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

Completed

• Conditions: Iodine Deficiency
• Interventions: Other: No intervention

• Registration Number: NCT03731312
• Lead Sponsor: Swiss Federal Institute of Technology

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study Start: 2018-10-01
• Study First Submitted: 2018-10-01
• Study First Submitted QC: 2018-11-05
• Study First Posted: 2018-11-06
• Primary Completion: 2021-05-04
• Study Completion: 2021-05-04
• Status Verified: 2021-09
• Last Update Submitted: 2021-09-10
• Last Update Posted: 2021-09-14

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Female
• Target Recruitment: 206

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 & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Study group	No intervention	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.

Primary Outcome Measures

Name	Time	Method
Estimated daily urinary iodine excretion	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

Secondary Outcome Measures

Name	Time	Method
Measured daily iodine excretion	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
Thyroid function test TSH	1 day	TSH concentration (mU/L) measured in dried blood spots
Thyroid function test total T4	1 day	Total T4 concentration (nmol/L) measured in dried blood spots
Thyroid function test Tg	1 day	Tg concentration (µg/L) measured in dried blood spots

Trial Locations

Locations (1)

ETH Zurich; 🇨🇭 Zürich, Switzerland