Household Air Pollution and Health: A Multi-country LPG Intervention Trial

Overview

This study is a randomized controlled trial of liquefied petroleum gas (LPG) stove and fuel distribution in 3,200 households in four countries (India, Guatemala, Peru, and Rwanda). Following a common protocol, 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. The researchers estimate that 15% of households will have a second, non-pregnant older adult woman (aged 40 to <80 years) who will also be enrolled at baseline and followed during the 18-month follow-up period. To optimize intervention use, the researchers will implement behavior change strategies informed by previous experiences and formative research in Year 1. This study will assess cookstove use, conduct repeated personal exposure assessments of household air pollution, and collect dried blood spots and urinary samples for biomarker analysis and biospecimen storage. The primary outcomes are low birth weight, severe pneumonia incidence, and stunting of the child, and blood pressure in the older adult woman. Secondary outcomes include preterm birth and development in the child, maternal blood pressure during pregnancy, and endothelial function, respiratory impairment, atherosclerosis, carcinogenic metabolites, and quality of life in the older adult woman.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Prevention
    • Masking: None (Open Label)
  • Study Primary Completion Date: August 2021

Detailed Description

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 blood pressure in the older adult woman. Secondary outcomes include preterm birth and development in the child, maternal blood pressure during pregnancy, and endothelial function, respiratory impairment, atherosclerosis, carcinogenic metabolites, and quality of life 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.

Interventions

  • Other: Liquefied petroleum gas (LPG) cookstove
    • The intervention consists of a high-quality locally-available liquefied petroleum gas (LPG) stove having at least two burners, a continuous supply of LPG fuel for 18 months, and the promotion of stove use on an exclusive basis for cooking. The intervention will be provided free of charge to all intervention households upon enrollment. On a weekly basis, study staff will examine stove condition, perform any repairs necessary, and measure and record weight of LPG tanks in order to anticipate need for refills.

Arms, Groups and Cohorts

  • Experimental: Liquefied petroleum gas cookstove
    • Participants randomized to the experimental arm will receive a liquefied petroleum gas (LPG) cookstove and 18-month supply of LPG.
  • No Intervention: Control
    • Participants in the control group will not receive a liquefied petroleum gas (LPG) stove and will continue using traditional cooking methods (open fire or traditional stoves), or the cooking method of their choice. Control households will receive compensation based on a uniform set of trial-wide principles, customized to each site based on formative research.

Clinical Trial Outcome Measures

Primary Measures

  • Birth weight
    • Time Frame: Up to 5 months (within 24 hours of birth, 3-5 months post randomization)
    • Newborn weight will be assessed by a trained nurse or health worker at the <24-hour visit. Infants will be weighed naked or in a pre-weighed blanket. Weight will measured to the nearest 10 g using a digital electronic scale. Calibration of scales and infantometers, using standard weight and height measures, will be done at the start of each measurement session.
  • Incidence of HAPIN Severe Pneumonia
    • Time Frame: Up to 12 months after birth
    • The number of times a child has severe pneumonia during the first 1 year of life will be assessed. HAPIN pneumonia criteria are adapted from the WHO (2014) and there are 3 algorithms for HAPIN case criteria: 1) the presence of cough or difficult breathing and at least 1 general danger sign plus pneumonia on lung imaging (i.e., lung ultrasound or chest x-ray), or 2) the presence of cough or difficult breathing and hypoxemia (measured either via pulse oximetry (SpO2), or observing a child requiring advanced respiratory support (i.e., intubation and mechanical ventilation, non-invasive ventilation with continuous or bi-level positive airway pressure support, or high-flow nasal cannula oxygen), or 3) children who die prior to evaluation but have pneumonia by verbal autopsy.
  • Length-for-age z-score
    • Time Frame: 12 months after birth
    • The primary outcome measured is linear growth failure, or stunting, at one year of age. Infant length will be assessed quarterly, until the child is 12 months old. Stunting will be assessed using height-for-age z-scores (HAZ) based on the 2006 World Health Organization (WHO) Child Growth Standards. Stunting is defined as HAZ <-2 standard deviations (SD) below the median z-score.
  • Blood pressure
    • Time Frame: Up to 18 months
    • Blood pressure will be assessed in the older adult women in the intervention and control arms using automatic sphygmomanometers (Omron HEM-907XL; Osaka, Japan). The study team will use the procedures adapted from previously validated methods and cardiovascular outcome studies, following recommendations for the American Heart Association and the European Society of Hypertension.

