Recruiting

Cystic Fibrosis Carrier State

Sponsor:

University of Iowa

Code:

NCT06847256

Conditions

Carrier State

Heat Stroke

Dehydration

Eligibility Criteria

Sex: All

Age: 18 - 60

Healthy Volunteers: Not accepted

Interventions

Heat Challenge

Study Details

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

Carrier State

Heat Stroke

Dehydration

Study ID

NCT06847256

Start date

Nov 19, 2025

Status verified date

Apr, 2026

Completion date

Dec, 2026

Anticipated

Primary completion date

Dec, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 60

Healthy Volunteers: Not accepted

Inclusion Criteria:

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

Exclusion Criteria:

  • 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

Study Design

Enrollment

200 participants

Anticipated

Interventions and Outcome Measures

Arms

CF Carriers

Participants who have previously been genotyped as CF Carriers.

Controls

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

Interventions

Heat Challenge

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.

Primary outcome measure

  • Participant Scores for Temperature Sensitivity and Regulation Survey [ Time Frame: Baseline ]
  • Change in Weight [ Time Frame: Up to 45 minutes ]
  • Change in Sodium Concentration [ Time Frame: Up to 45 minutes ]
  • Change in Potassium Concentration [ Time Frame: Up to 45 minutes ]
  • Concentration of Sweat Chloride [ Time Frame: Up to 45 minutes ]
  • Final Score on Comfort Scale [ Time Frame: Up to 45 minutes ]
  • Final Score on Thermosensation Scale [ Time Frame: Up to 45 minutes ]

Central Contacts and Locations

Central contacts

Aaron Miller, PhD

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

Shelby L Francis, PhD

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

Locations

University of Iowa Health Care

Recruiting

Iowa City, Iowa, United States, 52242

Contacts

Shelby L Francis, PhD

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

Principal Investigator:

Aaron Miller, PhD

More Information

Sponsor

University of Iowa

Last update posted

Apr 27, 2026

Last verified

Apr, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by University of Iowa on 2026-04-27.