Globally, nearly 3 billion people rely on solid fuels for cooking and heating, the vast majority in low- and middle-income countries (LMICs). The resulting household air pollution (HAP) is the third leading risk factor in the 2010 global burden of disease, accounting for an estimated 4.3 million deaths annually, largely among women and young children. Previous interventions have provided cleaner biomass-based cookstoves but have failed to reduce exposure to levels that produce meaningful health improvements. There have been no large-scale field trials with liquefied petroleum gas (LPG) cookstoves, likely the cleanest scalable intervention.
The aim of this study is to conduct a randomized controlled trial of LPG stove and fuel distribution in 3,200 households in four LMICs (India, Guatemala, Peru, and Rwanda) to deliver rigorous evidence regarding potential health benefits across the lifespan. Each intervention site will recruit 800 pregnant women (aged 18-34 years, 9 - \<20 weeks gestation) and will randomly assign half their households to receive LPG stoves and an 18-month supply of LPG. Control households are anticipated to continue to cook primarily with solid biomass fuels and will receive compensation based on a uniform set of trial-wide principles, customized to each site based on formative research. The mother will be followed along with her child until the child is 1 year old. In households with a second, non-pregnant older adult woman (aged 40 to \<80 years) the researchers will also enroll and follow her during the 18-month follow-up period in order to assess cardiopulmonary, metabolic, and cancer outcomes. To optimize intervention use, the researchers will implement behavior change strategies. This study will assess cookstove use, conduct repeated personal exposure assessments to HAP (PM2.5, black carbon, carbon monoxide), and collect dried blood spots and urinary samples for biomarker analysis and biospecimen storage on all participants at multiple time points. The primary outcomes are low birth weight, severe pneumonia incidence, and stunting of the child, and systolic blood pressure in the older adult woman.
This study will address the following specific aims: (1) using an intent-to-treat analysis, determine the effect of a randomized LPG stove and fuel intervention on health in four diverse LMIC populations using a common protocol; (2) determine the exposure-response relationships for HAP and health outcomes; and (3) determine relationships between LPG intervention and both targeted and exploratory biomarkers of exposure/health effects.
This study will provide evidence, including costs and implementation strategies, to inform national and global policies on scaling up LPG stoves among vulnerable populations. Ultimately, this will facilitate deeper policy-level discussions as well as identify requirements for initiating and sustaining HAP interventions globally.
The intervention delivery occurred until the child was one year of age. The researchers will continue to follow participants in India, Guatemala and Rwanda until the child is 5 years old to assess the longer-term effects of the intervention. Previous evidence suggests that the benefits of reduced exposure during the first, critical year of development will continue even if the intervention ends. The researchers will continue using methods employed during the HAPIN trial period. The HAPIN trial provides a unique context in which to address these questions, particularly given the successful intervention and exposure reduction. Participants are well-characterized and health and exposures to air pollution are being documented. Critically, because of its experimental design of the trial, continued follow-up of the cohort will provide rigorous causal inferences about the effects of this 500-day intervention over the most important period of early childhood development.
