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Wood Smoke Interventions in Native American Populations

Residential Wood Smoke Interventions Improving Health in Native American Populations

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT02240069
Acronym
EldersAIR
Enrollment
149
Registered
2014-09-15
Start date
2015-11-30
Completion date
2021-02-28
Last updated
2022-12-01

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Respiratory; Disorder, Functional, Impaired, Respiratory Infection Other

Brief summary

A critical need exists for efficient community-based interventions aimed at reduction of environmental exposures relevant to health. Biomass smoke exposures due to residential wood heating are common among rural Native American communities, and such exposures have been associated with respiratory disease in susceptible populations. In many of these communities wood stoves are the most economic and traditionally preferred method of residential heating, but resource scarcity can result in burning of improper wood fuels and corresponding high levels of indoor particulate matter. Community-based participatory research techniques will be used to adapt intervention approaches to meet the cultural context of each participating community. At the community level, investigators will facilitate local development of a tribal agency-led wood bank program ensuring that elderly and/or persons with need have access to dry wood for heating. At the household level, investigators will use a three arm randomized placebo-controlled intervention trial to implement and assess education/outreach on best burn practices (Tx1). The content and delivery strategies of the education intervention will be adapted to each community according to stakeholder input. This educational intervention will be evaluated against an indoor air filtration unit arm (Tx2), as well as a placebo arm (Tx3, sham air filters). Tx3 will be used in comparison with the other two treatment arms to evaluate the penetration and efficacy of the community-level wood bank program. Outcomes will be evaluated with respect to changes in pulmonary function measures and respiratory symptoms and conditions among household elders. The investigators hypothesize that locally-designed education-based interventions at the community and household levels will result in efficacious and sustainable strategies for reducing personal exposures to indoor particulate matter, and lead to respiratory health improvements in elderly Native populations. This study will advance knowledge of cost-effective environmental interventions within two unique Native American communities, and inform sustainable multi-level strategies in similar communities throughout the US to improve respiratory health among at-risk populations.

Detailed description

Rural Native American (NA) communities experience disproportionate disease burden compared to other US populations, with poor indoor air quality resulting from in-home biomass smoke exposures (residential wood stoves) a likely contributor to these health burden discrepancies. Epidemiological studies support the etiological association between indoor biomass smoke exposure and several domains of global disease burden, particularly with respect to pediatric respiratory tract infections and adult chronic obstructive pulmonary disease (COPD) and chronic bronchitis. Elderly populations are particularly susceptible to chronic respiratory conditions, and declining pulmonary function is associated with increased morbidity and mortality. Randomized trials in developing countries have demonstrated the impact that improved cookstove technologies have in reducing biomass smoke exposures and children's risk of acute respiratory infection. However limited knowledge is available regarding the potential improvements in NA elderly populations following wood stove interventions. Today, a critical need exists for efficient community-based interventions aimed at promoting healthy indoor environments in at-risk communities. Financial and logistical barriers that currently exist in rural and economically disadvantaged NA communities prohibit the implementation and sustainability of many environmental health interventions. Regarding wood stoves, qualitative input from experts and Native communities underscores the need for innovative low-cost, sustainable interventions targeting the reduction of in-home biomass smoke exposures. In this proposal, investigators will test community-level and education-based household-level strategies aimed at promoting and implementing best-burn practices to improve air quality and respiratory health in at-risk elderly populations. This proposal represents a multidisciplinary collaboration between university and tribal stakeholders from two Native American Reservations to develop, adapt, implement, and evaluate a two-level intervention to reduce exposure to indoor biomass smoke and improve respiratory health among elderly tribal members. Community-based participatory research techniques will be used to adapt intervention approaches to meet the cultural context of each participating community. At the community level, investigators will facilitate local development of tribal agency-led wood yard and distribution programs ensuring that elderly and/or persons with need have access to dry wood for heating. With community advisory guidance, investigators will use a three arm randomized placebo-controlled intervention trial to implement and assess education on best burn practices (Tx1) at the household level. This educational intervention will be evaluated against an indoor air filtration unit arm (Tx2), as well as a placebo arm (Tx3, sham air filters). Tx3 will be used in comparison with the other two treatment arms to evaluate the penetration and efficacy of the community-level fuel program. Outcomes will be evaluated with respect to changes in markers of respiratory health among elders and changes in indoor air quality (PM2.5). The investigators hypothesize that locally-designed education-based interventions, in the context of a community-based strategy focused on wood fuels, will result in efficacious and sustainable strategies for reducing personal exposures to indoor biomass smoke PM2.5 and lead to respiratory health improvements in elderly NA populations. Specific Aims are as follows: Aim 1. Facilitate the tribally-centered development, adaption, implementation, and evaluation of community-level wood yard and distribution programs for participating tribal households. Aim 2. Facilitate the development, adaptation, implementation, and evaluation of household-level education strategies targeting best-burn practices (Tx1) for each participating tribal community. Aim 3. Compare effectiveness, both within and between communities, of household-level interventions among elderly adults participating in a three-arm randomized placebo-controlled trial. Aim 3a. Compare group changes in pulmonary function and respiratory symptoms and infections. Aim 3b. Compare group changes in indoor and personal PM2.5 exposures. Aim 4. Evaluate penetration, acceptance, and sustainability of community- and household-level strategies using both qualitative and quantitative data generated in collaboration with tribal community advisory boards and research participants. Impact. The long-term goal of this project will be to reduce mortality and morbidity in NA communities from exposures related to residential home heating. This study will advance knowledge of effective interventions within two unique NA Reservations and describe improvements in sub-clinical indicators of pulmonary health in susceptible elderly populations. Reducing in-home wood smoke exposures through community level facilitation of access to proper fuels and introduction of sustainable, culturally appropriate best-burn practices will inform strategies for translation to other NA communities or similar rural and underserved populations.

