infections by, on average, one third.
(Ziegelbauer et al., 2012; Strunz et al., 2014)
WASH and Nutrition outcomes - 1
Observational studies:
• Open defecation explained 54% of the international variation
in child height, in contrast with GDP, which explained 29%
• The effect was particularly strong for high population density
areas and children under two years
• WHO estimates that half of all cases of undernutrition are
associated with repeated diarrheal or intestinal worm
infections
• Around one-quarter of stunting cases can be attributed to
five or more episodes of diarrhea before the age of two years
• Each episode of diarrhea may increase the possibility of
stunting by 4%
Impact of open defecation on stunting
Sanitation affects stunting
• Sanitation
alone explains
54% of the
international
variation in child
height
• GDP only
explains 29%
• A child’s heightfor-age predicts
adult cognitive
achievement
and productivity
Spears (2012)
chances of stunting
The correlation between episodes
of diarrhea and stunting
diarrhea
Checkley et al. (2008)
WASH and Nutrition outcomes - 2
• There is a strong association between poor WASH practices
and poor Nutrition outcomes but the evidence for the
positive impact of WASH interventions on undernutrition is
more limited
• One systematic review by Cochrane from 2013 found a
small benefit from WASH interventions for the growth in
length and height of children under five, with more
significant impact on children under 24 months
• BUT overall evidence is limited by the lack of published,
rigorous studies, poor quality of the design of studies and
evaluations, poor quality and coverage of interventions, and
conpounding factors challenging the attribution of results
Improving the evidence base –
Randomized, controlled trials underway
• Sanitation Hygiene Infant Nutrition Efficiency (SHINE) Trial
(Zimbabwe) – A cluster-randomized, community-based trial in two
rural districts of Zimbabwe. It will determine the independent and
combined effects of two interventions (improved WASH and
improved infant feeding) on stunting and anemia among children
followed from 12 weeks gestation to 18 months of life.
• WASH benefits (Kenya & Bangladesh) – Two cluster-randomized,
controlled trials to measure the impact of sanitation, water quality,
handwashing and nutrition interventions on child health and
development after two years of intervention in rural Bangladesh and
Kenya. The studies are large in scope, with > 5,000 newborns per
country.
• MapSan (Maputo) – A controlled, before-and-after study of the
health impacts of shared sanitation in a low-income urban setting.
The 12-month follow-up phase on diarrhea, STH, height and weight
in children finishes in January 2017.
The Evidence for WASHNutrition Synergized
Service Delivery
Lessons learned from USAID WASHplus
projects in Mali, Uganda and Bangladesh
 Impact on stunting – programs with integrated WASH
activities show greater impact on the reduction of
stunting that programs with nutrition activities alone
 Planned vs opportunistic integration – WASH is often
added to the nutrition program after it starts and this
makes it more difficult to track the results of integration
 Attribution – challenges in measuring the extent to which
nutritional outcomes are the result of WASH interventions
or joint interventions
Lessons learned from USAID WASHplus
projects in Mali, Uganda and Bangladesh
 Benefits of two-way integration – while two-way integration
appears logical and more collaborative evidence strongly
supports WASH contribution to nutrition outcomes, there is
little evidence to suggest that integrating nutrition into WASH
enhances WASH outcomes
 Targeting scope – Nutrition activities target outreach staff
and caregivers whereas many of the WASH activities target
the whole community
 Adapted sanitation interventions – Traditional WASH
interventions to reduce open defecation may need to be
supplemented with new approaches to break the fecal-oral
transmission cycle from animal feces
Ethiopia: Comparison of communitybased interventions to reduce stunting
 11 villages received either i) Nutrition, ii) Health, iii) WASH or
iv) all 3 interventions over a five-year period
 The WASH group was the only one to show a significant
association between intervention activities and reduced
prevalence of stunting
 The villages receiving all 3 interventions showed the greatest
improvements in access to water
 But … results are not reliable due to the interference of other
factors, especially the quality of programming (the WASH
intervention was led by a strong team leader throughout)
Peri-urban WASH and Nutrition
Project in Bangladesh