Iodine-129 Tracer Method for Investigating Human Iodine Metabolism

NCT02955745 | Completed

• 1 other identifier: Iodine-129
• Study Type: observational
• Target: 8
• Locations: 1 country
• Sites: 1

Brief Summary

Current iodine requirements defined for pregnancy and lactation are rough factorial estimates extrapolated from older studies in adults that used radioactive iodine tracers. To ensure optimal thyroid function in these vulnerable groups, a tracer method that could be safely used to accurately define iodine requirements would be valuable. Iodine-129 (129I), a long-lived semi-stable isotope with no health risks, could be used as a tracer, but the analytic challenges are formidable. However, we have developed an ICP-MS method to measure pp-billion (10-9) to pp-trillion (10-12) quantities of 129I in biological samples. In this project we will perform a study in which iodine-replete adult subjects will consume an oral dose of 129I. We will quantify 129I kinetic patterns in plasma, urine and stools after the oral dose, and use these data to derive tracer absorption, retention and excretion rates. This trial will allow us to define optimized procedures for the routine application of this method to assess iodine metabolism in humans. The use of 129I may prove to be a breakthrough technique to safely assess iodine metabolism and requirements in pregnant/lactating women in order to ensure healthy thyroid function in these age groups.

Conditions

Healthy Volunteers

Outcome Measures

Primary Outcomes (1)

• 129I kinetics

  129I-tracer concentration in plasma (both in its inorganic and organic form), urine, and stool samples collected prior and following administration of a single physiological oral 129I dose in order to derive rates of absorption, retention, and excretion of dietary iodine

  8 days

Secondary Outcomes (3)

• Thyroid function

  1 day

• Dietary iodine

  10 days

• Minimal sampling requirements

  10 days

Interventions

Iodine-129 OTHER

The present study is an observational study and does not therefore include an investigational product in the proper sense because the used tracer (semi-stable iodine isotope) has no physiological effect on the participants. 129I will be used as tracer to measure appearance in plasma, urine and stools after the oral administered of the 129I-tracer.

Also known as: 129I

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Generally healthy, iodine-replete males and non-pregnant, non-lactating females, who are between 18 and 45 years old, whose body weight is less than 80 kg and BMI between 19-27.5 kg/m2, who regularly consume iodized salt, who have signed the informed consent, and who have good knowledge of the English language. They will serve as an iodine-sufficient population with normal iodine metabolism.

You may qualify if:

• Aged between 18 and 45 years
• Body weight \<80 kg and BMI 19-27.5
• Current use of iodized salt at home
• Signed informed consent
• Good knowledge of English language

You may not qualify if:

• Inadequate iodine status (defined as UIC \<80 µg/L or \>300 µg/L and assessed during screening from 10 urine spot samples)
• Exposure to iodine-containing X-ray/ computed tomography contrast agent
• Use of iodine-containing disinfectants (betadine)
• History of thyroid disease (according to the participants own statement)
• Any metabolic, gastrointestinal or chronic disease such as diabetes, hepatitis, hypertension, or cancer (according to the participants own statement)
• Chronic use of medications (except for contraceptives)
• Use of iodine containing supplements within 6 months prior to study start
• Pregnancy (according to the participants own statement but confirmed by a pregnancy test with the first urine spot sample from screening)
• Breast feeding
• Vegan or vegetarian diet
• Drug abuse
• Extensive alcohol intake, defined as more than 3 (men) or 2 (women) standard drinks per day (i.e. 3dl beer, 1dl wine, 3-4cl liquor), with less than 2 days per week without alcohol consumption
• Earlier participation in any other clinical study within the last 30 days

Sponsors & Collaborators

• Swiss Federal Institute of Technology: lead
• Swiss Federal Food Safety and Veterinary Office: collaborator
• University Hospital, Zürich: collaborator

Study Sites (1)

ETH Zurich, Laboratory of Human Nutrition

Zurich, 8092, Switzerland

Location

MeSH Terms

Interventions

Iodine-129

Study Officials

• Michael B Zimmermann, MD

  ETH Zurich

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: OTHER
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof. dr. med.

Study Record Dates

• First Submitted: November 3, 2016
• First Posted: November 4, 2016
• Study Start: November 1, 2016
• Primary Completion: January 17, 2017
• Study Completion: January 17, 2017
• Last Updated: June 12, 2017

Record last verified: 2017-06

Locations

CH (1)