Interventions

BEHAVIORALEducation (Tx1)

Education on best burn practices

A 20 x 18 Filtrete air filtration unit (3M, St. Paul, MN) will be placed in the same room as the wood stove

A 20 x 18 Filtrete air filtration unit will be installed within the wood stove home. Instead of a high efficiency filter, the units will utilize a placebo filter.

Sponsors

National Institute of Environmental Health Sciences (NIEHS)
CollaboratorNIH
University of Montana
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
SINGLE (Subject)

Eligibility

Sex/Gender
ALL
Age
55 Years to No maximum
Healthy volunteers
Yes

Inclusion criteria

* Tribal member from one of the two study regions * Age 55 years or older. * Utilize a wood stove as the primary heating source. * Capable and willing to record symptom data and wood stove usage data, as well as complete pulmonary function testing (i.e., spirometry).

Design outcomes

Primary

MeasureTime frameDescription
Post-intervention FEV1Each participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Health measures were collected at two visits during both winter periods with each visit separated by at least three weeks.Mean of up to two post-intervention measures of forced expiratory volume at one second (FEV1), liters
Post-intervention FVCEach participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Health measures were collected at two visits during both winter periods with each visit separated by at least three weeks.Mean of up to two post-intervention measures of forced vital capacity (FVC), liters
Post-intervention FEV1/FVC RatioEach participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Health measures were collected at two visits during both winter periods with each visit separated by at least three weeks.Mean of up to two post-intervention measures of forced expiratory volume at one second (FEV1) / forced vital capacity (FVC)
Post-intervention Systolic Blood PressureEach participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Health measures were collected at two visits during both winter periods with each visit separated by at least three weeks.Mean of up to two post-intervention measures of systolic blood pressure, millimeters of mercury (mmHg)
Post-intervention Diastolic Blood PressureEach participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Health measures were collected at two visits during both winter periods with each visit separated by at least three weeks.Mean of up to two post-intervention measures of diastolic blood pressure, millimeters of mercury (mmHg)

Secondary

MeasureTime frameDescription
Post-intervention Indoor Fine Particulate Matter (PM2.5)Each participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Indoor 48-hour PM2.5 average concentration was measured at two post-intervention visits separated by at least three weeks.Post-intervention average Indoor fine particulate matter (PM2.5) concentration

Countries

United States

Participant flow

Pre-assignment details

For this pre/post study recruited and consented participants completed baseline measures during a pre-intervention period (n=149). Randomization to arms occurred after the first (baseline) period and before the second (post-intervention) period. Six participants dropped out of the study before the randomization process. Thus, only 143 participants were randomized to a treatment arm.

Participants by arm

ArmCount
Education (Tx1)
Education on best burn practices Education (Tx1): Education on best burn practices
49
Air Filtration Unit Treatment (Tx2)
A 20 x 18 Filtrete air filtration unit (3M, St. Paul, MN) will be placed in the same room as the wood stove. Air Filtration Unit Treatment (Tx2): A 20 x 18 Filtrete air filtration unit (3M, St. Paul, MN) will be placed in the same room as the wood stove
47
Placebo Intervention (Tx3)
A 20 x 18 Filtrete air filtration unit will be installed within the wood stove home. Instead of a high efficiency filter, the units will utilize a placebo filter. Placebo Intervention (Tx3): A 20 x 18 Filtrete air filtration unit will be installed within the wood stove home. Instead of a high efficiency filter, the units will utilize a placebo filter.
47
Total143

