Genetic Risk Factor for Heat Stroke

NCT06847256 | Recruiting

• 1 other identifier: 202308319
• Study Type: observational
• Target: 200
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this observational study is to examine the effect of the Cystic Fibrosis (CF) Carrier state on the risk for dehydration and other CF-specific fluid-and-electrolyte disorders in male and female adults. The primary aim of the study is to estimate the risk of electrolyte disorders attributable to the CF carrier state in a genotyped cohort. This will be accomplished with two smaller projects- Aim 1 and Aim 2. Aim 1 will consist of 100 CF Carriers and 100 age- and sex-matched controls. Participants in this aim will be asked to complete a Participant Info and Temperature Survey consisting of questions about race, ethnicity, medical history, and how they experience heat. Aim 2 will consist of a subset of 25 CF Carriers and 25 age- and sex-matched controls from Aim 1. Participants in this aim will be scheduled for a visit to complete a heat challenge. At this visit, they will also complete the Participant Info and Temperature Survey. They will also sit in a sauna at 62 - 63 degrees Celsius for 45 minutes.

Conditions

Heat Stroke; Dehydration; Carrier State

Outcome Measures

Primary Outcomes (7)

• Participant Scores for Temperature Sensitivity and Regulation Survey

  Individual and composite scores for 5 components of the Temperature Sensitivity Survey (Heat- and Activity-Induced Autonomic Thermoregulation; Heat-Induced Behavioral Thermoregulation; Heat Perception; and Heat- and Activity-Induced Fatigue). For these 5 components, there are a total of 25 questions. All questions are on a 7-point scale, with the highest representing the most sensitive to heat and the lowest being the least sensitive. We will add up the scores for each question to arrive at a composite score for each component and the component scores will be added to arrive at a total score. Scores will be compared between groups.

  Baseline

• Change in Weight

  Weight will be measured in kilograms pre- and post-heat challenge. We will compare change in weight between groups.

  Up to 45 minutes

• Change in Sodium Concentration

  Sodium concentration will be measured pre- and post-heat challenge by blood draw and urine sample. Sodium concentration will be compared between groups.

  Up to 45 minutes

• Change in Potassium Concentration

  Potassium concentration will be measured pre- and post-heat challenge by blood draw and urine sample. Potassium concentration will be compared between groups.

  Up to 45 minutes

• Concentration of Sweat Chloride

  Sweat chloride will be measured pre- and post-heat challenge by sweat collection. Sweat chloride will be compared between groups.

  Up to 45 minutes

• Final Score on Comfort Scale

  Participants will rate their level of comfort on a scale of 1-4 at the end of the heat challenge. Scores will be compared between groups.

  Up to 45 minutes

• Final Score on Thermosensation Scale

  Participants will rate their level of thermosensation on a scale of 1-7 at the end of the heat challenge. Scores will be compared between groups.

  Up to 45 minutes

Study Arms (2)

CF Carriers

Participants who have previously been genotyped as CF Carriers.

Procedure: Heat Challenge

Controls

Participants who have previously been genotyped as controls and are age- and sex-matched to a CF Carrier.

Procedure: Heat Challenge

Interventions

Heat Challenge PROCEDURE

Participants will be asked to arrive well-hydrated and to refrain from exercise, alcohol, caffeine, and smoking for 24 hours prior to the visit. Height, weight, blood pressure, and body fat percentage will be measured. Blood (15.5 ml) and urine will be collected. Participants will wear a heart rate monitor and sit in a heat chamber at 62-63 degrees Celsius for 45 minutes. Heart rate will be measured continuously. Body temperature and a self-report of their comfort (1-4 scale) and thermosensation (1-7 scale) will be measured before the challenge, every 15 minutes during the challenge, and after the challenge. During the challenge, a sample of sweat will be collected to measure electrolyte loss. Participants will consume 16 ounces of water at their own pace during the 45 minutes. If they become too uncomfortable to continue or their body temperature rises above 39 degrees Celsius, the challenge will be stopped. All baseline measures except body fat percentage will be measured again.

CF Carriers; Controls

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Individuals who have previously been genotyped as CF Carriers or Controls.

You may qualify if:

• Previously genotyped as a CF carrier or control
• Comfortable speaking/reading English

You may not qualify if:

• Previously genotyped as a CF patient
• Diagnosis of Type 1 or Type 2 diabetes
• History of heart attack, stroke, heart failure, or atherosclerosis
• Currently pregnant
• Currently taking beta blockers or diuretics
• Prisoner status
• Unable to provide own written informed consent

Sponsors & Collaborators

• University of Iowa: lead

Study Sites (1)

University of Iowa Health Care

Iowa City, Iowa, 52242, United States

RECRUITING

MeSH Terms

Conditions

Heat Stroke; Dehydration

Condition Hierarchy (Ancestors)

Heat Stress Disorders; Wounds and Injuries; Water-Electrolyte Imbalance; Metabolic Diseases; Nutritional and Metabolic Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Aaron Miller, PhD

  University of Iowa

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Aaron Miller, PhD

CONTACT

(319) 335-3053; aaron-miller@uiowa.edu

Shelby L Francis, PhD

CONTACT

319-678-8037; shelby-francis@uiowa.edu

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Research Assistant Professor

Study Record Dates

• First Submitted: February 14, 2025
• First Posted: February 26, 2025
• Study Start: November 19, 2025
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: April 27, 2026

Record last verified: 2026-04

Locations

US (1)