Research Article: Effects of a large-scale distribution of water filters and natural draft rocket-style cookstoves on diarrhea and acute respiratory infection: A cluster-randomized controlled trial in Western Province, Rwanda

Date Published: June 3, 2019

Publisher: Public Library of Science

Author(s): Miles A. Kirby, Corey L. Nagel, Ghislaine Rosa, Laura D. Zambrano, Sanctus Musafiri, Jean de Dieu Ngirabega, Evan A. Thomas, Thomas Clasen, James K Tumwine

Abstract: BackgroundUnsafe drinking water and household air pollution (HAP) are major causes of morbidity and mortality among children under 5 in low and middle-income countries. Household water filters and higher-efficiency biomass-burning cookstoves have been widely promoted to improve water quality and reduce fuel use, but there is limited evidence of their health effects when delivered programmatically at scale.Methods and findingsIn a large-scale program in Western Province, Rwanda, water filters and portable biomass-burning natural draft rocket-style cookstoves were distributed between September and December 2014 and promoted to over 101,000 households in the poorest economic quartile in 72 (of 96) randomly selected sectors in Western Province. To assess the effects of the intervention, between August and December, 2014, we enrolled 1,582 households that included a child under 4 years from 174 randomly selected village-sized clusters, half from intervention sectors and half from nonintervention sectors. At baseline, 76% of households relied primarily on an improved source for drinking water (piped, borehole, protected spring/well, or rainwater) and over 99% cooked primarily on traditional biomass-burning stoves. We conducted follow-up at 3 time-points between February 2015 and March 2016 to assess reported diarrhea and acute respiratory infections (ARIs) among children <5 years in the preceding 7 days (primary outcomes) and patterns of intervention use, drinking water quality, and air quality. The intervention reduced the prevalence of reported child diarrhea by 29% (prevalence ratio [PR] 0.71, 95% confidence interval [CI] 0.59–0.87, p = 0.001) and reported child ARI by 25% (PR 0.75, 95% CI 0.60–0.93, p = 0.009). Overall, more than 62% of households were observed to have water in their filters at follow-up, while 65% reported using the intervention stove every day, and 55% reported using it primarily outdoors. Use of both the intervention filter and intervention stove decreased throughout follow-up, while reported traditional stove use increased. The intervention reduced the prevalence of households with detectable fecal contamination in drinking water samples by 38% (PR 0.62, 95% CI 0.57–0.68, p < 0.0001) but had no significant impact on 48-hour personal exposure to log-transformed fine particulate matter (PM2.5) concentrations among cooks (β = −0.089, p = 0.486) or children (β = −0.228, p = 0.127). The main limitations of this trial include the unblinded nature of the intervention, limited PM2.5 exposure measurement, and a reliance on reported intervention use and reported health outcomes.ConclusionsOur findings indicate that the intervention improved household drinking water quality and reduced caregiver-reported diarrhea among children <5 years. It also reduced caregiver-reported ARI despite no evidence of improved air quality. Further research is necessary to ascertain longer-term intervention use and benefits and to explore the potential synergistic effects between diarrhea and ARI.Trial registrationClinical NCT02239250.

Partial Text: Unsafe drinking water and household air pollution (HAP) are major causes of morbidity and mortality worldwide, particularly among young children in low-income countries [1]. Fecal contamination of drinking water contributes to diarrheal disease, the third leading cause of mortality in low-income countries, with an estimated 1.3 million deaths in 2015 [2]. An estimated 1.8 billion people worldwide lack access to safe drinking water, more than a third of whom rely primarily on water supplies such as shallow open wells and surface sources that are often highly contaminated with human and animal feces [3]. Cooking indoors with solid biomass fuels, such as wood, charcoal, and crop residues—the major source of HAP—is practiced by an estimated 3 billion people, primarily in low-income settings [4]. There is evidence linking the use of solid fuels to a wide range of health impacts, with the heaviest burden occurring among women and children, who spend the most time near cooking activities and experience the highest exposures [5].

We assessed the impact of a large-scale program in Rwanda that provided and promoted the use of a tabletop gravity-based water filter and portable natural draft “rocket stove” to households in the poorest socioeconomic quartile. Ten to 17 months after delivery of the intervention, most households had the filter and reported using it, and approximately half of households possessed filters that were observed to contain water. However, we recorded evidence of decreasing use over time, and consumption of untreated water was reported among some respondents and children. The intervention was effective in improving household drinking water quality and reducing the risk of reported diarrhea in children <5 years old by 29% (95% CI 13%–41%). Notably, the intervention reduced reported diarrhea-related child visits to health facilities within the previous week, a possible indication of effects on severe episodes [37]. A majority of households reported using the intervention stove 10 to 17 months after delivery, although reported use decreased over time, and traditional stove use persisted and increased over time. The intervention reduced the risk of reported ARI by 25% (95% CI, 7%–40%), as well as reported visits to CHWs by 38% despite the lack of an effect on the household primary cook’s or child’s exposure to PM2.5. Source:


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