Secondary Measures

  • Maternal blood pressure
    • Time Frame: Up to 5 months
    • Blood pressure will be assessed in the pregnant women in the intervention and control arms using automatic sphygmomanometers (OMRON HEM-907XL; Osaka, Japan). The study team will use the procedures adapted from previously validated methods and cardiovascular outcome studies, following recommendations for the American Heart Association and the European Society of Hypertension.
  • Change in fetal growth
    • Time Frame: Baseline, Gestation Week 24-28 and Gestation Week 32-36
    • Pregnant women will have ultrasounds at Baseline and during gestation weeks 24-28 and gestation weeks 32-36 to measure fetal growth. Abnormal fetal growth will be defined as an estimated fetal weight of less than the 10th percentile for gestational age based on the recently completed international standard for fetal growth (INTERGROWTH-21st) produced by the World Health Organization (WHO).
  • Preterm birth
    • Time Frame: Up to 5 months (within 24 hours of birth, 3-5 months post randomization)
    • Preterm birth is defined as delivery of a living infant prior to 37 completed weeks of gestation.
  • Change in child development
    • Time Frame: 3 months of age to 12 months of age
    • Child development will be assessed with the Caregiver Reported Early Childhood Development Instrument (CREDI). The CREDI is a population-level measure of early childhood development (ECD) for children from 0-3 years of age. The CREDI assesses 5 domains of child development: 1) motor development (fine and gross motor), 2) language development (expressive and receptive language), 3) cognitive development (executive function, problem solving and reasoning, and pre-academic knowledge), 4) socio-emotional development (emotional and behavioral self-regulation, emotional knowledge, and social competence), and 5) mental health (internalizing and externalizing behaviors). The CREDI long form has 117 items and the number of questions answered depends on the age of the child. Responses of “yes” are coded as 1 and “no” is coded as 0; certain items are reverse coded. Total raw scores increase by age (with developmental progression), and higher scores indicate increased development.
  • Brachial artery reactivity testing (BART)
    • Time Frame: 18 months
    • Brachial artery reactivity testing (BART) measures endothelial function via flow-mediated dilatation to reactive hyperemia following the release of arm blood-flow occlusion. In this test, baseline artery diameter is measured, then a blood pressure cuff is inflated to induce distal arm ischemia for 5 minutes and after releasing the pressure, the post-occlusion brachial artery diameter is measured. The ratio of post- to pre-occlusion artery diameter represents endothelial function where lower values indicate worse endothelial function. (Peru only)
  • Carotid intima-media thickness (CIMT)
    • Time Frame: 18 months
    • The carotid intima-media thickness test (CIMT) is used to determine the extent of carotid atherosclerotic vascular disease. The test measures the thickness of the inner two layers of the carotid artery and can detect plaque build up prior to physical symptoms being experienced. The carotid ultrasound will be performed with a portable ultrasound by trained sonographers.
  • Adult respiratory health and well-being
    • Time Frame: 18 months
    • Adult respiratory health and well-being will be assessed with the St. George Respiratory Questionnaire (SGRQ). The SGRQ measures impaired health and perceived well-being among individuals with chronic airway disease. The SGRQ has sections assessing symptoms, activities that cause breathlessness or are limited because of breathlessness, and the impacts of respiratory problems on employment, sense of control of health, panic, stigmatization, medication use, side effects of therapies, expectations for health and disturbances of daily life. The questionnaire includes multiple choice, true/false and open-ended questions.
  • Short Form 36 survey
    • Time Frame: 18 months
    • The Short Form 36 survey (SF-36) is a 36 item questionnaire evaluating quality of life. The survey has 8 sections (vitality, physical functioning, bodily pain, general health perceptions, physical role functioning, emotional role functioning, social role functioning, and mental health). Possible scores range from 0 (maximum disability) to 100 (no disability).
  • WHO severe pneumonia
    • Time Frame: Up to 12 months after birth
    • The number of times a child has WHO severe pneumonia (2014 definition) during the first year of life.

Participating in This Clinical Trial

Inclusion Criteria for Pregnant Women:

  • Confirmed pregnancy (hCG positive blood or urine test)
  • Aged 18 to <35 years (via self-report)
  • Uses biomass stove predominantly
  • Lives in study area
  • 9 – <20 weeks gestation confirmed by ultrasound
  • Singleton pregnancy (one fetus)
  • Viable fetus with normal fetal heart rate (120-180 beats per minute) at time of ultrasound
  • Continued pregnancy at the time of randomization confirmed by self-report
  • Agrees to participate with informed consent

Exclusion Criteria for Pregnant Women:

  • Currently smokes cigarettes or other tobacco products
  • Plans to move permanently outside study area in the next 12 months
  • Uses LPG stove predominantly, or is likely to use LPG predominantly in the near future

Inclusion Criteria for Older Adult Woman in the Same Household:

  • Aged 40 to <80 years (via self-report)

Exclusion Criteria for Older Adult Woman in the Same Household:

  • Currently smokes cigarettes or other tobacco products
  • Pregnant (by self-report)
  • Plans to move out of her current household in the next 12 months

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 79 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Emory University
  • Collaborator
    • National Institutes of Health (NIH)
  • Provider of Information About this Clinical Study
    • Principal Investigator: Thomas Clasen, Professor – Emory University
  • Overall Official(s)
    • Thomas Clasen, PhD, Principal Investigator, Emory University
    • Jennifer Peel, PhD, Principal Investigator, Colorado State University
    • William Checkley, MD PhD, Principal Investigator, Johns Hopkins School of Medicine

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