Background: The most common method for determining a population’s iodine status is median Urinary Iodine Concentration (UIC) determined in spot urine samples. Urinary Iodine Excretion (UIE) derived from 24-hour urine collections is likely to provide a more accurate measure of iodine status as it captures variations in excretion over the whole day, however few surveys have utilised 24-hour urine collections to determine UIC.
Aims: To assess UIC (μg/L) and UIE (μg/day) in 24-hour urine collections obtained from a sample of Victorian primary schoolchildren and to determine whether the sample is iodine sufficient, when compared with World Health Organisation (WHO) guidelines.
Methods: As part of a cross-sectional study, 24-hour urine samples were collected from primary school children aged 5-12 years from 42 schools across Victoria, Australia between 2010-2013.
Results: The sample included 650 children, 359 boys and 291 girls (mean (SD) age 9.3(1.8)years). The mean urine volume was 873(424)mL. The mean UIE and median (IQR) UIC were 104(54) μg/day and 124(83,172)μg/L respectively. Boys were found to have significantly higher mean UIE compared to girls (112 vs. 93, P<0.0001). The median UIC of the children falls between 100-199μg/L, indicating adequate iodine status. Using UIC 36% of participants were classified as having a UIC less than 100μg/L, with only 8% less than 50μg/L.
Conclusion: In comparison with WHO guidelines for assessing the iodine status of a population, this group of Victorian school children is iodine sufficient.
Funding Sources: Australian Postgraduate Award, National Heart Foundation of Australia, Helen MacPherson Smith Trust Fund.