Study of Risk Factors for the Occurrence and Severity of Exertional Heatstroke in the Military Environment (EXPLO-CCE)

Although the circumstances of onset and management of exertional heatstroke have been identified for several years, its pathophysiology remains imperfectly understood. Exertional heatstroke is the result of both extrinsic (i.e. environmental) and intrinsic (i.e. individual) contributing factors.

Extrinsic factors are well known (high ambient temperature and hygrometry, poorly "breathable" clothing, intense and prolonged physical effort) but some of them may be observed in milder conditions. In the French Armed Forces, 25% of the exertional heatstrokes that have been reported between 2005 and 2011 occurred below 17°C.

Intrinsic factors, on the other hand, are numerous and less consensual, partly because of the imperfect knowledge of exertional heatstroke physiopathology. Potential factors include a thermoregulatory defect (inability to maintain a temperature plateau during an effort) and several genetic mutations may also contribute to explain a propensity to present an exertional heatstroke. While exertional heatstroke is clearly not a monogenic pathology, the association of several polymorphisms could contribute to this vulnerability. Among the genes that have been explored, mutations in ryanodine receptor type 1 (RyR 1), calsequestrin-1 or angiotensin-1 converting enzyme (ACE) appear to be potential candidates. However, it is very likely that other polymorphisms may be involved, such as: genes involved in sports performance and exercise rhabdomyolysis, in the inflammatory cascade, permeability of the digestive epithelial barrier, adenosine receptors and susceptibility to anxiety.

Finally, motivation is a mixed factor often claimed to be involved in exertional heatstroke but has never been quantified and needs to be objectified.

To date, none of these hypotheses has been clearly assessed by comparing patients who experienced exertional heatstroke to healthy subjects.

Study Overview

Study Type

Observational

Enrollment (Anticipated)

300

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

      • Brétigny-sur-Orge, France, 91223
        • Not yet recruiting
        • Institut de Recherche Biomédicale des Armées
        • Contact:
      • Marseille, France, 13384
      • Paris, France, 75005

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years to 43 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

The study population will be composed of patients who are experiencing or who have experienced exertional heatstroke (heatstroke group) and people who have not (control group).

Description

Inclusion Criteria:

  • Active military
  • Between 18 and 45 years old
  • Ability to the walk/run test

Exclusion Criteria:

  • Ongoing drug treatment (for the control group only),
  • BMI greater than or equal to 30,
  • Contraindication to the ingestion of a core temperature capsule

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Case-Control
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Exertional heatstroke group
Patients presenting or having presented exertional heatstroke.
A saliva sample will be collected before physical exercise.
The participant will fill in questionnaires relative to his heath status and psychological and motivational resource questionnaires before physical exercise.
The participant will ingest a capsule before physical exercise in order to continuously monitor core temperature during physical exercise.
The participant will perform a walk/run test.
Heart rate will be monitored during physical exercise thanks to a chest belt.
Heart rate will be monitored during physical exercise thanks to an ingestible core temperature capsule.
Control group
Healthy people who never experienced exertional heatstroke.
A saliva sample will be collected before physical exercise.
The participant will fill in questionnaires relative to his heath status and psychological and motivational resource questionnaires before physical exercise.
The participant will ingest a capsule before physical exercise in order to continuously monitor core temperature during physical exercise.
The participant will perform a walk/run test.
Heart rate will be monitored during physical exercise thanks to a chest belt.
Heart rate will be monitored during physical exercise thanks to an ingestible core temperature capsule.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Difference of the frequency of CYP24A1 gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of CYP24A1 gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of DRD2 gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of DRD2 gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of BDNF gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of BDNF gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of COMT gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of COMT gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of FAAH gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of FAAH gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of TPH2 gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of TPH2 gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of GRIN2B gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of GRIN2B gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of PER3 gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of PER3 gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of TNF-a gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of TNF-a gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of IL-6 gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of IL-6 gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of IL1B gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of IL1B gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of HSPA1B gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of HSPA1B gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)
Difference of the frequency of TLR4 gene polymorphisms between the heatstroke group and the control group
Time Frame: At enrollment (day 1)
The frequency of TLR4 gene polymorphisms will calculated in each group by dividing the number of participants who present the polymorphism by the total number of participants in the group.
At enrollment (day 1)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 2, 2020

Primary Completion (Anticipated)

November 1, 2024

Study Completion (Anticipated)

November 1, 2024

Study Registration Dates

First Submitted

October 13, 2020

First Submitted That Met QC Criteria

October 13, 2020

First Posted (Actual)

October 20, 2020

Study Record Updates

Last Update Posted (Actual)

March 9, 2021

Last Update Submitted That Met QC Criteria

March 8, 2021

Last Verified

March 1, 2021

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2019PBMD03
  • 2020-A01967-32 (Other Identifier: IDRCB)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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