Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04729530 |
| Other study ID # |
DYSON-ASTHMA01 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
September 3, 2019 |
| Est. completion date |
July 21, 2021 |
Study information
| Verified date |
August 2022 |
| Source |
The David Hide Asthma & Allergy Research Centre |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
To investigate the effect of reducing the level of allergens and pollutants in the bedroom
and living room by placing a "Dyson air purifier", on poorly controlled asthmatic subjects.
Description:
Asthma is one of the most common chronic diseases. Little change in morbidity and mortality
has occurred despite improvements in pharmacotherapy. In the last few decades, there has been
an increase in the prevalence of asthma and other allergic diseases. The precise cause for
this increase in disease prevalence is not known but it has coincided with changes to the
quality of indoor air with increases in the levels of allergens and pollutants. Bedroom
exposure to dust-mite allergens has been linked to worsening asthma symptoms and increase in
bronchial responsiveness. In places where dust mites cannot thrive, allergens from cat,
cockroach and Alternaria assume importance. High indoor temperatures and humidity may, by a
number of mechanisms, increase the allergenic burden, particularly the proliferation of
house-dust mites and moulds. Therefore, modern living conditions are associated with a higher
risk of allergen exposure causing increase in sensitisation and symptoms of asthma. In
addition to allergens, the indoor environment contains other biological materials (such as
microbiome and endotoxin), and pollutants (gases and particulate matter) which can adversely
affect asthma development and morbidity. Indoor pollutants include smoke from cigarettes and
wood, coal or gas fires, particulate materials associated with bio-fuel combustion, chemical
vapours and gases including nitrogen dioxide (NO2), formaldehyde and volatile organic
compounds (VOCs). The latter may come from sources including building products, cleaning
agents, and paints. One such VOC is formaldehyde, which can be irritant to both upper and
lower respiratory tract. Small particulate matter (PM2.5) is particularly damaging as it gets
to the small airways of the lung. Major indoor sources of NO2 and particulate matter include
gas stoves and cigarette smoke but outdoor sources such as traffic and industrial pollution
can also contaminate indoor environment.
It has also been suggested that exposure to pollutants can potentiate the effects of
allergen. Indeed, a combination of high levels of indoor pollution and allergens is causally
related to the development and severity of asthma. Allergens, microbiome and pollutants can
interact with each other to augment the immune response leading to harmful effects on the
airways.
Thus, indoor air pollution is a significant environmental trigger for acute exacerbation of
asthma (and other respiratory conditions such as COPD), leading to increasing symptoms,
emergency department visits, hospital admissions and even mortality. An estimated 75% of
hospital admissions for asthma are avoidable. Maintaining high air quality with lower levels
of allergens and pollutants is therefore important in improving the health of individuals
with asthma and other respiratory diseases. Therefore, a feasible and practical intervention
that can reduce allergen and pollutant levels in the indoor air should reduce morbidity and
improve asthma control.
