AsthmaNCT02624362
The Effect of Odors on Asthma Symptoms
A study testing Therapeutic Suggestion, Asthmogenic Suggestion and Phenylethyl Alcohol odor in people with Asthma, run by Universitaire Ziekenhuizen KU Leuven at 1 site in Belgium.
Trial summary
An extended replication of Jaen \& Dalton (2014), the investigators aim to investigate the role of odors and associated trigger beliefs on symptom perception and airway inflammation in individuals with asthma Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Asthma
- What is being tested?
- Therapeutic Suggestion, Asthmogenic Suggestion and Phenylethyl Alcohol odor
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 48 participants
- Where
- 1 siteBelgium
- Study dates
- Aug 2015to Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- A physician diagnosis of asthma
Who cannot join
- FEV1 lower than 60% predicted
- clinical condition other than asthma
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
About this study
Official title: The Effect of Suggestion of Harmful/Beneficial Effects of Odors on Asthma Symptoms
An extended replication of Jaen \& Dalton (2014), the investigators aim to investigate the role of odors and associated trigger beliefs on symptom perception and airway inflammation in individuals with asthma
Read the detailed description
Participants with asthma are randomly assigned to a 15-min (phenylethyl alcohol) odor inhalation, accompanied by either an asthmogenic suggestion (nocebo), or a therapeutic suggestion (placebo). Airway inflammation, lung function, and asthma symptoms are measured in response to the odor/suggestion, up to 24 hours after odor inhalation. The investigators are also measuring worry and heart rate variability as potential mediators of the response.
- Conditions
- Asthma
- Being tested
- Therapeutic Suggestion, Asthmogenic Suggestion, Phenylethyl Alcohol odor
- Keywords
- Odor, trigger, inflammation, nocebo
- Medical subject headings
- Asthma, Inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Therapeutic SuggestionBehavioural
Also called placebo suggestion, positive treatment belief induction
suggestions about potential beneficial effects of the odor are given
Asthmogenic SuggestionBehavioural
Also called nocebo suggestion, negative treatment belief
suggestions about potential negative effects of the odor are given
Phenylethyl Alcohol odorOther
Over the course of 15 minutes, participants, receive 15 short sniffs of Phenylethyl Alcohol odor
| Study group | Role | What they receive |
|---|---|---|
| Odor+ Positive belief | Experimental | Participants receive 15 minute odor presentation (Phenylethyl Alcohol odor) accompanied by the suggestion that this odor improves asthma symptoms (therapeutic suggestion) Receives: Behavioral: Therapeutic Suggestion; Other: Phenylethyl Alcohol odor |
| Odor + Negative belief | Experimental | Participants receive 15 minute odor presentation (Phenylethyl Alcohol odor) accompanied by the suggestion that this odor worsens asthma symptoms (asthmogenic suggestion) Receives: Behavioral: Asthmogenic Suggestion; Other: Phenylethyl Alcohol odor |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from Baseline Exhaled Nitric Oxide to 24 hours after odor induction
Fraction of exhaled nitric oxide
Measured: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction
Secondary outcomes (7)
asthma symptoms
measured using the Asthma Symptom Checklist
Measured: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction
Forced Expiratory Volume at one second (FEV1)
Measured using Jaeger Masterscreen Spirometer, according to ERS-ATS guidelines
Measured: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction
Worry
measured using worry Visual Analog Scales
Measured: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction
Cortisol
cortisol awakening response (AUC), and changes in cortisol (AUC) will be measured using saliva sampling
Measured: baseline, immediately after odor induction, 2 hours after odor induction, at awakening, 30 min after awakening, 24 hours after odor induction
Change in Heart rate and Heart Rate Variability (HRV)
24 hour heart rate data will be recorded using an ambulatory ECG monitor, and analyzed in 1 hour epochs, extracting mean of successive differences (MSD) as a variable of interest.
Measured: change from baseline to 24 hours after odor induction
Change in Respiratory rate
respiratory rate (breaths/min) is recorded continuously, and changes between baseline and odor presentation periods will be analysed
Measured: change from baseline to 15 min odor presentation
change in Fraction of end-tidal carbon dioxide (FetCO2)
FetCO2 (plateau %CO2 in exhaled air) is recorded continuously, and changes between baseline and odor presentation periods will be analysed
Measured: change from baseline to 15 min odor presentation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Dec 2015 (estimated)
- Study startAug 2015
- Primary completionJul 2026 (estimated)
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for AsthmaStudies of the same condition, open and under way.
