Exploring a Common Genetic Risk Factor for Heat Stroke and Dehydration
University of Iowa
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.
Eligibility
- Age range
- 18–60 years
- Sex
- All
- Healthy volunteers
- No
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
Interventions
- ProcedureHeat 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.
Location
- University of Iowa Health CareIowa City, Iowa