# Examining the effect of neighborhood sanitation coverage on childhood diarrheal disease in rural Bangladesh

## TL;DR

This study shows that better sanitation in a neighborhood can significantly reduce childhood diarrhea in rural Bangladesh.

## Contribution

The study introduces a new metric, NSFE, to quantify neighborhood sanitation's impact on fecal exposure and diarrheal disease.

## Key findings

- Diarrheal prevalence was 3.6 times higher in compounds with the highest NSFE compared to the lowest.
- Two-thirds of the NSFE-diarrhea association was concentrated in the top 10% of NSFE values.
- Improving all neighbors' latrines could eliminate 15.5% of childhood diarrhea in the study area.

## Abstract

Neighborhood-level sanitation coverage may offer significant indirect protection against diarrheal disease, an observation that has been supported by several studies.

We analyzed the protective effect of neighborhood sanitation coverage using harmonized data from two studies: a randomized control trial (RCT) examining the effectiveness of improved compound-level sanitation and an observational study that collected information on compounds within 100 meters of the RCT study compounds. We developed the Neighborhood Sanitation & Fecal Exposure (NSFE) metric, which estimates the fecal contamination at a study compound based on the demographic and sanitation characteristics of the neighborhood. NSFE is a function of the number of individuals and latrine quality at surrounding compounds, the distance to neighboring compounds, and the effectiveness of hygienic and unhygienic latrines relative to open defecation. We modeled the relationship between NSFE and childhood diarrheal prevalence within RCT study compounds. Finally, we examined counterfactual scenarios to understand how much of the observed diarrheal burden was attributable to neighbors’ latrine quality.

We estimated a 3.6-fold increase in diarrheal prevalence between compounds with the highest and lowest NSFE, with about two-thirds of this association concentrated in compounds between the 90th and 100th percentile of NSFE values. In counterfactual scenarios, we estimate that 15.5% of the entire diarrheal disease burden in children living in the study compounds would be eliminated if all neighboring compounds had high-quality latrines.

Community effects associated with neighborhood sanitation coverage are important drivers of diarrheal disease and should be considered in future designs of sanitation interventions. Our findings support the importance of universal basic sanitation as a target for United Nations Sustainable Development Goal 6.