Study Design and Population

The WASH Benefits Bangladesh study measured the impact of WSH and nutrition interventions on child growth, development, and parasitic infection (ClinicalTrials.gov, NCC01590095) [22, 24, 25, 29, 30]. Intervention arms included drinking water treatment, sanitation, handwashing, combined WSH, nutrition, and combined N+WSH. This analysis includes children enrolled in the environmental enteric dysfunction substudy, which was a subsample of clusters from the WSH, nutrition, N+WSH, and control arms (in a 1:1:1:1 ratio) [31, 32]. Interventions were delivered while mothers were pregnant, so children were exposed to interventions from birth; a detailed description of interventions has been provided previously [22]. In brief, the WSH intervention consisted of chlorine tablets and a safe drinking water storage vessel; a dual-pit latrine with a water seal, child potties, and hoes for feces disposal; and handwashing stations (including detergent soap with dispensers) near the latrine and kitchen. The nutrition intervention consisted of age-appropriate infant feeding recommendations plus lipid-based nutrient supplements twice daily from age 6 months to 24 months. The N+WSH intervention combined the WSH and nutrition packages. Behavior change messaging was delivered 6 times per month to intervention households, which resulted in high adherence [22]. Rotavirus vaccination had not been implemented in Bangladesh at the time of the study.

Although enteropathogen prevalence tends to increase with age over the first 2 years of life, the importance of early pathogen carriage on later health outcomes (eg, stunting and cognitive deficits [5, 33]) motivated us to evaluate children at a younger age (14 ± 2 months) than the parasite studies (30 ± 2 months) [31, 32]. Written informed consent was obtained from parents of all children. The trial was approved by human subjects committees at the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b; PR-11063), the University of California, Berkeley (2011-09-3652), and Stanford University (25863).