Misclassification of iodine intake level from morning spot urine samples with high iodine excretion among Inuit and non-Inuit in Greenland

Iodine nutrition is commonly assessed from iodine excretion in urine. A 24 h urine sample is ideal, but it is cumbersome and inconvenient. Hence, spot urine samples with creatinine to adjust for differences in void volume are widely used. Still, the importance of ethnicity and the timing of spot urine samples need to be settled. We, thus, collected 104 early morning spot urine samples and 24 h urine samples from Inuit and non-Inuit living in Greenland. Diet was assessed by a FFQ. Demographic data were collected from the national registry and by questionnaires. Iodine was measured using the Sandell–Kolthoff reaction, creatinine using the Jaffe method and para-amino benzoic acid by the HPLC method for the estimation of completeness of urine sampling and compensation of incomplete urine samples to 24 h excretion. A population-based recruitment was done from the capital city, a major town and a settlement (n 36/48/20). Participants were seventy-eight Inuit and twenty-six non-Inuit. The median 24 h iodine excretion was 138 (25th–75th percentile 89–225) μg/97 (25th–75th percentile 72–124) μg in Inuit/non-Inuit (P= 0·030), and 153 (25th–75th percentile 97–251) μg/102 (25th–75th percentile 73–138) μg (P= 0·026) when including compensated iodine excretion. Iodine excretion in 24 h urine samples increased with a rising intake of traditional Inuit foods (P= 0·005). Iodine excretion was lower in morning spot urine samples than in 24 h urine samples (P< 0·001). This difference was associated with iodine intake levels (P< 0·001), and was statistically significant when the iodine excretion level was above 150 μg/24 h. In conclusion, the iodine intake level was underestimated from morning spot urine samples if iodine excretion was above the recommended level.

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Reliability of studies of iodine intake and recommendations for number of samples in groups and in individuals

British Journal Of Nutrition ◽

10.1017/s0007114507842292 ◽

2007 ◽

Vol 99 (4) ◽

pp. 813-818 ◽

Cited By ~ 151

Author(s):

Stig Andersen ◽

Jesper Karmisholt ◽

Klaus M. Pedersen ◽

Peter Laurberg

Keyword(s):

Standard Deviation ◽

Urinary Iodine ◽

Iodine Intake ◽

Urine Samples ◽

Urinary Iodine Excretion ◽

Iodine Nutrition ◽

Cross Sectional ◽

Spot Urine ◽

Iodine Excretion ◽

And Gender

The iodine intake level in a population is determined in cross-sectional studies. Urinary iodine varies considerably and the reliability of studies of iodine nutrition and the number of samples needed is unsettled. We performed a longitudinal study of sixteen healthy men living in an area of mild to moderate iodine deficiency. Iodine and creatinine concentrations were measured in spot urine samples collected monthly for 13 months. From these data we calculated the number of urine samples needed to determine the iodine excretion level for crude urinary iodine and for 24 h iodine excretion estimated from age- and gender-specific creatinine excretions. We found that mean urinary iodine excretion varied from 30 to 87 μg/l (31 to 91 μg/24 h). Sample iodine varied from 10 to 260 μg/l (20 to 161 μg/24 h). Crude urinary iodine varied more than estimated 24 h iodine excretion (population standard deviation 32v. 26; individual standard deviation 29v. 21; Bartlett's test,P < 0·01 for both). The number of spot urine samples needed to estimate the iodine level in a population with 95 % confidence within a precision range of ± 10 % was about 125 (100 when using estimated 24 h iodine excretions), and within a precision range of ± 5 % was about 500 (400). A precision range of ± 20 % in an individual required twelve urine samples or more (seven when using estimated 24 h iodine excretions). In conclusion, estimating population iodine excretion requires 100–500 spot urine samples for each group or subgroup. Less than ten urine samples in an individual may be misleading.

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Nationwide Representative Survey of Dietary Iodine Intake and Urinary Excretion in Postpartum Korean Women

Nutrients ◽

10.3390/nu13113955 ◽

2021 ◽

Vol 13 (11) ◽

pp. 3955

Author(s):

Do-Kyung Lee ◽

Hunjoo Lee ◽

Hyeyoung Lee ◽

Taehyung Yoon ◽

Seon-Joo Park ◽

...

