Variability of Daily Iodine Intake: The Effects of Intra- and Inter-individual Variability in Iodine Nutrition Studies (VIOLET)

September 10, 2021 updated by: Swiss Federal Institute of Technology

Variability of Daily Iodine Intake: The Effects of Intra- and Inter-individual Variability on Estimated Intake in Iodine Nutrition Studies

Iodine status in populations is assessed using urinary iodine concentration (UIC) measured in spot urine samples. The iodine intake is classified as deficient, sufficient, or excessive iodine based on the median UIC (mUIC). However, this approach has limitations, as it does not quantify the prevalence of individuals with habitually deficient or excess iodine intakes. The EAR cut-point method has the potential to quantify prevalence of iodine deficiency and excess. However, little is known about the effects of the inter- and intra-individual variance of UIC.

The aim of the study is to quantify the intra-individual variability in dietary iodine intake. The overall goal is to estimate the prevalence of iodine deficiency and excess in the study population and propose sample size recommendations for future iodine nutrition population studies. The results will provide evidence guiding international recommendations for iodine nutrition studies.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Actual)

206

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 44 years (ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Sampling Method

Non-Probability Sample

Study Population

Healthy women of reproductive age and residents of Switzerland since at least 12 months

Description

Inclusion Criteria:

  • Non-pregnant
  • Non-lactating
  • Non-smoking
  • Residence in Switzerland ≥12 months
  • Generally healthy
  • No family history of goiter
  • No exposure to iodine containing contrast agents during the last 12 months - Informed consent given

Exclusion Criteria:

  • Participant is not able to understand the study information or procedure, e.g. due to linguistic barriers

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Study group
We will collect two repeated spot urine samples, a DBS sample and obtain weight in all 600 study participants. In a randomly selected subsample (n=200) a third repeat spot urine sample and one 24 h urine will additionally be collected.
Other: No intervention
This is an observational study and no interventions will be administered.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Estimated daily urinary iodine excretion
Time Frame: 7 days
Estimated urinary iodine excretion (µg/day) will be obtained from urinary iodine concentration (UIC) and urinary creatinine concentration (UCC) measured in two repeat spot urine samples collected within 7 days
7 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Measured daily iodine excretion
Time Frame: 1 day
Measured daily iodine excretion (µg/day) will be obtained from urinary iodine concentration (UIC) and urine volume in a 24 h urine collection
1 day
Thyroid function test TSH
Time Frame: 1 day
TSH concentration (mU/L) measured in dried blood spots
1 day
Thyroid function test total T4
Time Frame: 1 day
Total T4 concentration (nmol/L) measured in dried blood spots
1 day
Thyroid function test Tg
Time Frame: 1 day
Tg concentration (µg/L) measured in dried blood spots
1 day

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Swiss Federal Institute of Technology

Investigators

  • Principal Investigator: Jessica Rigutto-Farebrother, PhD, ETH Zurich

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ACTUAL)

October 1, 2018

Primary Completion (ACTUAL)

May 4, 2021

Study Completion (ACTUAL)

May 4, 2021

Study Registration Dates

First Submitted

October 1, 2018

First Submitted That Met QC Criteria

November 5, 2018

First Posted (ACTUAL)

November 6, 2018

Study Record Updates

Last Update Posted (ACTUAL)

September 14, 2021

Last Update Submitted That Met QC Criteria

September 10, 2021

Last Verified

September 1, 2021

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • VIOLET (Boehringer Ingelheim)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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