Cluster-randomised controlled trials of individual and combined water, sanitation, hygiene and nutritional interventions in rural Bangladesh and Kenya: the WASH Benefits study design and rationale

Benjamin F Arnold, Clair Null, Stephen P Luby, Leanne Unicomb, Christine P Stewart, Kathryn G Dewey, Tahmeed Ahmed, Sania Ashraf, Garret Christensen, Thomas Clasen, Holly N Dentz, Lia C H Fernald, Rashidul Haque, Alan E Hubbard, Patricia Kariger, Elli Leontsini, Audrie Lin, Sammy M Njenga, Amy J Pickering, Pavani K Ram, Fahmida Tofail, Peter J Winch, John M Colford Jr, Benjamin F Arnold, Clair Null, Stephen P Luby, Leanne Unicomb, Christine P Stewart, Kathryn G Dewey, Tahmeed Ahmed, Sania Ashraf, Garret Christensen, Thomas Clasen, Holly N Dentz, Lia C H Fernald, Rashidul Haque, Alan E Hubbard, Patricia Kariger, Elli Leontsini, Audrie Lin, Sammy M Njenga, Amy J Pickering, Pavani K Ram, Fahmida Tofail, Peter J Winch, John M Colford Jr

Abstract

Introduction: Enteric infections are common during the first years of life in low-income countries and contribute to growth faltering with long-term impairment of health and development. Water quality, sanitation, handwashing and nutritional interventions can independently reduce enteric infections and growth faltering. There is little evidence that directly compares the effects of these individual and combined interventions on diarrhoea and growth when delivered to infants and young children. The objective of the WASH Benefits study is to help fill this knowledge gap.

Methods and analysis: WASH Benefits includes two cluster-randomised trials to assess improvements in water quality, sanitation, handwashing and child nutrition-alone and in combination-to rural households with pregnant women in Kenya and Bangladesh. Geographically matched clusters (groups of household compounds in Bangladesh and villages in Kenya) will be randomised to one of six intervention arms or control. Intervention arms include water quality, sanitation, handwashing, nutrition, combined water+sanitation+handwashing (WSH) and WSH+nutrition. The studies will enrol newborn children (N=5760 in Bangladesh and N=8000 in Kenya) and measure outcomes at 12 and 24 months after intervention delivery. Primary outcomes include child length-for-age Z-scores and caregiver-reported diarrhoea. Secondary outcomes include stunting prevalence, markers of environmental enteropathy and child development scores (verbal, motor and personal/social). We will estimate unadjusted and adjusted intention-to-treat effects using semiparametric estimators and permutation tests.

Ethics and dissemination: Study protocols have been reviewed and approved by human subjects review boards at the University of California, Berkeley, Stanford University, the International Centre for Diarrheal Disease Research, Bangladesh, the Kenya Medical Research Institute, and Innovations for Poverty Action. Independent data safety monitoring boards in each country oversee the trials. This study is funded by a grant from the Bill & Melinda Gates Foundation to the University of California, Berkeley.

Registration: Trial registration identifiers (http://www.clinicaltrials.gov): NCT01590095 (Bangladesh), NCT01704105 (Kenya).

Keywords: Drinking Water; Handwashing; Sanitation.

Figures

Figure 1
Figure 1
Summary of the overall study design in both countries, including cluster and target child enrolment in each arm. Growth and diarrhoea measurements will take place at 15 and 27 months following enrolment, which corresponds to 12 and 24 months following initial intervention delivery due to a 3-month lag between enrolment and intervention implementation. C, control; H, improved handwashing; N, improved nutrition; S, improved sanitation; W, improved water quality; WSH, combined improvements in water quality, sanitation and handwashing; WSH+N, combined improvements in water quality, sanitation, handwashing and nutrition.
Figure 2
Figure 2
Summary of EE subsample in both countries, including cluster and target child enrolment in each arm. The EE subsample includes an equal number of clusters and target children from four arms of the study. C, control; EE, environmental enteropathy; H, improved handwashing; N, improved nutrition; S, improved sanitation; W, improved water quality; WSH, combined improvements in water quality, sanitation and handwashing; WSH+N, combined improvements in water quality, sanitation, handwashing and nutrition.
Figure 3
Figure 3
Summary of enteric parasite measurement in both countries, including cluster and target child enrolment in each arm. At enrolment stool specimens will be collected from an older sibling aged 18–27 months if present and will be tested for protozoan infections. At the final measurement, specimens will be collected from the same older siblings plus seven target children per cluster in each country, and analysed for protozoan infections and soil-transmitted helminth infections. C, control; EE, environmental enteropathy; H, improved handwashing; N, improved nutrition; S, improved sanitation; W, improved water quality; WSH, combined improvements in water quality, sanitation and handwashing; WSH+N, combined improvements in water quality, sanitation, handwashing and nutrition.

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