Analyzing Sanitation and Population Density: a Multi-Country Review

Research Overview

This study is a desk review of existing data, based on Demographic and Health Survey (DHS), census, and World Bank Water and Sanitation Program data. The purpose of the study is to more fully characterize the relationship between sanitation, population density, and fecal-associated health problems.  

Location

Global

Research Objectives

• Document and compare risk of diarrheal disease and soil-transmitted helminth (STH) infections in high vs. low density settings
• Determine and compare the effect of sanitation coverage on risk of diarrheal disease and STH infection in high vs. low density settings
• Determine if and how sanitation coverage influences disease transmission pathways in high vs. low density settings

Study Approach

In an effort to explore the links between population density, open defecation and child health outcomes, r.i.c.e. conducted an analysis of Demographic and Health Survey (DHS) data from 68 countries and a separate analysis of more detailed survey data from Bangladesh.  The multi-country review included an analysis of 172 DHS to test for external validity while the more detailed data from Bangladesh was used to assess the strength of the causal relationship between population density, open defecation and child health outcomes.  In both analyses researchers utilized logistic regression to model the hypothesized interaction between population density, open defecation and the relationship to child health outcomes.

Lessons Learned

In the analysis of DHS data researchers found an association between population density, open defecation and infant mortality and child height.  Specifically, infant mortality tended to increase and child height tended to decrease in areas of higher population density that also had higher rates of open defecation.  The data demonstrated that given the same amount of open defecation the negative effect on child health outcomes is doubled in areas of high population density compared to areas of low population density.

Analysis of the Bangladesh dataset allowed researchers to examine this trend in greater depth with finer detail.  This data showed similar patterns of association.  Accounting for controls in both models researchers found the interaction between open defecation and population density uniquely associated with adverse child health outcomes.

Research into Action

This research has important implications for policy makers and funders in the water, sanitation and hygiene space.  By demonstrating the open defecation is associated with greater adverse health outcomes in densely populated areas researchers have shown the need to focus investments and attention on improving sanitation conditions in places of relatively greater population density.

A peer-reviewed paper on the full study is forthcoming.  Additionally the Principal Investigator, Dean Spears, has been quoted in a New York Times article discussing the sanitation situation in India.  Researchers plan to disseminate these findings in local and international policy forums and debates in an effort to inform efficient and effective investment strategies for governments, individuals and donors.

Research Partners

r.i.c.e. (research institute for compassionate economics)

Principal Investigator: Dean Spears, PhD

Project Status