Effect of Genetic Differences on Levels of Water Disinfection Byproducts in Blood After Showering

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

This study will examine whether genetic differences among individuals affect blood levels of certain chemicals called DBPs after showering. Chemicals such as chlorine and ozone are used to kill germs in water. These chemicals may react with organic matter in the water and form other chemicals called disinfection byproducts, or DBPs. Although people are usually exposed to DBPs by drinking tap water, these chemicals may also penetrate the body during showering. This study will see whether the levels of DBPs after showering vary among individuals depending on differences in genes that code for enzymes called GSTT1, CYP2D6, and CYP2E1, which break down DBPs. This study, sponsored by the Centers for Disease Control and Prevention and the National Institutes of Health, is conducted at the University of Pittsburgh's Center for Clinical Pharmacology. Healthy adults between 18 and 45 years of age who do not smoke cigarettes and are not taking any medicines may be eligible for this study. Candidates are screened with a medical history and blood and urine tests. Participants are given a diary to record the foods they eat and how much water they drink during the 2 days before their study appointment. The following activities are scheduled on the appointment day: * Measurements of blood pressure, height, and weight, and pregnancy test for women * Questions about alcohol consumed and medications taken in the last 48 hours * Review of food and water diary * Interview for demographic information (name, address, date of birth, etc.) and other information, such as sex, height, weight. Subjects are also asked about anything, such as exercise, that might affect their breathing, since breathing problems are a rare side effect of chlorzoxazone, a drug used in this study. * Urine sample collection * Blood draw and insertion of a small catheter (plastic tube) to allow for additional blood draws during the test procedure without having repeated needle sticks * 10-minute shower in a private bathroom * Blood sample collection 10 minutes after the shower and again at 30 minutes after the shower * Dose of chlorzoxazone (a drug used to treat muscle pain) * Interview about subject's exposure to water * Light breakfast * Blood and urine collections 2 hours after the chlorzoxazone dose * Lunch * Observation for drug side effects for 2 hours, or longer if needed Seven blood samples totaling 75 milliliters (about 5 tablespoonfuls) of blood are collected during this study. The blood is tested for chemicals called trihalomethanes to see how they are broken down. The urine samples are tested for chemicals called haloacetic acids, which are found in tap water after it has been treated with chlorine.

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Last update posted Mar 4, 2021 · Synced Sep 11, 2026

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