Peer-reviewed article

Effect of safe water delivery plus water and sanitation hygiene behavior change communication on diarrheal disease prevalence among children under 5 years in a slum setting in Nairobi, Kenya: a quasi-experimental study

Jonathan Izudi, Evans Muchiri, Dennis M Musyoka, Sheillah N. Simiyu, Innocent Kamara Tumwebaze et al. · 28 Oct 2025

Abstract

BACKGROUND: Diarrheal diseases are prevalent among children under five years of age in slum areas. We evaluated the effect of safe water delivery plus water, sanitation, and hygiene (WASH)-Behavior Change Communication (WASH-BCC on diarrheal disease prevalence among children under 5 years in a slum setting in Nairobi, Kenya. METHODS: We designed a quasi-experimental study, with the intervention as safe water delivery plus WASH-BCC. The intervention arm consisted of 2 slum villages that received safe water plus WASH-BCC, while the comparison arm comprised 2 slum villages that did not receive the intervention. The primary outcome was diarrheal disease in a child under five years of age in the past 2 weeks in both study arms, defined as the passage of ≥ 3 watery stools in the past 24 h. Data were collected at the baseline and endline from a random sample of eligible households in the villages. Propensity score weighting was used to achieve similarity in measured covariates between both arms. Binary logistic regression analysis, adjusting for propensity-score weights, was utilized to estimate the causal effect of the intervention, reported as odds ratio (OR) and 95% confidence interval (CI). RESULTS: We analyzed data from 1,876 participants in a 1:1 ratio and found 382 (20.4%) children under five years of age had diarrheal disease at the endline. Diarrheal disease prevalence declined in the intervention villages (33.3% baseline vs. 23.5% endline) but increased in the comparison villages (15.7% baseline vs. 17.5% endline). We found a 31% decline in diarrheal disease in the intervention villages relative to the comparison villages (OR 0.69, 95% CI 0.55-0.86). In a difference-in-differences analysis, the decline was 11.4%. The findings remained robust in a sensitivity analysis. CONCLUSION: The intervention significantly reduced diarrheal disease prevalence in children under five years of age in the slum setting. Therefore, there is a need to expand the intervention to the remaining areas to reduce diarrheal disease morbidity and mortality.