- More trials run by Universitaire Ziekenhuizen KU LeuvenThe 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 48 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universitaire Ziekenhuizen KU Leuven
- Sponsor type
- University, hospital or other
- Collaborators
- KU Leuven, Research Foundation Flanders
- Responsible party
- Sponsor
- Investigators
- Thomas Janssens, PhD, Principal investigator, KU Leuven
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02624362
- Sponsor's protocol ID
- S57940
- Status last verified
- Jul 2024
- First submitted
- 1 Dec 2015
- Last updated
- 3 Jul 2024
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Jul 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Suggestion of Harmful/Beneficial Effects of Odors on Asthma Symptoms
- ClinicalTrials.gov ID
- NCT02624362
- Acronym / sponsor ID
- S57940
- Conditions
- Asthma
- Keywords
- Odor, trigger, inflammation, nocebo
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 48 participants (estimated)
- Lead sponsor
- Universitaire Ziekenhuizen KU LeuvenUniversity, hospital or other
- Collaborators
- KU Leuven, Research Foundation Flanders
- Study start
- Aug 2015 (actual)
- Primary completion
- Jul 2026 (estimated)
- Study completion
- Dec 2026 (estimated)
- First posted
- 8 Dec 2015 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
An extended replication of Jaen \& Dalton (2014), the investigators aim to investigate the role of odors and associated trigger beliefs on symptom perception and airway inflammation in individuals with asthma
Detailed description
Participants with asthma are randomly assigned to a 15-min (phenylethyl alcohol) odor inhalation, accompanied by either an asthmogenic suggestion (nocebo), or a therapeutic suggestion (placebo). Airway inflammation, lung function, and asthma symptoms are measured in response to the odor/suggestion, up to 24 hours after odor inhalation. The investigators are also measuring worry and heart rate variability as potential mediators of the response.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Odor+ Positive belief | Experimental | Behavioral: Therapeutic Suggestion, Other: Phenylethyl Alcohol odorParticipants receive 15 minute odor presentation (Phenylethyl Alcohol odor) accompanied by the suggestion that this odor improves asthma symptoms (therapeutic suggestion) |
| Odor + Negative belief | Experimental | Behavioral: Asthmogenic Suggestion, Other: Phenylethyl Alcohol odorParticipants receive 15 minute odor presentation (Phenylethyl Alcohol odor) accompanied by the suggestion that this odor worsens asthma symptoms (asthmogenic suggestion) |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- A physician diagnosis of asthma
Key exclusion criteria (2 listed)
- FEV1 lower than 60% predicted
- clinical condition other than asthma
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Therapeutic SuggestionAlso: placebo suggestion, positive treatment belief inductionsuggestions about potential beneficial effects of the odor are given | Behavioural | Odor+ Positive belief |
| Asthmogenic SuggestionAlso: nocebo suggestion, negative treatment beliefsuggestions about potential negative effects of the odor are given | Behavioural | Odor + Negative belief |
| Phenylethyl Alcohol odorOver the course of 15 minutes, participants, receive 15 short sniffs of Phenylethyl Alcohol odor | Other | Odor + Negative belief, Odor+ Positive belief |
Primary outcome
Change from Baseline Exhaled Nitric Oxide to 24 hours after odor induction
Time frame: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction
Fraction of exhaled nitric oxide
7 secondary outcomes
asthma symptoms
Time frame: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction
Forced Expiratory Volume at one second (FEV1)
Time frame: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction
Worry
Time frame: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction
Cortisol
Time frame: baseline, immediately after odor induction, 2 hours after odor induction, at awakening, 30 min after awakening, 24 hours after odor induction
Change in Heart rate and Heart Rate Variability (HRV)
Time frame: change from baseline to 24 hours after odor induction
Change in Respiratory rate
Time frame: change from baseline to 15 min odor presentation
change in Fraction of end-tidal carbon dioxide (FetCO2)
Time frame: change from baseline to 15 min odor presentation
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Jul 2024.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Thomas Janssens, PhD principal investigator
KU Leuven
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Therapeutic Suggestion, Asthmogenic Suggestion and Phenylethyl Alcohol odor in people with Asthma, run by Universitaire Ziekenhuizen KU Leuven at 1 site in Belgium.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 3 Jul 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change from Baseline Exhaled Nitric Oxide to 24 hours after odor induction (time frame: baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Jul 2024; AzTrials last refreshed its copy on 7 Nov 2026.