WASH Benefits Kenya: A Cluster Randomized Controlled Trial of the Benefits of Sanitation, Water Quality, Handwashing, and Nutrition Interventions on Child Health and Development

Children in resource-poor settings are at risk of multiple episodes of diarrhea, enteric infections, and environmental enteropathy, an inflammatory disorder of the intestines that compromises nutrient absorption (1). In cross-sectional analyses, repeated episodes of diarrhea and chronic environmental enteropathy in early childhood are associated with reduced growth and cognitive function, and impaired school performance which can reduce income later in life (2-8). Although more evidence is needed to establish causal links, repeated episodes of childhood diarrhea and enteric infection may exact a long-run toll, perpetuating a cycle of poverty and ill health.

Infection and inadequate diet are proximate risk factors for undernutrition and early life growth faltering; the two processes likely act reciprocally in a vicious cycle that perpetuates physiologic and metabolic deficits and increases the risk of mortality. Children who exhibit growth faltering are more likely to have deficits in cognitive development and long-term human capital, and are more likely to have children who also suffer from growth deficits - perpetuating the cycle into the next generation.

There are two probable interdependent pathways that link enteric infections to child growth and development. The first pathway includes repeated infections that lead to acute illness or parasitic infection in the first years of life, which increase the risk of stunting and subsequent cognitive deficits in childhood and later in life. The second pathway is through subclinical environmental enteropathy.

There is limited evidence to demonstrate whether or not water quality, sanitation, and handwashing (WASH) interventions can improve measures of environmental enteropathy, child growth and development, and whether nutritional interventions could be enhanced if provided concurrently with WASH interventions. To help fill this evidence gap, the WASH Benefits study will deliver randomized interventions designed to reduce infection and improve nutrition, and will measure intervention effects on child illness, growth and development. WASH Benefits includes two, comparable but standalone trials in Bangladesh and Kenya that are registered under separate protocols.

In Kenya, the study will include approximately 800 clusters, and each cluster will enroll approximately 10 household compounds with pregnant women in their second or third trimester. The study will randomize 100 clusters to each of 6 active intervention arms (water quality, sanitation, handwashing, combined WSH, nutrition, nutrition+WSH), 200 clusters to a double size active control arm, and 100 clusters to a single-sized passive control arm (measurement pending future funding). Children born into the cohort will be followed for 2 years after the intervention, with measurements at 12 and 24 months after intervention delivery. (anticipated age range: 20 - 27 months old at the final measurement). At the 12- and 24-month follow-up visits, the study will collect child anthropometric measurements and caregiver-reported diarrhea. In the final visit the study will administer a test to measure child development outcomes. The study will collect urine, blood, and stool specimens from a subsample of 1,500 children distributed across four arms of the study (Active Control, Combined WSH, Nutrition, Nutrition+WSH) to measure biomarkers of gut function and intestinal parasitic infections at the 12- and 24-month follow-up visits. In addition, the study will collect specimens (blood, stool) from children 18 - 27 months old at baseline who are living in the same compound as target children to test for intestinal parasitic infections.