Advantages of collecting multiple urinary iodine concentrations when assessing iodine status of a population

Area of Science:

• Nutritional biochemistry
• Pediatric health assessment
• Biomarker variability analysis

Background:

• Urinary iodine concentration (UIC) is a key indicator of iodine status.
• High variability in single UIC measurements can obscure accurate cohort assessment.
• Standard methods may not fully capture individual iodine status due to diurnal and day-to-day fluctuations.

Purpose of the Study:

• To determine the impact of collecting multiple urine samples on the variability of UIC.
• To enhance the accuracy of iodine status assessment in pediatric cohorts.
• To investigate the optimal number of samples for reliable iodine status evaluation.

Main Methods:

• Study involved 51 children aged 2-3 years and 30 children aged 8-10 years in Australia.
• Four urine samples were collected from each child.
• Urine samples were analyzed using ammonium persulphate digestion and the Sandell-Kolthoff reaction.
• Analysis of variance techniques were employed to assess the effect of sample number on UIC variability.

Main Results:

• Median UICs were 223.3 μg/L (2-3 years) and 141 μg/L (8-10 years).
• Collecting multiple samples significantly reduced the coefficient of variance (CV) for UIC.
• CV reduction ranged from 35.6% to 39.7% for younger children and 24.7% to 34.7% for older children with 2-4 samples.

Conclusions:

• Collecting multiple urine samples improves the accuracy of iodine status assessment in children.
• This approach provides a more reliable reflection of cohort iodine status compared to single samples.
• Practicality and cost-effectiveness of multiple sample collection warrant consideration for widespread implementation.