About the HAPIN Trial

India Stove Picture
Photo Credit: Naveen Puttawasmy 

The Problem

More than 3 billion people, the vast majority in low- and middle-income countries, cook on open fires and traditional stoves using solid fuels such as wood, dung, coal, charcoal and agricultural crop waste—a number that has not changed significantly in the last three decades (HEI 2020). Exposure to the resulting household air pollution (HAP) is a leading risk facing low- and middle-income (LMIC) populations, accounting for an estimated 2.3 million premature deaths annually and 91.5 million disability-adjusted life years (Bennitt 2021).  Exposure to HAP is associated with pediatric acute lower respiratory infections, pneumonia, tuberculosis, chronic lung disease, cardiovascular disease, lung cancer and other health disorders (Lee 2020). 

The HAPIN Trial

HAPIN was a randomized controlled trial of liquefied petroleum gas (LPG) stove and fuel distribution in 3,200 households in four countries. The research team established trial sites in Guatemala, India, Peru, and Rwanda that each recruited 800 pregnant women, their 800 infants, and approximately 120 older adult women into the study. Half of the participating households were randomly assigned to receive a LPG cookstove and fuel, and the other half served as controls using their customary cooking practices. Participating households were followed for 18 months with extensive monitoring of stove use and personal exposure to household air pollution, as well as extensive assessments of health outcomes including preterm birth, birth weight, growth and respiratory infections in children and respiratory function, blood pressure, inflammation, and other indicators of heart disease in adults. For further information on the pre-specified outcomes of the trial, it is registered on ClinicalTrials.gov as NCT02944682. For a full description of the methods, overall studybiomarker, and exposure and stove use assessment protocol papers have all been published.

The first papers on study outcomes have been published, on exposure reduction and birth weight. See the Publications tab for all of the HAPIN articles that have been published to-date. 

The trial will provide compelling, robust evidence on the effects of a LPG cookstove and fuel intervention on reducing exposure to household air pollution and on child health and development as well as adult chronic disease. These data are urgently needed to inform policies on the health gains that can be obtained by scaling up LPG stoves or other interventions to reduce household air pollution among vulnerable populations. 

The HAPIN trial is funded by the National Institutes of Health (NIH) and the Bill & Melinda Gates Foundation. Participating NIH components are the National Heart, Lung, and Blood Institute, the National Cancer Institute, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute of Environmental Health Sciences, the NIH Common Fund of the NIH Office of the Director, and the Fogarty International Center.  The Global LPG Partnership provides expert advice to the consortium. 


Health Effects Institute. The State of Global Air 2020 (Special Report). Boston, MA-Health Effects Institute: 2020. https://www.stateofglobalair.org/ 

Bennitt FB, Wozniak SS, Causey K, Burkart K, Brauer M. Estimating disease burden attributable to household air pollution: new methods within the Global Burden of Disease Study. Lancet Global Health 2021;9:S18. https://doi.org/10.1016/S2214-109X(21)00126-1

Lee KK, Bing R, Kiang J, et al. Adverse health effects associated with household air pollution: a systematic review, meta-analysis, and burden estimation study. Lancet Global Health 2020;8(11):e1427–34. https://doi.org/10.1016/S2214-109X(20)30343-0