Asthma
Conditions
Keywords
Odor, trigger, inflammation, nocebo
Brief 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
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.
Interventions
BEHAVIORALTherapeutic Suggestion
suggestions about potential beneficial effects of the odor are given
BEHAVIORALAsthmogenic Suggestion
suggestions about potential negative effects of the odor are given
OTHERPhenylethyl Alcohol odor
Over the course of 15 minutes, participants, receive 15 short sniffs of Phenylethyl Alcohol odor
Sponsors
KU Leuven
Research Foundation Flanders
Universitaire Ziekenhuizen KU Leuven
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* A physician diagnosis of asthma
Exclusion criteria
* FEV1 lower than 60% predicted * clinical condition other than asthma
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change from Baseline Exhaled Nitric Oxide to 24 hours after odor induction | baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction | Fraction of exhaled nitric oxide |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Forced Expiratory Volume at one second (FEV1) | baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction | Measured using Jaeger Masterscreen Spirometer, according to ERS-ATS guidelines |
| Worry | baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction | measured using worry Visual Analog Scales |
| Cortisol | baseline, immediately after odor induction, 2 hours after odor induction, at awakening, 30 min after awakening, 24 hours after odor induction | cortisol awakening response (AUC), and changes in cortisol (AUC) will be measured using saliva sampling |
| asthma symptoms | baseline, immediately after odor induction, 2 hours after odor induction, 24 hours after odor induction | measured using the Asthma Symptom Checklist |
| Change in Respiratory rate | change from baseline to 15 min odor presentation | respiratory rate (breaths/min) is recorded continuously, and changes between baseline and odor presentation periods will be analysed |
| change in Fraction of end-tidal carbon dioxide (FetCO2) | change from baseline to 15 min odor presentation | FetCO2 (plateau %CO2 in exhaled air) is recorded continuously, and changes between baseline and odor presentation periods will be analysed |
| Change in Heart rate and Heart Rate Variability (HRV) | change from baseline to 24 hours after odor induction | 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. |
Countries
Belgium
Outcome results
None listed