Restricted intraindividual urinary iodine concentration variability in nonfasting subjects

Busnardo, B; Nacamulli, Davide; Zambonin, Laura; Mian, Caterina; Piccolo, M.; Girelli, Maria Elisa

doi:10.1038/sj.ejcn.1602334

Cited by 34 publications

(25 citation statements)

References 17 publications

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“…This probably reflects a higher intake of sodium associated with food, in men, because their mean BMI, weight and height, besides sodium urinary excretion, were higher than in women. In other studies, mean UI excretion was also higher in men [8,9,21] , or similar in both genders, being not significant, but higher, in women in the work of Busnardo et al [12] and associated with body weight in the study of Vanacor et al [10] . As body weight is closely associated with gender, it is difficult to separate the impact of each of them in the excretion of UI.…”

Section: Discussionmentioning

confidence: 88%

“…The variability of UI excretion in the same individual has been estimated, in the majority of studies, from spot urine samples, disregarding the variability of UI excretion during a day [7,8,[11][12][13][14] . As food ingested over the weekend can be different from the one ingested on the other days, the objective of this study was to evaluate the variability of 24-hour UI excretion intra-and interindividually on 3 days of a week, including Sunday, in healthy subjects, living in Southern Brazil, and the correlation among the urinary excretion of iodine and sodium.…”

mentioning

confidence: 99%

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Intra- and Interindividual Iodine Excretion in 24 Hours in Individuals in Southern Brazil: A Cross-Sectional Study

Milhoransa¹,

Vanacor²,

Furlanetto³

2010

Ann Nutr Metab

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Aims: To evaluate the variability of 24-hour urinary iodine (UI) excretion intra- and interindividually on three days of a week in healthy subjects, living in southern Brazil, and the correlation among the urinary excretion of iodine and sodium. Methods: Cross-sectional study, including 47 volunteers: 18 individuals with one, 15 individuals with two and 14 individuals with three 24-hour urine samples. Iodine, creatinine and Na⁺ excretion in urine during 24-hour were measured. Results: Mean height, weight, BMI and 24-hour urinary excretion of creatinine were higher in men. UI and urinary sodium were correlated (n = 89, r = 0.524, p = 0.000). UI excretion varied widely, both inter- and intraindividually, on the 3 days of the week, but the mean excretion of UI was similar. In single individuals, the ratio between the maximum and minimum 24-hour UI excretion (m/m) ranged from 1.03 to 2.87, and the median coefficient of variation (CV) was 21% (P₂₅ = 7.0% and P₇₅ = 36.8%), with a range of 1%-51%. 24-hour UI excretion varied greatly among individuals on Sunday (CV = 47.5% and m/m = 7.75), Monday (CV = 38.7% and m/m = 4.60) and Thursday (CV = 40.4% and m/m = 4.50). UI was adequate in the group of 14 people, however, the UI excretion of two women suggested iodine intake persistently below that recommended by WHO. Conclusion: The variability of 24-hour UI excretion on different days in the same individual is lower than that observed among individuals.

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Section: Discussionmentioning

confidence: 88%

mentioning

confidence: 99%

Intra- and Interindividual Iodine Excretion in 24 Hours in Individuals in Southern Brazil: A Cross-Sectional Study

Milhoransa¹,

Vanacor²,

Furlanetto³

2010

Ann Nutr Metab

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“…In contrast to some studies [4,7,9], but in agreement with others [1,19], we defined UI by ICR. A couple of studies [8,28] advised against the use of ICR since it may underestimate UI concentrations compared to 24-hour urine and overestimate iodine concentrations in women compared to men.…”

Section: Discussionmentioning

confidence: 41%

“…Rasmussen et al [1] suggested avoiding non-fasting samples in the morning since UI excretion concentrations seemed to be lowest then. In contrast, Busnardo et al [9] reported only small variations in UI excretion concentrations in non-fasting subjects. Taking the time of sampling into account, the main results of our analyses did not substantially change.…”

Section: Discussionmentioning

confidence: 95%

“…Some sources of nutrition, such as sea fish [3] and milk [4,5], include a large amount of iodine. So far, few studies have investigated intra-individual variations in UI excretion [1,2,6,7,8,9], with the result that a single non-fasting spot urine sample gives only rough information on a subject’s iodine status, with even several samples being insufficient. All of these studies [1,2,6,7,8,9] were conducted with less than 200 participants and focused on day-to-day variations in iodine concentrations.…”

