AIRWEIGHS: Investigating Obesity as a Susceptibility Factor for Air Pollution in Childhood Asthma
| Status: | Recruiting |
|---|---|
| Conditions: | Asthma |
| Therapuetic Areas: | Pulmonary / Respiratory Diseases |
| Healthy: | No |
| Age Range: | 8 - 17 |
| Updated: | 12/9/2018 |
| Start Date: | August 2016 |
| End Date: | August 2019 |
| Contact: | Meredith C. McCormack, MD, MHS |
| Email: | mmccor16@jhmi.edu |
| Phone: | 410-502-2806 |
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.
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.
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.
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.
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
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