Wood Stove Interventions and Child Respiratory Health

Rural and Native areas of the western United States (US) and Alaska experience substantial
exposure and health disparities compared to more populated urban centers. One such source of
disparity is the elevated inhalation exposures related to the use of wood stoves for home
heating. Within rural areas of Montana, Alaska, and the Navajo Nation, research has shown
that residential biomass combustion leads to indoor levels of fine particulate matter (PM2.5)
that often exceed current health-based air quality standards. Parallel findings have been
observed in several developing countries where biomass combustion is commonly used for
cooking and/or heating. This is concerning, as PM2.5 exposure is associated with many adverse
health outcomes, including a greater than three-fold increased risk of acute respiratory
tract infections. Throughout the world, lower respiratory tract infections (LRTIs) are the
most common cause of death in children under five years of age, and account for more than 27%
of all hospitalizations among US children under five years. Importantly, untoward effects of
recurrent LRTIs are cumulative in children and a recognized risk factor for asthma.

Currently, there is a global effort to reduce indoor biomass smoke exposures in developing
countries. A recent intervention trial found that exposure reductions following the
introduction of improved cookstoves was protective for severe infant pneumonia. Similar
evidence-based efforts are warranted in rural and Native American communities in the US that
suffer from elevated rates of childhood LRTI and commonly use wood for residential heating.
The investigators have previously demonstrated that a community-wide wood stove changeout
program (i.e., replacing old wood stoves with newer model wood stoves) resulted in reduced
wintertime ambient PM2.5 and corresponding reductions in occurrence of childhood wheeze and
respiratory infections. In this and other studies, however, inconsistent effects on indoor
air quality following the introduction of newer technology wood stoves have been observed.
The investigators have also shown that the introduction of air filtration units is a less
costly and more efficacious strategy for reducing indoor wood smoke exposures. Nevertheless,
the energy costs of operation and need for filter replacement (maintenance) remain barriers
to widespread dissemination and continued compliance in rural and economically disadvantaged
communities. Experience with these interventions and qualitative input from wood stove
experts suggest that educational interventions related to wood stove operation can translate
to low-cost and sustainable strategies that reduce indoor biomass combustion exposures and
improve respiratory health.

In this project, the investigators propose to test the efficacy of an education-based
intervention strategy for reducing indoor wood smoke exposures and children's risk of LRTI in
three unique and underserved settings. This study is a three-arm randomized trial in wood
stove homes with children less than five years old. Education on best-burn practices and
training on the use of simple instruments (i.e., stove thermometers and wood moisture meters)
will be introduced as one intervention arm (Tx1). This intervention will be evaluated against
an indoor air filtration unit arm (Tx2), as well as a placebo arm (Tx3, sham air filters).
The primary outcome will be LRTI incidence among children under five years of age. A sample
of 324 homes, or 108 within each study area equally assigned to each of the three
intervention arms, will allow for detection of exposure and outcome differences within each
of the three regions. Through three Aims, the overall hypothesis is that a low-cost,
educational intervention targeting indoor wood smoke (PM2.5) exposures will be an effective,
sustainable strategy for reducing children's risk of LRTI in underserved Native and rural
communities.

Aim 1: Compare LRTI incidence in each intervention arm (Tx1 and Tx2) to LRTI in the placebo
arm (Tx3). Investigators hypothesize that children less than five years old in intervention
homes will experience lower LRTI.

Aim 2: Compare indoor PM2.5 concentrations in each treatment arm relative to the placebo arm.
Investigators hypothesize that the intervention homes will have lower indoor PM2.5
concentrations.

Aim 3: Compare effectiveness and sustainability of treatment strategies relative to placebo,
both within and between regional sites. Investigators hypothesize that Tx1 will be more
effective and sustainable than Tx2.

Impact. LRTI is an important cause of morbidity among children, and exposure to biomass smoke
puts children at a greater risk of LRTI. By reducing in-home wood smoke exposures, this study
will evaluate sustainable evidence-based and culturally appropriate strategies for decreasing
occurrence of LRTI. In addition, comparing the effectiveness of these interventions across
three unique rural and Native regions will inform translation of study findings into diverse
settings that utilize biomass fuels for heating and cooking.

Inclusion Criteria:

- Eligible homes will be any home in the described communities that uses a wood stove as
a primary heating source, and has one or more children under the age of five years.
The home must include a parent who is capable and willing to record symptom data for
the enrolled children and wood stove usage data.

Exclusion Criteria: