Topical Area: Global Nutrition
Objectives : We recently completed 3 efficacy trials (Bangladesh, Kenya, Zimbabwe) testing the independent and combined effects of improved complementary feeding (CF) and intensive household water quality, sanitation,and hygiene (WASH) on child diarrhea and length-for-age-Z-score (LAZ) at 18 to 24 mo. Intervention uptake was high. In all three trials: CF increased LAZ but WASH had no effect on LAZ. WASH reduced diarrhea in Bangladesh but not in Kenya or Zimbabwe. We present a synthesis of trial findings and their implications.
Methods : Reviews of the literature and reanalyses of trial data were conducted.
Results : WASH and stunting: Copious observational studies have demonstrated a strong association between household-level WASH and child LAZ. We conducted an observational anlaysis (nested birth cohort) from our control arms. In adjusted analyses of all three trials, having an improved latrine when the pregnant woman was enrolled was associated with ~0.2LAZ increase in her child at 18-24 mo. The frequently reported association between household WASH indicators and child growth may be confounded and drawing causal inferance misguided.
WASH and diarrhea: Promoters visited intervention households 6 times per month in Bangladesh and monthly in Kenya and Zimbabwe. We conducted a systematic literature review: virtually all evidence that household water chlorination and handwashing reduce diarrhea comes from studies with daily to fortnightly intervention contact. In studies with follow-up after the trial ending, behaviors steeply declined and the effect on child diarrhea disappeared. Household water chlorination and handwashing promotion implemented through sporadic message delivery may not reduce child diarrhea.
Enteropathogen transmission: Despite achieving substantial contrast between WASH and non-WASH households, children in the WASH arms still experienced high enteropathogen transmission, illustrating the recalcitrance of pervasive fecal contamination in rural low-income communities to even intense intervention.
Conclusions : Household WASH interventions are unlikely to reduce child stunting and may not reduce child diarrhea. We call for substantial investment in research to identify and in programming to deliver much more efficacious interventions.
Funding Sources : Bill & Melinda Gates Foundation, USAID, DFID/UKAID, Wellcome Trust
Johns Hopkins University
Civil and Environmental Engineering, Tufts University
Mathmatica Policy Research
Johns Hopkins Bloomberg School of Public Health
Ministry of Health and Child Welfare
School of Public Health, University of California Berkeley
Queen Mary University of London
Program in International and Community Nutrition, University of California, Davis
Johns Hopkins School of Public Health