Indoor Air Pollution and Children With Asthma: An Intervention Trial

NCT ID: NCT02258893

Last Updated: 2020-11-23

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

116 participants

Study Classification

INTERVENTIONAL

Study Start Date

2016-01-01

Study Completion Date

2019-08-31

Brief Summary

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The purpose of this study is to determine whether reducing indoor exposure to NO2 and particles improves respiratory health in children with asthma.

Detailed Description

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We have designed a randomized, double-blind, triple cross-over intervention study to examine the efficacy of indoor NO2 reduction on reducing asthma severity. Since particles and NO2 are both byproducts of combustion and associated with gas stove use, the intervention protocol includes a condition using a filter designed to remove particles also implicated in asthma exacerbations (e.g., coarse, fine and ultrafine particles including airborne mold spores and allergens) while leaving NO2 virtually untouched. Primary and secondary aims of the trial include, respectively, determining whether reducing exposure to NO2 and particles compared to a "control" (non-filtered) condition results in a clinically significant reduction in asthma severity measured by a difference in days of symptoms between intervention arms.

Families with asthmatic children age 5-11 will be recruited from selected communities using a: (1) flyers distributed in elementary schools, (2) postcards send to families from purchased mailing lists, (3) posters placed in community buildings (libraries, clinics, etc.), (4) online (Facebook, Craigslist), and (5) letter mailed to families targeted through Yale Joint Data Analytics Team (JDAT). Volunteers will be screened for preliminary eligibility based on household characteristics and active asthmatic status. Potentially eligible families will have homes with a gas cooking stove and seven rooms or fewer. Potentially eligible children will be aged 5-11; have asthma symptoms and/or medication use consistent with severity score categories 2 (mild persistent), 3 (moderate), or 4 (severe) during the previous 12 months; and reside at least 5 days and nights every week in the eligible home.

Households meeting these preliminary criteria will be asked to participate in passive NO2 sampling. A single Palmes tube will be sent to the home for placement in the main living space for one week. Families will be called after one week and instructed to cap and return the NO2 monitor in a pre-paid mailer. Families of children living in homes where the one-week integrated average NO2 concentration is ≥ 15 ppb will be invited to participate. We will permit enrollment of more than one eligible child per family. Participating families will be randomized into one of 6 treatment sequences each requiring 3 periods of 4-weeks preceded by a 1-week washout period. Randomization will be blocked so that for every 18 subjects randomized there will be 3 in each sequence. Randomization will be conducted blindly by the data management department such that each scheduled initial interview/air cleaner installation is assigned a treatment sequence (referring to machines and filters already on site). Minimization techniques will be used to balance the randomized allocation as necessary. Total subject participation time up to 18 weeks.

Conditions

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Asthma

Keywords

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Nitrogen Dioxide Parts per billion

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Primary Study Purpose

TREATMENT

Blinding Strategy

DOUBLE

Participants Investigators

Study Groups

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NO2 Scrubber, then HEPA filter, then Control

Participants will have 3 periods of 4 weeks with each filter with a 1 week washout between phases in the order of NO2 Scrubber, then HEPA filter, then Control.

Group Type EXPERIMENTAL

NO2 Scrubber

Intervention Type OTHER

an NO2 scrubber that removes NO2 and particles

HEPA filter

Intervention Type OTHER

a HEPA filter that removes 95% of suspended particles ≥ 0.003 μm in size (but does not remove NO2)

Control

Intervention Type OTHER

a "control" filter designed to be the same size and weight as the other two filters, but filters neither NO2 nor particles

NO2 Scrubber, then Control, then HEPA filter

Participants will have 3 periods of 4 weeks with each filter with a 1 week washout between phases in the order of NO2 Scrubber, then Control, then HEPA filter

Group Type EXPERIMENTAL

NO2 Scrubber

Intervention Type OTHER

an NO2 scrubber that removes NO2 and particles

HEPA filter

Intervention Type OTHER

a HEPA filter that removes 95% of suspended particles ≥ 0.003 μm in size (but does not remove NO2)

Control

Intervention Type OTHER

a "control" filter designed to be the same size and weight as the other two filters, but filters neither NO2 nor particles

HEPA filter, then NO2 scrubber, then Control

Participants will have 3 periods of 4 weeks with each filter with a 1 week washout between phases in the order of HEPA filter, then NO2 scrubber, then Control

Group Type EXPERIMENTAL

NO2 Scrubber

Intervention Type OTHER

an NO2 scrubber that removes NO2 and particles

HEPA filter

Intervention Type OTHER

a HEPA filter that removes 95% of suspended particles ≥ 0.003 μm in size (but does not remove NO2)