Section: Introductionmentioning

confidence: 99%

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High (but Not Low) Urinary Iodine Excretion Is Predicted by Iodine Excretion Levels from Five Years Ago

Ittermann¹,

Nautsch²,

Schmidt³

et al. 2011

Ann Nutr Metab

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Background: It has not been investigated whether there are associations between urinary iodine (UI) excretion measurements some years apart, nor whether such an association remains after adjustment for nutritional habits. The aim of the present study was to investigate the relation between iodine-creatinine ratio (ICR) at two measuring points 5 years apart. Methods: Data from 2,659 individuals from the Study of Health in Pomerania were analyzed. Analysis of covariance and Poisson regressions were used to associate baseline with follow-up ICR. Results: Baseline ICR was associated with follow-up ICR. Particularly, baseline ICR >300 µg/g was related to an ICR >300 µg/g at follow-up (relative risk, RR: 2.20; p < 0.001). The association was stronger in males (RR: 2.64; p < 0.001) than in females (RR: 1.64; p = 0.007). In contrast, baseline ICR <100 µg/g was only associated with an ICR <100 µg/g at follow-up in males when considering unadjusted ICR. Conclusions: We detected only a weak correlation with respect to low ICR. Studies assessing iodine status in a population should take into account that an individual with a low UI excretion in one measurement is not necessarily permanently iodine deficient. On the other hand, current high ICR could have been predicted by high ICR 5 years ago.

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The Relationship of Central Foveal Thickness to Urinary Iodine Concentration in Retinitis Pigmentosa With or Without Cystoid Macular Edema

et al. 2014

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IMPORTANCE Current treatments for cystoid macular edema (CME) in retinitis pigmentosa (RP) are not always effective, may lead to adverse effects, and may not restore visual acuity. The present research lays the rationale for evaluating whether an iodine supplement could reduce CME in RP.OBJECTIVE To determine whether central foveal thickness (CFT) in the presence of CME is related to dietary iodine intake inferred from urinary iodine concentration (UIC) in nonsmoking adults with RP. DESIGN, SETTING, AND PARTICIPANTSWe performed a cross-sectional observational study of 212 nonsmoking patients aged 18 to 69 years referred to our institution for RP with visual acuity of no worse than 20/200 in at least 1 eye. EXPOSURE Retinitis pigmentosa with or without CME. MAIN OUTCOMES AND MEASURESWith the eye as the unit of analysis, the relationship of log CFT measured by optical coherence tomography to UIC measured from multiple spot samples and represented as a 3-level classification variable (<100, 100-199, and Ն200 μg/L), assigning greater weight to patients with more reliable UIC estimates. RESULTSAnalyses were limited to 199 patients after excluding 11 who failed to return urine samples for measuring UIC and 2 outliers for UIC. Of the 199 patients, 36.2% had CME in 1 or both eyes. Although log CFT was inversely related to UIC based on findings from all eyes (P = .02), regression of log CFT on UIC separately for eyes with and without CME showed a strong inverse significant relationship for the former group (P < .001) and no significant relationship for the latter group (P = .66) as tested. For the eyes with CME, CFT ranged from a geometric mean of 267 μm for a median UIC of less than 100 μg/L to a geometric mean of 172 μm for a median UIC of 200 μg/L or greater. In contrast, we found no significant association between CME prevalence and UIC based on the entire sample as tested (odds ratio, 1.01 [95% CI, 0.38-2.67]; P = .99).CONCLUSIONS AND RELEVANCE A higher UIC in nonsmoking adults with RP was significantly associated with less central foveal swelling in eyes with CME. Additional study is required to determine whether an iodine supplement can limit or reduce the extent of CME in patients with RP.

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Restricted intraindividual urinary iodine concentration variability in nonfasting subjects

Cited by 34 publications

References 17 publications

Intra- and Interindividual Iodine Excretion in 24 Hours in Individuals in Southern Brazil: A Cross-Sectional Study

Intra- and Interindividual Iodine Excretion in 24 Hours in Individuals in Southern Brazil: A Cross-Sectional Study

High (but Not Low) Urinary Iodine Excretion Is Predicted by Iodine Excretion Levels from Five Years Ago

The Relationship of Central Foveal Thickness to Urinary Iodine Concentration in Retinitis Pigmentosa With or Without Cystoid Macular Edema

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