Withdrawals & dropouts

PeriodReasonFG000FG001FG002
Overall StudyWithdrawal by Subject552

Baseline characteristics

CharacteristicPlacebo Intervention (Tx3)Education (Tx1)TotalAir Filtration Unit Treatment (Tx2)
Age, Continuous68.9 years
STANDARD_DEVIATION 8.7
69.8 years
STANDARD_DEVIATION 9.3
69.6 years
STANDARD_DEVIATION 9.2
69.8 years
STANDARD_DEVIATION 9.5
Diastolic blood pressure77 mmHg
STANDARD_DEVIATION 14
74 mmHg
STANDARD_DEVIATION 11
77 mmHg
STANDARD_DEVIATION 12
79 mmHg
STANDARD_DEVIATION 10
Ethnicity (NIH/OMB)
Hispanic or Latino
1 Participants3 Participants5 Participants1 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
46 Participants46 Participants138 Participants46 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants0 Participants
FEV1/FVC0.79 ratio
STANDARD_DEVIATION 0.08
0.79 ratio
STANDARD_DEVIATION 0.08
0.79 ratio
STANDARD_DEVIATION 0.08
0.80 ratio
STANDARD_DEVIATION 0.07
Forced expiratory volume in 1 second (FEV1)2.0 liters
STANDARD_DEVIATION 0.8
2.1 liters
STANDARD_DEVIATION 0.7
2.0 liters
STANDARD_DEVIATION 0.7
2.1 liters
STANDARD_DEVIATION 0.6
Forced vital capacity (FVC)2.5 liters
STANDARD_DEVIATION 0.9
2.6 liters
STANDARD_DEVIATION 0.8
2.6 liters
STANDARD_DEVIATION 0.8
2.6 liters
STANDARD_DEVIATION 0.7
Race (NIH/OMB)
American Indian or Alaska Native
47 Participants48 Participants138 Participants43 Participants
Race (NIH/OMB)
Asian
0 Participants0 Participants1 Participants1 Participants
Race (NIH/OMB)
Black or African American
0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
More than one race
0 Participants1 Participants4 Participants3 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants0 Participants
Race (NIH/OMB)
White
0 Participants0 Participants0 Participants0 Participants
Sex: Female, Male
Female
31 Participants36 Participants100 Participants33 Participants
Sex: Female, Male
Male
16 Participants13 Participants43 Participants14 Participants
Systolic blood pressure137 mmHg
STANDARD_DEVIATION 20
132 mmHg
STANDARD_DEVIATION 18
137 mmHg
STANDARD_DEVIATION 19
143 mmHg
STANDARD_DEVIATION 19

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
deaths
Total, all-cause mortality
0 / 490 / 470 / 47
other
Total, other adverse events
0 / 490 / 470 / 47
serious
Total, serious adverse events
0 / 490 / 470 / 47

Outcome results

Primary

Post-intervention Diastolic Blood Pressure

Mean of up to two post-intervention measures of diastolic blood pressure, millimeters of mercury (mmHg)

Time frame: Each participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Health measures were collected at two visits during both winter periods with each visit separated by at least three weeks.

Population: Valid post-intervention blood pressure measures captured for 128 of 143 participants

ArmMeasureValue (MEAN)Dispersion
Education (Tx1)Post-intervention Diastolic Blood Pressure75 millimeters of mercury (mmHg)Standard Deviation 11
Air Filtration Unit Treatment (Tx2)Post-intervention Diastolic Blood Pressure78 millimeters of mercury (mmHg)Standard Deviation 11
Placebo Intervention (Tx3)Post-intervention Diastolic Blood Pressure76 millimeters of mercury (mmHg)Standard Deviation 13
Comparison: Pre- to post-intervention change in diastolic blood pressure for Education group relative to Placebo groupp-value: 0.6595% CI: [-5.42, 3.42]Mixed Models Analysis
Comparison: Pre- to post-intervention change in diastolic blood pressure for Filter group relative to Placebo groupp-value: 0.7995% CI: [-4.97, 3.81]Mixed Models Analysis
Primary

Post-intervention FEV1

Mean of up to two post-intervention measures of forced expiratory volume at one second (FEV1), liters

Time frame: Each participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Health measures were collected at two visits during both winter periods with each visit separated by at least three weeks.

Population: Valid post-intervention spirometry measures captured for 127 of 143 participants

ArmMeasureValue (MEAN)Dispersion
Education (Tx1)Post-intervention FEV11.9 litersStandard Deviation 0.7
Air Filtration Unit Treatment (Tx2)Post-intervention FEV12.1 litersStandard Deviation 0.6
Placebo Intervention (Tx3)Post-intervention FEV12.0 litersStandard Deviation 0.6
Comparison: Pre- to post-intervention change in FEV1 for Education group relative to Placebo groupp-value: 0.195% CI: [-0.24, 0.02]Mixed Models Analysis
Comparison: Pre- to post-intervention change in FEV1 for Filtration group relative to Placebo groupp-value: 0.995% CI: [-0.11, 0.13]Mixed Models Analysis
Primary

Post-intervention FEV1/FVC Ratio

Mean of up to two post-intervention measures of forced expiratory volume at one second (FEV1) / forced vital capacity (FVC)

Time frame: Each participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Health measures were collected at two visits during both winter periods with each visit separated by at least three weeks.