Keyword(s):

Large Scale ◽

Urinary Iodine ◽

Brown Seaweed ◽

Nationwide Survey ◽

Iodine Intake ◽

Urinary Iodine Excretion ◽

Korean Women ◽

Spot Urine ◽

Before And After ◽

Iodine Excretion

Iodine is an essential component of thyroid hormones, but excessive iodine intake can lead to thyroid dysfunction. Traditionally, Korean mothers consume brown seaweed soup (miyeokguk), a high source of iodine, after childbirth. There is controversy regarding the effects of excessive postpartum iodine intake on the health of mothers and infants. Thus far, there have been no nationwide large-scale surveys regarding the status of iodine intake among postpartum women in Korea. Therefore, we conducted a nationwide survey of postpartum dietary iodine intake among Korean women. In total, 1054 Korean women aged ≥19 years, at less than 8 weeks postpartum, participated in this survey. Dietary data were collected using self-reported 2-day dietary records, along with before-and-after meal photos. To evaluate the correlation between dietary iodine and urinary iodine excretion (UIE), spot urine, and 24 h urine samples were collected from 98 and 29 participants, respectively. The mean daily iodine intake among all participants was 2945.6 μg, and it gradually decreased over time after childbirth. Dietary iodine intake was significantly correlated with 24 h UIE (r = 0.396, p < 0.05) and spot urine UIE (r = 0.312, p < 0.05). Follow-up studies are required to examine the influence of excessive postpartum iodine intake on thyroid health in mothers and their infants.

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Urinary iodine excretion in Belarus children

Acta Endocrinologica ◽

10.1530/eje.0.1330216 ◽

1995 ◽

Vol 133 (2) ◽

pp. 216-217 ◽

Cited By ~ 10

Author(s):

TA Mityukova ◽

LN Astakhova ◽

LD Asenchyk ◽

MM Orlov ◽

L VanMiddlesworth

Keyword(s):

Thyroid Cancer ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Iodine Intake ◽

Urine Samples ◽

Urinary Iodine Excretion ◽

University Of Tennessee ◽

Iodine Excretion

Mityukova TA, Astakhova LN, Asenchyk LD, Orlov MM, VanMiddlesworth L. Urinary iodine excretion in Belarus children. Eur J Endocrinol 1995;133:216–7. ISSN 0804–4643. Casual urine samples were collected to determine iodine excretion of 1680 Belarus children during 1990–1994. The subjects, 8–16 years old, were from nine different regions of Belarus; 60% were from the Gomel oblast, which has been associated with relatively high levels of radioiodine fallout and increased incidence of thyroid cancer. Most of the median values indicate borderline/low iodine intake or mild iodine deficiency. Ranges were wide but 163 children excreted < 20 μgI/l urine and they should be considered severely deficient in iodine. L VanMiddlesworth, Dept. of Physiology and Biophysics, University of Tennessee, 894 Union Avenue, Memphis, TN 38163, USA

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Urinary iodine excretion in urine samples among children in Dang district, Gujarat

International Journal of Community Medicine and Public Health ◽

10.18203/2394-6040.ijcmph20172820 ◽

2017 ◽

Vol 4 (7) ◽

pp. 2339

Author(s):

Rahul Damor ◽

Jatin Chhaya ◽

Sukesha Gamit ◽

Jayant Patel ◽

J. K. Kosambiya

Keyword(s):

Iodine Deficiency ◽

Primary Schools ◽

Urinary Iodine ◽

Human Growth ◽

Iodine Intake ◽

Urine Samples ◽

Urinary Iodine Excretion ◽

Urinary Iodine Concentration ◽

Cross Sectional ◽

Iodine Excretion

Background: Iodine is an essential micronutrient required for normal human growth and development as it is needed for the synthesis of thyroid hormones produced by thyroid glands. The sicknesses occurred due to deficiencies of iodine in the nutrition are termed iodine deficiency disorders. Urinary iodine concentration is the prime indicator of a person’s nutritional iodine status. So, the aim of this study was to assess the status of iodine deficiency based on median urinary iodine excretion.Methods: Community based cross sectional study was carried out among purposively selected primary schools of the Dang district. All students between the age group of 6 to 12 years who were present on the day of visit were included in the study. A total 387 urine samples were collected during the period of August 2015 to September 2016.Results: Based on median urinary iodine excretion, among total analysed samples, about 6.5% samples confirmed severe iodine deficiency, 22% samples showed moderate iodine deficiency and about 36% samples indicated mild iodine deficiency. About one third (31.3%) samples suggested optimum iodine intake. Only few samples (4.4%) revealed more than required iodine intake.Conclusions: About one third (31.3%) of the surveyed population had adequate iodine intake while majority (64.4%) of them had inadequate iodine intake.

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

British Journal Of Nutrition ◽

10.1017/s0007114519003015 ◽

2019 ◽

Vol 123 (9) ◽

pp. 987-993 ◽

Cited By ~ 1

Author(s):

Wen Chen ◽

Shu Gao ◽

Wenxing Guo ◽

Long Tan ◽

Ziyun Pan ◽

...

