The assessment of iodine status – populations, individuals and limitations

Wainwright, Patrick; Cook, Paul

doi:10.1177/0004563218774816

Cited by 34 publications

(34 citation statements)

References 60 publications

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“…Many studies have used UIC to assess iodine status, but few studies have involved the reliability and variability of UIC in assessing the iodine status of a population or an individual (2,9) . In this instance, our study provided a referable set of data by collecting diet and 24-h urine samples twelve times from a small population of twenty-four participants to assess variation in iodine intake and excretion, not just urinary iodine concentrations.…”

Section: Discussionmentioning

confidence: 99%

Intra-individual and inter-individual variations in iodine intake and excretion in adult women: implications for sampling

et al. 2019

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Iodine intake and excretion vary widely; however, these variations remain a large source of geometric uncertainty. The present study aims to analyse variations in iodine intake and excretion and provide implications for sampling in studies of individuals or populations. Twenty-four healthy women volunteers were recruited for a 12-d sampling period during the 4-week experiment. The duplicate-portion technique was used to measure iodine intake, while 24-h urine was collected to estimate iodine excretion. The mean intra-individual variations in iodine intake, 24-h UIE (24-h urinary iodine excretion) and 24-h UIC (24-h urinary iodine concentration) were 63, 48 and 55 %, respectively, while the inter-individual variations for these parameters were 14, 24 and 32 %, respectively. For 95 % confidence, approximately 500 diet samples or 24-h urine samples should be taken from an individual to estimate their iodine intake or iodine status at a precision range of ±5%. Obtaining a precision range of ±5% in a population would require twenty-five diet samples or 150 24-h urine samples. The intra-individual variations in iodine intake and excretion were higher than the inter-individual variations, which indicates the need for more samples in a study on individual participants.

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Section: Discussionmentioning

confidence: 99%

Intra-individual and inter-individual variations in iodine intake and excretion in adult women: implications for sampling

et al. 2019

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“…It causes complications with the woman’s reproductive cycle, complications with pregnancy, irreversible congenital anomalies of new-borns and thyroid dysfunction in adults. To ensure that everyone has a sufficient intake of iodine, The World Health Organization (WHO) and United Nations International Children’s Emergency Fund (UNICEF) recommend universal salt iodization as a global strategy ( 4 – 8 ).…”

Section: Introductionmentioning

confidence: 99%

Analytical evaluation of the new Seal Autoanalyzer 3 High Resolution for urinary iodine determination

Vidranski

Franceschi

Krilić³

et al. 2019

Biochem. med. (Online)

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Introduction: The aim of the study was to evaluate the analytical performance of the new colorimetric, automatic analyser, Seal AutoAnalyzer 3 High Resolution (Seal AA3 HR) (Seal Analytical, Wisconsin, USA) for urinary iodine measurement. Materials and methods: This study included testing of several analytical features of the method involving: imprecision (within-run %CVr, between- run %CVb and total laboratory precision %CVl), measurement uncertainty, carryover, linearity and method comparison, with 70 urine samples including the measuring range (20 - 700 μg/L). Results: Within-run, %CVb and %CVl of two control levels were 2.03% and 3.04%, 0.51% and 2.61%, and 2.09% and 4.01%, respectively. Carryover effect was less than 1%. The linearity was good in the range of urinary iodine values between 60 and 500 μg/L (R2 = 0.99). Good agreement of urinary iodine values was found between manual technique and Seal AA3 HR, using Passing-Bablok regression (y = 7.84 (- 3.00 to 15.29) + 0.95 (0.90 to 1.00) x) and Blant-Altman test. Cusum test for linearity indicates that there is no significant deviation from linearity (P > 0.1). Conclusions: The obtained results proved excellent precision, reproducibility and linearity, comparable to the already used, manual method. The New Seal AA3 HR automatic analyser is acceptable for urinary iodine measurement with very good analytical characteristics and can be used for urinary iodine epidemiological studies of the Croatian population.