Population: Valid post-intervention spirometry measures captured for 127 of 143 participants

ArmMeasureValue (MEAN)Dispersion
Education (Tx1)Post-intervention FEV1/FVC Ratio0.78 ratioStandard Deviation 0.08
Air Filtration Unit Treatment (Tx2)Post-intervention FEV1/FVC Ratio0.79 ratioStandard Deviation 0.08
Placebo Intervention (Tx3)Post-intervention FEV1/FVC Ratio0.80 ratioStandard Deviation 0.08
Comparison: Pre- to post-intervention change in FEV1/FVC for Education group relative to Placebo groupp-value: 0.0695% CI: [-0.05, 0]Mixed Models Analysis
Comparison: Pre- to post-intervention change in FEV1/FVC for Filter group relative to Placebo groupp-value: 0.7195% CI: [-0.03, 0.02]Mixed Models Analysis
Primary

Post-intervention FVC

Mean of up to two post-intervention measures of forced vital capacity (FVC), liters

Time frame: Each participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Health measures were collected at two visits during both winter periods with each visit separated by at least three weeks.

Population: Valid post-intervention spirometry measures captured for 127 of 143 participants

ArmMeasureValue (MEAN)Dispersion
Education (Tx1)Post-intervention FVC2.4 litersStandard Deviation 0.7
Air Filtration Unit Treatment (Tx2)Post-intervention FVC2.7 litersStandard Deviation 0.7
Placebo Intervention (Tx3)Post-intervention FVC2.5 litersStandard Deviation 0.7
Comparison: Pre- to post-intervention change in FVC for Education group relative to Placebo groupp-value: 0.2895% CI: [-0.24, 0.07]Mixed Models Analysis
Comparison: Pre- to post-intervention change in FVC for Filter group relative to Placebo groupp-value: 0.8995% CI: [-0.14, 0.16]Mixed Models Analysis
Primary

Post-intervention Systolic Blood Pressure

Mean of up to two post-intervention measures of systolic blood pressure, millimeters of mercury (mmHg)

Time frame: Each participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Health measures were collected at two visits during both winter periods with each visit separated by at least three weeks.

Population: Valid post-intervention blood pressure measures captured for 128 of 143 participants

ArmMeasureValue (MEAN)Dispersion
Education (Tx1)Post-intervention Systolic Blood Pressure132 millimeters of mercury (mmHg)Standard Deviation 16
Air Filtration Unit Treatment (Tx2)Post-intervention Systolic Blood Pressure139 millimeters of mercury (mmHg)Standard Deviation 17
Placebo Intervention (Tx3)Post-intervention Systolic Blood Pressure136 millimeters of mercury (mmHg)Standard Deviation 22
Comparison: Pre- to post-intervention change in systolic blood pressure for Education group relative to Placebo groupp-value: 0.3995% CI: [-11.45, 4.54]Mixed Models Analysis
Comparison: Pre- to post-intervention change in systolic blood pressure for Filter group relative to Placebo groupp-value: 0.9595% CI: [-7.73, 8.24]Mixed Models Analysis
Secondary

Post-intervention Indoor Fine Particulate Matter (PM2.5)

Post-intervention average Indoor fine particulate matter (PM2.5) concentration

Time frame: Each participant was followed during a pre-intervention baseline (Winter 1) and a post-intervention follow-up period (Winter 2). Indoor 48-hour PM2.5 average concentration was measured at two post-intervention visits separated by at least three weeks.

Population: Valid post-intervention PM2.5 measures captured for 123 of 143 households

ArmMeasureValue (MEAN)Dispersion
Education (Tx1)Post-intervention Indoor Fine Particulate Matter (PM2.5)38.8 microgram/cubic meterStandard Deviation 33.9
Air Filtration Unit Treatment (Tx2)Post-intervention Indoor Fine Particulate Matter (PM2.5)30.5 microgram/cubic meterStandard Deviation 51.5
Placebo Intervention (Tx3)Post-intervention Indoor Fine Particulate Matter (PM2.5)41.6 microgram/cubic meterStandard Deviation 39.2
Comparison: Pre- to post-intervention change in indoor PM2.5 concentration for Education group relative to Placebo groupp-value: 0.8895% CI: [-33.6, 42]Mixed Models Analysis
Comparison: Pre- to post-intervention change in indoor PM2.5 concentration for Filter group relative to Placebo groupp-value: <0.00195% CI: [-66.1, -27.8]Mixed Models Analysis

Source: ClinicalTrials.gov · Data processed: Feb 8, 2026