Study of Risk Factors for the Occurrence and Severity of Exertional Heatstroke in the Military Environment

Recruiting

• Conditions: Heat Stroke
• Interventions: Other: Saliva collection; Behavioral: Questionnaires; Other: Ingestible core temperature capsule intake; Other: Physical exercise; Other: Heart rate monitoring; Other: Core temperature monitoring

• Registration Number: NCT04593316
• Lead Sponsor: Direction Centrale du Service de Santé des Armées

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2020-10-13
• Study First Submitted QC: 2020-10-13
• Study First Posted: 2020-10-20
• Study Start: 2020-11-02
• Status Verified: 2021-03
• Last Update Submitted: 2021-03-08
• Last Update Posted: 2021-03-09
• Primary Completion: 2024-11
• Study Completion: 2024-11

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 300

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 & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Exertional heatstroke group	Core temperature monitoring	Patients presenting or having presented exertional heatstroke.
Control group	Ingestible core temperature capsule intake	Healthy people who never experienced exertional heatstroke.
Exertional heatstroke group	Questionnaires	Patients presenting or having presented exertional heatstroke.
Exertional heatstroke group	Heart rate monitoring	Patients presenting or having presented exertional heatstroke.
Control group	Saliva collection	Healthy people who never experienced exertional heatstroke.
Control group	Physical exercise	Healthy people who never experienced exertional heatstroke.
Exertional heatstroke group	Saliva collection	Patients presenting or having presented exertional heatstroke.
Exertional heatstroke group	Ingestible core temperature capsule intake	Patients presenting or having presented exertional heatstroke.
Exertional heatstroke group	Physical exercise	Patients presenting or having presented exertional heatstroke.
Control group	Questionnaires	Healthy people who never experienced exertional heatstroke.
Control group	Heart rate monitoring	Healthy people who never experienced exertional heatstroke.
Control group	Core temperature monitoring	Healthy people who never experienced exertional heatstroke.

Primary Outcome Measures

Name	Time	Method
Difference of the frequency of FAAH gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of GRIN2B gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of BDNF gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of CYP24A1 gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of COMT gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of TPH2 gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of DRD2 gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of PER3 gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of IL1B gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of HSPA1B gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of TNF-a gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of TLR4 gene polymorphisms between the heatstroke group and the control group	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.
Difference of the frequency of IL-6 gene polymorphisms between the heatstroke group and the control group	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.

Trial Locations

Locations (3)

Hôpital d'Instruction des Armées Laveran; 🇫🇷 Marseille, France

Institut de Recherche Biomédicale des Armées; 🇫🇷 Brétigny-sur-Orge, France

Ecole du Val-de-Grâce; 🇫🇷 Paris, France