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“…Moreover, the different tests used to account for maternal urinary iodine, either through UIC and/or ICr should be acknowledged, with both having strengths and limitations which may have impacted the outcome observed. Urinary iodine as UIC is an easily obtainable indicator of iodine intakes amongst a population and given that the majority of iodine absorbed in the body is excreted in the urine, it is reflective of recent intake [ 29 ]. Although UIC is the most common indicator to assess population iodine intakes there are weaknesses of using UIC independently; notably that there is a high day-to-day variability of iodine intake and this measurement only reflects recent and not long-term intake [ 29 ].…”

Section: Discussionmentioning

confidence: 99%

“…Urinary iodine as UIC is an easily obtainable indicator of iodine intakes amongst a population and given that the majority of iodine absorbed in the body is excreted in the urine, it is reflective of recent intake [ 29 ]. Although UIC is the most common indicator to assess population iodine intakes there are weaknesses of using UIC independently; notably that there is a high day-to-day variability of iodine intake and this measurement only reflects recent and not long-term intake [ 29 ]. Additionally, UIC does not consider thyroid function which could potentially impact urinary iodine and overall iodine status [ 29 ].…”

Section: Discussionmentioning

confidence: 99%

Associations between maternal urinary iodine assessment, dietary iodine intakes and neurodevelopmental outcomes in the child: a systematic review

et al. 2021

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Objective Mild to moderate iodine deficiency during pregnancy has been associated with adverse neurodevelopmental outcomes in offspring. Few research studies to date combine assessment of urinary iodine (UIC and/or ICr), biomarkers that best reflect dietary intake, with reported dietary intake of iodine rich foods in their assessment of iodine deficiency. Thus, a systematic review was conducted to incorporate both these important measures. Design Using PRISMA guidelines, a comprehensive search was conducted in three electronic databases (EMBASE®, MedLine® and Web of Science®) from January 1970–March 2021. Quality assessment was undertaken using the Newcastle Ottawa Scale. Eligible studies included reported assessment of iodine status through urinary iodine (UIC and/or ICr) and/or dietary intake measures in pregnancy alongside neurodevelopmental outcomes measured in the children. Data extracted included study author, design, sample size, country, gestational age, child age at testing, cognitive tests, urinary iodine assessment (UIC in μg/L and/or ICr in μg/g), dietary iodine intake assessment and results of associations for the assessed cognitive outcomes. Results Twelve studies were included with nine reporting women as mild-moderately iodine deficient based on World Health Organization (WHO) cut-offs for urinary iodine measurements < 150 μg/l, as the median UIC value in pregnant women. Only four of the nine studies reported a negative association with child cognitive outcomes based on deficient urinary iodine measurements. Five studies reported urinary iodine measurements and dietary intakes with four of these studies reporting a negative association of lower urinary iodine measurements and dietary iodine intakes with adverse offspring neurodevelopment. Milk was identified as the main dietary source of iodine in these studies. Conclusion The majority of studies classified pregnant women to be mild-moderately iodine deficient based on urinary iodine assessment (UIC and/or ICr) and/or dietary intakes, with subsequent offspring neurodevelopment implications identified. Although a considerable number of studies did not report an adverse association with neurodevelopmental outcomes, these findings are still supportive of ensuring adequate dietary iodine intakes and urinary iodine monitoring throughout pregnancy due to the important role iodine plays within foetal neurodevelopment. This review suggests that dietary intake data may indicate a stronger association with cognitive outcomes than urinary iodine measurements alone. The strength of this review distinguishes results based on cognitive outcome per urinary iodine assessment strategy (UIC and/or ICr) with dietary data. Future work is needed respecting the usefulness of urinary iodine assessment (UIC and/or ICr) as an indicator of deficiency whilst also taking account of dietary intakes.

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The assessment of iodine status – populations, individuals and limitations

Cited by 34 publications

References 60 publications

Intra-individual and inter-individual variations in iodine intake and excretion in adult women: implications for sampling

Intra-individual and inter-individual variations in iodine intake and excretion in adult women: implications for sampling

Analytical evaluation of the new Seal Autoanalyzer 3 High Resolution for urinary iodine determination

Associations between maternal urinary iodine assessment, dietary iodine intakes and neurodevelopmental outcomes in the child: a systematic review

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