AsthmaNCT02763917
AIRWEIGHS: Investigating Obesity as a Susceptibility Factor for Air Pollution in Childhood Asthma
A study testing Active Air Purifier in people with Asthma, run by Johns Hopkins University at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 8 to 17 years
- Conditions the study is for
- Asthma
- What is being tested?
- Active Air Purifier
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 198 participants
- Where
- 1 siteUnited States
- Study dates
- Aug 2016to Sep 2027
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 8 to 17 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- 8-17 years of age
- Persistent asthma (NAEPP criteria)
- Exacerbation in previous 12 months
- Non-smoker
- Spends ≥4 nights/week at home
- No plans to move during the study
Who cannot join
- Significant pulmonary or cardiac disease
- Home not appropriate candidate due to disrepair
- Underweight, defined by BMI <5th percentile
- Pregnancy
Trial locations and contacts
1 site in 1 country.
About this study
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.
Read the 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
- Being tested
- Active Air Purifier, Placebo Air Purifier
- Medical subject headings
- Asthma
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Active Air PurifierDevice
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 PurifierDevice
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.
| Study group | Role | What they receive |
|---|---|---|
| Active Air Purifier | Active comparator | 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. Receives: Device: Active Air Purifier |
| Placebo Air Purifier | Placebo comparator | 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. Receives: Device: Placebo Air Purifier |
What is being measured
The primary outcome is the main question the study is designed to answer.
Maximum Symptom Days
We have chosen symptoms based on the strong relationship between symptoms and PM observed in previous studies. Symptoms during the previous two weeks will be captured with standardized questions used in many inner-city asthma studies, including our own that detected a strong association between indoor PM and asthma symptoms. A 'maximum symptom days' variable will constructed as the maximum of the variables: days of slowed activity, days of wheezing, coughing or chest tightness when running or going upstairs, and nights of waking with asthma symptoms in the past two weeks. We will administer questionnaires to the primary caregiver of children 8-11 years and to both participant and caregiver for adolescents age 12-17. Previous studies have indicated concordance between adolescent and the caregiver responses, and we will collect data to assess concordance within our study population. Individual symptom variables will serve as secondary outcomes.
Measured: Baseline and about 12 weeks after the intervention
Secondary outcomes (5)
Asthma Control
Asthma Control Questionnaire (ACT). This questionnaire assesses asthma control and a score of less than 19 has been linked to poor asthma control. The Asthma Therapy Assessment Questionnaire includes questions about asthma control and will also be used.
Measured: Baseline and about 12 weeks after the intervention
Asthma Symptoms
The Asthma Symptom Utility Index (ASUI) will be used to assess asthma symptoms.
Measured: Baseline and about 12 weeks after the intervention
Health Care Utilization
Child participants and caregivers will be asked about acute health care encounters during the study, including unscheduled doctor visits, Emergency Department visits, and hospitalizations. Acute visits occurred in approximately 30% of our previous study populations during a 3 month period.
Measured: Baseline and about 12 weeks after the intervention
Lung Function
Pre- and post-bronchodilator forced expiratory vital capacity in the first second/forced vital capacity (FEV1/FVC) and FEV1 will be measured and interpreted according to the American Thoracis Society (ATS) guidelines using NHANES predicted equations.
Measured: Baseline and about 12 weeks after the intervention.
FENO
Exhaled nitric oxide (FENO) will provide a non-invasive means of assessing pulmonary inflammation in a large cohort of children. Measurements will be obtained prior to lung function according to the American Thoracic Society Guidelines with handheld, FDA-approved analyzer (NIOX System, Aerocrine, Sweden)
Measured: Baseline and about 12 weeks after the intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 May 2016 (estimated)
- Study startAug 2016
- Primary completionSep 2026
- Study completionSep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for AsthmaStudies of the same condition, open and under way.
- More trials run by Johns Hopkins UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 198 participants (actual)
Sponsor and investigators
- Lead sponsor
- Johns Hopkins University
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute of Environmental Health Sciences (NIEHS)
- Responsible party
- Sponsor
- Investigators
- Meredith C. McCormack, MD, MHS, Principal investigator, Johns Hopkins University, Pulmonary and Critical Care Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02763917
- Sponsor's protocol ID
- IRB00074171
- Other IDs
- P50ES018176
- Status last verified
- Oct 2026
- First submitted
- 3 May 2016
- Last updated
- 22 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- Individual data sharing
- No
Publications
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.
PubMed 33625291