AIRWEIGHS: Investigating Obesity as a Susceptibility Factor for Air Pollution in Childhood Asthma

NCT ID: NCT02763917

Last Updated: 2025-10-03

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 198 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2016-08-31
• Study Completion Date: 2027-09-30

Brief Summary

Background: Asthma and obesity are public health crises that have concurrently risen over the past decades, affecting millions of children in the United States and disproportionately affecting low-income minority children in urban areas. The same children at highest risk for asthma and obesity also have greater exposure to indoor and outdoor pollution. Emerging evidence suggests that obesity may confer increased susceptibility to health effects of air pollution.

Methods: Aiming to provide causal-level evidence of these observational findings, we propose a home intervention study to 1) test whether targeted reductions of indoor Particulate Matter (PM) concentrations improve the respiratory health of overweight inner-city children with asthma more than that of lean inner-city children with asthma and 2) investigate mediators of susceptibility to indoor PM among overweight versus lean children with asthma. We will accomplish these aims using a 1:1 randomized controlled trial of 200 children with persistent asthma (half normal weight, half overweight) living in Baltimore City. Participants will be randomized to receive either two active air purifiers containing high-efficiency particulate air (HEPA) filters or two sham air purifiers with their filters removed.

Implications: If the aforementioned observational findings are confirmed, implications will be directly relevant to the over 170 million children around the world now estimated to be overweight or obese.

Detailed Description

The primary object of this study is to determine the efficacy of a targeted environmental intervention among overweight inner city children as compared to normal weight inner city children with asthma.

Specific Aim #1: To determine if overweight inner-city children, compared to lean inner-city children, have greater improvement in asthma with an air purifier intervention aimed at reducing indoor PM.

Hypothesis 1: An intervention using HEPA filter air purifiers in the homes of inner-city children with asthma will be associated with greater respiratory improvement in overweight children than in normal weight children.

Specific Aim #2a: To investigate mediators of susceptibility among overweight versus normal weight children with asthma.

Hypothesis #2. Candidate mediators, including increases in a) tidal volume and thereby increases in doses of inhaled particles, b) inflammatory and oxidative stress responses, c) corticosteroid resistance, and d) sleep disordered breathing mediate increased susceptibility to indoor PM among overweight versus normal weight children with asthma.

Children with asthma will be enrolled in the study for about 16 weeks. They will have three clinic visits, an overnight sleep study, and two home environmental assessments for one week each. They will have a home and clinical assessment before randomization and another home and clinical assessment about 12 weeks after randomization. The primary outcome measure is maximum number of asthma symptom days.

Conditions

Asthma

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: OTHER
• Blinding Strategy: QUADRUPLE

Study Groups

Active Air Purifier

Two portable air purifiers containing HEPA filters will be placed in the bedroom and room where the participant reports spending the most time. We have chosen to deploy two air purifiers because we have observed a 50% reduction in indoor PM concentrations with two air purifiers. Participants will be instructed to run the air purifiers continually. Participants will receive educational materials about environmental factors that are important for asthma health and environmental modification strategies. Participants will also receive educational materials about health benefits of maintaining a normal weight.

Group Type: ACTIVE_COMPARATOR

Active Air Purifier

Intervention Type: DEVICE

Two portable air purifiers containing HEPA filters will be placed in the bedroom and room where the participant reports spending the most time. Participants will be instructed to run the air purifiers continually. Participants will receive educational materials about environmental factors that are important for asthma health and environmental modification strategies, and educational materials about health benefits of maintaining a normal weight.

Placebo Air Purifier

Homes in the control group will receive placebo air purifiers that have the internal air filters removed, but which will run normally. Participants will receive educational materials about environmental factors that are important for asthma health and environmental modification strategies, and educational materials about health benefits of maintaining a normal weight. At the end of the study, participants in the control group will receive active air purifiers. A control group is needed to ensure that reduced pollutant levels and health effects are not due to temporal trends and 'placebo effects' of being enrolled in an intervention trial. Participants will also be informed that being in the study does not prevent them from purchasing and using air cleaners during the study period.

Group Type: PLACEBO_COMPARATOR

Placebo Air Purifier

Intervention Type: DEVICE

Homes in the control group will receive placebo air purifiers that have the internal air filters removed, but which will run normally. Participants will receive educational materials about environmental factors that are important for asthma health and environmental modification strategies, and educational materials about health benefits of maintaining a normal weight. At the end of the study, participants in the control group will receive active air purifiers. A control group is needed to ensure that reduced pollutant levels and health effects are not due to temporal trends and 'placebo effects' of being enrolled in an intervention trial. Participants will be informed that being in the study does not prevent them from purchasing and using air cleaners during the study period.

Interventions

Active Air Purifier

Two portable air purifiers containing HEPA filters will be placed in the bedroom and room where the participant reports spending the most time. Participants will be instructed to run the air purifiers continually. Participants will receive educational materials about environmental factors that are important for asthma health and environmental modification strategies, and educational materials about health benefits of maintaining a normal weight.

Intervention Type: DEVICE

Placebo Air Purifier

Homes in the control group will receive placebo air purifiers that have the internal air filters removed, but which will run normally. Participants will receive educational materials about environmental factors that are important for asthma health and environmental modification strategies, and educational materials about health benefits of maintaining a normal weight. At the end of the study, participants in the control group will receive active air purifiers. A control group is needed to ensure that reduced pollutant levels and health effects are not due to temporal trends and 'placebo effects' of being enrolled in an intervention trial. Participants will be informed that being in the study does not prevent them from purchasing and using air cleaners during the study period.

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

1. 8-17 years of age

2. Persistent asthma (NAEPP criteria)

3. Exacerbation in previous 12 months

4. Non-smoker

5. Spends ≥4 nights/week at home

6. No plans to move during the study

Exclusion Criteria

1. Significant pulmonary or cardiac disease

2. Home not appropriate candidate due to disrepair

3. Underweight, defined by BMI <5th percentile

4. Pregnancy

• Minimum Eligible Age: 8 Years
• Maximum Eligible Age: 17 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

National Institute of Environmental Health Sciences (NIEHS)

NIH

Sponsor Role: collaborator

Johns Hopkins University

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Meredith C. McCormack, MD, MHS

Role: PRINCIPAL_INVESTIGATOR

Johns Hopkins University, Pulmonary and Critical Care Medicine

Locations

Meredith McCormack

Baltimore, Maryland, United States

Countries

United States

References

Kaviany P, Brigham EP, Collaco JM, Rice JL, Woo H, Wood M, Koehl R, Wu TD, Eakin MN, Koehler K, Hansel NN, McCormack MC. Patterns and predictors of air purifier adherence in children with asthma living in low-income, urban households. J Asthma. 2022 May;59(5):946-955. doi: 10.1080/02770903.2021.1893745. Epub 2021 Mar 10.

Reference Type: DERIVED

PMID: 33625291 (View on PubMed)

Other Identifiers

P50ES018176

Identifier Type: NIH

Identifier Source: secondary_id

View Link

IRB00074171

Identifier Type: -

Identifier Source: org_study_id