Control

Intervention Type OTHER

a "control" filter designed to be the same size and weight as the other two filters, but filters neither NO2 nor particles

HEPA filter, then Control, then NO2 scrubber

Participants will have 3 periods of 4 weeks with each filter with a 1 week washout between phases in the order of HEPA filter, then Control, then NO2 scrubber

Group Type EXPERIMENTAL

NO2 Scrubber

Intervention Type OTHER

an NO2 scrubber that removes NO2 and particles

HEPA filter

Intervention Type OTHER

a HEPA filter that removes 95% of suspended particles ≥ 0.003 μm in size (but does not remove NO2)

Control

Intervention Type OTHER

a "control" filter designed to be the same size and weight as the other two filters, but filters neither NO2 nor particles

Control, then HEPA filter, then NO2 scrubber

Participants will have 3 periods of 4 weeks with each filter with a 1 week washout between phases in the order of Control, then HEPA filter, then NO2 scrubber

Group Type EXPERIMENTAL

NO2 Scrubber

Intervention Type OTHER

an NO2 scrubber that removes NO2 and particles

HEPA filter

Intervention Type OTHER

a HEPA filter that removes 95% of suspended particles ≥ 0.003 μm in size (but does not remove NO2)

Control

Intervention Type OTHER

a "control" filter designed to be the same size and weight as the other two filters, but filters neither NO2 nor particles

Control, then NO2 scrubber, then HEPA filter

Participants will have 3 periods of 4 weeks with each filter with a 1 week washout between phases in the order of Control, then NO2 scrubber, then HEPA filter

Group Type EXPERIMENTAL

NO2 Scrubber

Intervention Type OTHER

an NO2 scrubber that removes NO2 and particles

HEPA filter

Intervention Type OTHER

a HEPA filter that removes 95% of suspended particles ≥ 0.003 μm in size (but does not remove NO2)

Control

Intervention Type OTHER

a "control" filter designed to be the same size and weight as the other two filters, but filters neither NO2 nor particles

Interventions

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NO2 Scrubber

an NO2 scrubber that removes NO2 and particles

Intervention Type OTHER

HEPA filter

a HEPA filter that removes 95% of suspended particles ≥ 0.003 μm in size (but does not remove NO2)

Intervention Type OTHER

Control

a "control" filter designed to be the same size and weight as the other two filters, but filters neither NO2 nor particles

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

* 5-11 years of age, enrolled in grades K-5 and living in the recruitment area (CT, MA)
* \[The screening questionnaire will determine asthma symptoms in the past 12 months (wheeze, persistent cough, shortness of breath, chest tightness); and asthma medication use in the past 12 months (short-acting β2-agonists, long-acting β2-agonists, inhaled steroids, oral steroids, theophylline, cromones, and/or leukotriene inhibitors). Based on symptoms and medication, asthma severity will be categorized with a score adapted from the Global Initiative for Asthma guidelines (1=mild transient, 2=mild persistent, 3=moderate, 4=severe). Only children in categories 2 (mild persistent, 3 (moderate) or 4 (severe) will be eligible.\]

Exclusion Criteria

* Using steroid medication for a condition other than asthma
* Chronic respiratory condition other than asthma
* Intention to move or relocate within 6 months
Minimum Eligible Age

5 Years

Maximum Eligible Age

11 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Harvard University

OTHER

Sponsor Role collaborator

National Institute of Environmental Health Sciences (NIEHS)

NIH

Sponsor Role collaborator

Yale University

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Brian Leaderer, PhD, MPH

Role: PRINCIPAL_INVESTIGATOR

Yale University

Michael Bracken, PhD MPH FACE

Role: PRINCIPAL_INVESTIGATOR

Yale University

Theodore Holford, PhD

Role: PRINCIPAL_INVESTIGATOR

Yale University

Janneane Gent, PhD

Role: PRINCIPAL_INVESTIGATOR

Yale University

Locations

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Yale University

New Haven, Connecticut, United States

Site Status

Countries

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United States

References

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Gent JF, Holford TR, Bracken MB, Plano JM, McKay LA, Sorrentino KM, Koutrakis P, Leaderer BP. Childhood asthma and household exposures to nitrogen dioxide and fine particles: a triple-crossover randomized intervention trial. J Asthma. 2023 Apr;60(4):744-753. doi: 10.1080/02770903.2022.2093219. Epub 2022 Jul 7.

Reference Type DERIVED
PMID: 35796019 (View on PubMed)

Other Identifiers

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5R01ES023505-05

Identifier Type: NIH

Identifier Source: secondary_id

View Link

1308012531

Identifier Type: -

Identifier Source: org_study_id