AsthmaVent - Effect of Mechanical Ventilation on Asthma Control in Children
Condition: Childhood Asthma; Allergy
MeSH terms: Asthma
Study type: Interventional

Summary: 
      AsthmaVent is a multi-center study, investigating the association between indoor air quality
      and childhood asthma.

      In Denmark, we spend more and more time indoors. Our houses are built airtight to save energy
      and are difficult to ventilate. We are thus more exposed to our indoor air than ever before.
      We know that indoor air contains many different components that can affect our airways
      inappropriately and particularly children with asthma, who have sensitive airways are
      sensitive to these components. The AsthmaVent project examines whether increased ventilation
      is able to improve the indoor environment to such an extent that the asthma disease control,
      for children with asthma and house dust mite allergy improves, resulting in need for less
      medication.

      Previous studies have pointed towards a beneficial effect of mechanical ventilation, on both
      the indoor air quality and on children's health and quality of life. There is not currently a
      consensus in this area, as studies so far have not been large or good enough to confidently
      determine the effect.

      This project is big and is designed so that it takes into account the sources of error seen
      in previous studies on the topic.

      We include, over a 3-year period (2012-2014), a total of 80 children with asthma and house
      dust mite allergy aged 6-18 years, from pediatric departments in Aarhus, Odense, Kolding,
      Randers and Herning. They are divided into two groups, receiving either active ventilation or
      placebo ventilation, meaning a non-functioning ventilation system that just recirculates the
      air in the room. Ventilation systems are installed in the fall and winter and ventilate the
      child's bedroom during 9 months. Indoor air quality and asthma control are assessed every 3
      months, both at home visits were air quality and allergen levels of house dust mites are
      studies and at visits to the outpatient clinics with control of asthma parameters and quality
      of life.

      The project involves collaboration between several institutions with an interest in indoor
      air quality in relation to allergies and asthma and with great expertise in the field.The
      project was initiated by CISBO (Centre for Indoor Environment and Health in Dwellings), a
      center consisting of several institutions in Denmark dealing with indoor environment:
      Department of Public Health at Aarhus University and University of Copenhagen, Danish
      Building Research Institute and the Technical University of Denmark.

      Since asthma is the most common chronic childhood disease in Denmark and since the
      development of allergies and asthma has high social and personal costs, it is important for
      both society and the individual family, to find out whether simply improving the indoor air
      quality by increased ventilation can lead to an improvement in asthma disease control.
    

Detailed description: 
      The aim of the project is to investigate whether increased ventilation is able to improve the
      indoor air quality and thereby asthma disease control for children with asthma and house dust
      mite allergy.

      Hypotheses:

        1. An increased ventilation in the home will reduce the need for inhaled steroids in
           children with house dust mite allergy and asthma.

        2. An increased ventilation in the home will improve the quality of life in children with
           house dust mite allergy and asthma.

        3. An increased ventilation in the home will improve the indoor environment and thus
           improve asthma disease control in children with house dust mite allergy and asthma.

      Materials and methods: The study is a randomized double-blind placebo-controlled intervention
      study. The intervention is balanced mechanical ventilation in the bedroom of children with
      asthma and house dust mite allergy during 9-months.

      Population: Over 3 year period (2012-2014) 80 families with asthmatic children aged 6-18
      years will be included from out-patient clinics at the children's department of the
      University Hospitals of Aarhus and Odense and regional hospitals in Kolding, Randers and
      Herning. Families will also be included from private pediatric clinics in Aarhus.

      Randomization: After inclusion children are randomized to either active ventilation or
      placebo ventilation. Randomization is done in blocks of 4 by center.

      Intervention: The ventilation units Type DUPLEX 370 EC4.D and DUPLEX 370 are installed during
      the fall and run continuously for 9 months. The ventilation system is placed outside the
      house and provides filtered conditioned air to the child's bedroom, through insulated pipes
      mounted in a window opening. The window opening was built specifically for this purpose in
      form of a thermo plate replacing the window glass. The unit provides the bedroom with at
      least 2-3 air changes per hour. The placebo unit (DUPLEX 370) is a completely similar
      installation which only recirculates the air in the room instead of replacing it. We
      recommend all parents to wash the duvet and pillow every 3 months.

      Data collection:

      Data on the children's health is collected every 3 months when the families visit the
      outpatient clinics. The children are seen by specialist doctors.

      At home visits, also every 3 months, data concerning the indoor air quality is collected.
    

Intervention name(s): Ventilation; Placebo Ventilation
Intervention type(s): Device; Device
Intervention description(s): The ventilation system is placed outside the house and provides filtered conditioned air to the child's bedroom, through insulated pipes mounted in a window opening. The window opening was built specifically for this purpose in form of a thermo plate replacing the window glass. The unit provides the bedroom with at least 2-3 air changes per hour; The placebo unit (DUPLEX 370) is a completely similar installation to the active ventilation unit, but it only recirculates the air in the room instead of replacing it with fresh conditioned air.
Other intervention name(s): Ventilation units Type DUPLEX 370 EC4.D; Placebo ventilation unit type DUPLEX 370
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Childhood Asthma; Allergy; House dust mites; Indoor air quality