Investigating conditions causing breathlessness in athletes

ISRCTN	ISRCTN60543467
DOI	https://doi.org/10.1186/ISRCTN60543467
Secondary identifying numbers	EILO hos konditionsidrottare.

Submission date: 27/07/2020
Registration date: 24/08/2020
Last edited: 17/07/2023

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Respiratory

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Background and study aims
Exercise-induced dyspnea (shortness of breath) in athletes is common and is often attributed to asthma. However, all wheeze is not due to asthma and diagnosis and treatment should be based on careful clinical evaluation. Exercise-induced laryngeal obstruction (EILO) is an important differential diagnosis to asthma in athletes. In EILO, the larynx (voice box) is transiently obstructed during exercise resulting in decreased airflow and airway symptoms, typically with a sudden onset followed by rapid cessation when exercise is stopped. EILO is diagnosed with a continuous laryngoscopy during exercise (CLE) test, in which larynx is continuously visualized during peak exercise. This study aims to estimate the prevalence of EILO among athletes and to describe the natural history of EILO. Secondary aims of the study are to describe the prevalence of asthma and to what extent the conditions coexist.

Who can participate?
Healthy athletes at competitive level, 15-35 years of age

What does the study involve?
Participation in the study involves one or two visits at the Clinical Research Centre, where testing is done. Each visit includes a clinical examination by a physician, spirometry (lung function tests), asthma provocation test with a eucapnic voluntary hyperventilation test (EVH), skin prick test (only first visit), questionnaire, and continuous laryngoscopy during exercise (CLE) test.

What are the possible benefits and risks of participating?
The participants receive financial compensation of about £90 (SEK 1000). The pre-test requires exercise to exhaustion which may be uncomfortable for participants who do not frequently undertake high-intensity exercise. Oxygen uptake is measured using a mouthpiece and nose clip that might cause a little discomfort during exercise. Exposure to sub-zero temperatures is expected to cause short-lived cold-related symptoms. Blood sampling causes short-lived pain at the site of vein puncture. The lung function tests involve several large exhalations which may feel exhaustive in the moment.

Where is the study run from?
Clinical Research Centre, Östersund Hospital (Sweden)

When is the study starting and how long is it expected to run for?
April 2014 to November 2017

Who is funding the study?
1. VISARE NORR Fund, Northern Country Councils Regional Federation (Sweden)
2. Unit of Research, Education and Development, Region Jämtland Härjedalen (Sweden)

Who is the main contact?
1. Dr Tommie Irewall (public)
tommie.irewall@umu.se
2. Dr Nikolai Stenfors (scientific)
nikolai.stenfors@umu.se

Contact information

Dr Tommie Irewall
Public

Östersund Hospital
Kyrkgatan 16
Östersund
83183
Sweden

ORCID ID	0000-0002-8821-2352
Phone	+46 (0)63 153000
Email	tommie.irewall@umu.se

Dr Nikolai Stenfors
Scientific

Östersund Hospital
Kyrkgatan 16
Östersund
83183
Sweden

ORCID ID	0000-0002-1684-1301
Phone	+46 (0)63 153000
Email	nikolai.stenfors@umu.se

Study information

Study design	Single-center longitudinal cohort study
Primary study design	Observational
Secondary study design	Cohort study
Study setting(s)	Hospital
Study type	Screening
Participant information sheet	Not available in web format, please use the contact details to request a participant information sheet
Scientific title	Prevalence of exercise-induced laryngeal obstruction and asthma among athletes
Study objectives	Athletes have a high prevalence of exercise-induced laryngeal obstruction (EILO).
Ethics approval(s)	Approved 26/03/2015, Regional Ethical Review Board Umea (Samverkanshuset Universitetsområdet, 901 87 Umeå, Sweden; +46 (0)90 786 7252; epn@adm.umu.se), ref: Dnr 2015-43-31M
Health condition(s) or problem(s) studied	Prevalence of exercise-induced laryngeal obstruction (EILO) in athletes
Intervention	Participants undergo a clinical examination by the study physician, dynamic spirometry, eucapnic voluntary hyperventilation test, skin prick test, and continuous laryngoscopy during exercise test (CLE). CLE test includes running on a treadmill at incrementing speed to >90% maximum heart rate, while video recording larynx with a nasal fiberscope.
Intervention type	Other
Primary outcome measure	Prevalence and natural history of exercise-induced laryngeal obstruction (EILO), defined as laryngeal obstruction at glottic or supraglottic level using a visual scoring system, assessed with continuous laryngoscopy during exercise test (CLE), at the first and second visit (summer or winter season)
Secondary outcome measures	1. Current asthma, defined as a) physician-diagnosed asthma, and b) use of asthma medication in the last 12 months, evaluated by questionnaire at first visit 2. Bronchial hyperreactivity, defined as 10% decrease in FEV1 after EVH test, measured at the first and second visit (summer or winter season) 3. Allergy, defined as a) reaction with >2 mm wheal to skin prick test, and b) self-reported allergic symptoms, measured at first visit
Overall study start date	26/04/2014
Completion date	28/11/2017

Eligibility

Participant type(s)	Healthy volunteer
Age group	Mixed
Sex	Both
Target number of participants	100
Total final enrolment	111
Key inclusion criteria	1. Competitive athlete ( i.e. not at recreational level) 2. Age 15-35 years
Key exclusion criteria	1. Pregnancy 2. FEV1 <50% of expected value at spirometry 3. Blood pressure (mmHg) > 200 systolic or >100 diastolic at rest 4. Aortic aneurysm 5. Previous heart attack or stroke
Date of first enrolment	07/04/2015
Date of final enrolment	28/11/2017

Locations

Countries of recruitment

Sweden

Study participating centre

Clinical Research Centre, Östersund Hospital

Kyrkgatan 16
Östersund
831 83
Sweden

Sponsor information

Umeå University
University/education

Umeå
Umeå
SE-901 87
Sweden

Phone	+46 (0)90 786 50 00
Email	umea.universitet@umu.se
Website	http://www.umu.se/english

Funders

Funder type

Government

VISARE NORR Fund, Northern Country Councils Regional Federation

No information available

Unit of Research, Education and Development, Region Jämtland Härjedalen

No information available

Results and Publications

Intention to publish date	31/12/2021
Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Not expected to be made available
Publication and dissemination plan	Planned publications in peer-reviewed journals. Additional documents may be made available upon request.
IPD sharing plan	The data generated during and/or analysed during the current study are not expected to be made available due to a requirement in the ethical approval, where there is a statement that the data will not be shared with unauthorized persons. The data will be held in a server at Umeå University.

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article		01/06/2021	15/04/2021	Yes	No
Protocol file	In Swedish version 2	29/06/2020	30/08/2022	No	No
Other publications	Longitudinal follow-up	15/07/2023	17/07/2023	Yes	No

Additional files

ISRCTN60543467_Protocol_in Swedish_v2_29Jun2020.pdf: In Swedish

Editorial Notes

17/07/2023: Publication reference added.
30/08/2022: Protocol file uploaded.
15/04/2021: Publication reference added, the intention to publish date was changed from 30/10/2020 to 31/12/2021.
28/07/2020: Trial's existence confirmed by Regional Ethical Review Board Umea.