Special Epidemiology Seminar - "Does drinking water from improved sources lead to waterborne disease in low-income countries? Evidence from impact evaluations of infrastructure improvement in urban India and household water treatment in rural Bangladesh"
Ayse Ercumen, PhD
Project Scientist, University of California, Berkeley
Does drinking water from improved sources lead to waterborne disease in low-income countries? Evidence from impact evaluations of infrastructure improvement in urban India and household water treatment in rural Bangladesh
ALL ARE WELCOME
Abstract:
Epidemiologists are increasingly involved in leading impact evaluations of large-scale public health interventions in order to assess whether health benefits can be demonstrated when subjected to rigorous measurement. I will present epidemiologic evidence from two large impact evaluations focused on drinking water quality and access in low-income countries.
In Hubli-Dharwad, India, our team studied an infrastructure upgrade from intermittent to continuous delivery of piped water, in which 10% of the city was switched to continuous water supply. Using genetic matching, a multivariate matching technique (Diamond and Sekhon, Rev Econ Stat, 2013) with the potential for broad application in epidemiologic studies, we constructed a matched cohort of 4,000 households and followed them longitudinally to record waterborne illness, child mortality and weight-for-age. We found no overall impact on general diarrheal symptoms and weight-for-age but continuous supply was associated both with reduced bloody diarrhea in low-income households and reduced typhoid fever incidence.
I will also present evidence from a cluster-randomized controlled trial in rural Bangladesh, which we designed to measure the diarrhea burden associated with fecal contamination of tubewell water at the point of source versus point of use. We randomly assigned 1,800 households into one of three arms: drinking water treatment with chlorine plus safe storage, safe storage alone and control. Both interventions significantly reduced diarrhea in young children. Given safe storage, there was no added health benefit from chlorination, suggesting that groundwater in this setting becomes contaminated predominantly during storage in homes and safe storage is sufficient to reduce child diarrhea.
These findings highlight deteriorations in water quality associated with deficiencies in the distribution and handling of drinking water from sources typically categorized as improved. Efforts to reduce the global burden of waterborne disease should place emphasis on interventions proven to reduce contamination at each step leading from the water source to the point of consumption, including the distribution system and household storage containers.
Objectives:
1) Epidemiological study designs to assess the health impact of water, sanitation and hygiene improvements in low-income countries
2) Use of multivariate matching to study non-randomized preexisting interventions
3) Negative control exposures and outcomes to detect measurement bias and confounding in randomized trials and observational studies
Bio:
Ayse Ercumen is a research scientist in the Division of Epidemiology at the UC Berkeley School of Public Health. Dr. Ercumen received her Ph.D. in Epidemiology and her M.P.H. in Epidemiology and Biostatistics from UC Berkeley, and has an M.S. in Environmental Engineering from UC Berkeley and a B.S. in the same field from Massachusetts Institute of Technology. Her research interests include health impacts of urban water infrastructure improvements and low-cost water treatment and sanitation technologies for low-income countries. She has conducted research in Bangladesh and India, including large-scale health impact evaluations and randomized controlled trials, and she has taught advanced-level epidemiologic methods and impact evaluation courses at UC Berkeley.
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