Keyword(s):

Urinary Iodine ◽

Sampling Period ◽

Iodine Concentration ◽

Iodine Intake ◽

Urine Samples ◽

Urinary Iodine Excretion ◽

Urinary Iodine Concentration ◽

Adult Women ◽

Individual Variations ◽

Iodine Excretion

AbstractIodine 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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Persistent Microalbuminuria in Human Immunodeficiency Virus Infected Children in Kano, Nigeria

International Journal of Nephrology ◽

10.1155/2014/567838 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Abdullahi Mudi ◽

Bashir U. Alhaj ◽

Fatimah Hassan-Hanga ◽

Isah Adagiri Yahaya

Keyword(s):

Highly Active Antiretroviral Therapy ◽

Early Morning ◽

Urine Samples ◽

Female Ratio ◽

Albumin Creatinine Ratio ◽

Spot Urine ◽

Highly Active ◽

Immunodeficiency Virus ◽

Duration Of Infection ◽

Male To Female

Microalbuminuria has been reported to be a precursor of HIV related renal disease, which if detected early and coupled with appropriate intervention may slow or retard the progress of the disease. One hundred and seventy-eight HIV infected children aged 15 years and below were recruited from the Paediatric Infectious Disease Clinic of Aminu Kano Teaching Hospital (AKTH), Kano, to determine the prevalence of persistent microalbuminuria using the albumin creatinine ratio (ACR). Early morning urine samples and spot urine samples were analyzed using a dipstick specific for microalbumin. Those who tested positive had their samples reanalyzed in the laboratory using immunometric assay and Jaffe reaction method for albumin and creatinine, respectively. Patients that had ACR of 30–300 mg/g were said to have microalbuminuria and had their urine samples retested after 6 to 8 weeks. Twelve children (6.7%) had persistent microalbuminuria and had a mean age of7.5±3.3years, with a male to female ratio of 1 : 1. There was no significant relationship between the finding of microalbuminuria and age, sex, duration of infection, and the use of highly active antiretroviral therapy. Periodic screening for microalbuminuria using albumin specific dipstick should be considered for children with HIV infection.

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Dietary ratio of animal:plant protein is associated with 24-h urinary iodine excretion in healthy school children

British Journal Of Nutrition ◽

10.1017/s0007114515001567 ◽

2015 ◽

Vol 114 (1) ◽

pp. 24-33 ◽

Cited By ~ 7

Author(s):

Gabriela Montenegro-Bethancourt ◽

Simone A. Johner ◽

Peter Stehle ◽

Thomas Remer

Keyword(s):

Repeated Measures ◽

Salt Intake ◽

Urinary Iodine ◽

Iodine Intake ◽

Urinary Iodine Excretion ◽

Dietary Intakes ◽

Iodine Nutrition ◽

Protein Ratio ◽

Iodine Excretion ◽

Small Decline

Adequate dietary iodine intake in children is essential for optimal physical and neurological development. Whether lower dietary animal food and salt intake may adversely affect iodine status is under discussion. We examined the association between dietary animal:plant protein ratio with 24-h urinary iodine excretion (24-h UI, μg/d), and whether this is modified by salt intake. A 24-h UI was measured in 1959 24-h urine samples from 516 6- to 12-year-old participants of the Dortmund Nutritional and Anthropometric Longitudinally Designed Study. Parallel 3 d weighed food records were used to estimate dietary intakes. Protein sources were classified as dairy, animal and plant. A repeated-measures regression model (PROC MIXED) was used to analyse the effect of animal:plant protein ratios on 24-h UI. Animal:plant protein ratios ranged from 0·5 (95 % CI 0·4, 0·6) to 1·6 (95 % CI 1·4, 1·9) (lowest and highest quartile). After adjustment for total energy intake, main dietary iodine sources (dairy and salt intake), and further covariates, the inter-individual variation in animal:plant protein ratio was significantly associated with variation in 24-h UI. One unit higher animal:plant protein ratio predicted 6 μg/d higher 24-h UI (P= 0·002) in boys and 5 μg/d (P= 0·03) in girls. This relationship was partially mediated by a higher salt intake at higher animal:plant protein ratios. These results suggest that lower consumption of animal protein is associated with a small decline in iodine excretion, partially mediated by decreased salt intake. Because limited salt and increased intake of plant-based foods are part of a preferable healthy food pattern, effective nutrition political strategies will be required in the future to ensure appropriate iodine nutrition in adherent populations.

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Thyroid structure and size and two-year follow-up of solitary cold thyroid nodules in an unselected population with borderline iodine deficiency

Acta Endocrinologica ◽

10.1530/eje.0.1420224 ◽

2000 ◽

pp. 224-230 ◽

Cited By ~ 56

Author(s):

N Knudsen ◽

H Perrild ◽

E Christiansen ◽

S Rasmussen ◽

H Dige-Petersen ◽

...

Keyword(s):

Iodine Deficiency ◽

Thyroid Nodules ◽

Thyroid Volume ◽

Iodine Concentration ◽

Iodine Intake ◽

Spot Urine ◽

High Prevalence ◽

Iodine Excretion ◽

Cold Thyroid Nodules

OBJECTIVE: Multinodular goitre has been found with a high prevalence in iodine-deficient areas, but less frequently in iodine-replete areas; the iodine intake sufficient to prevent goitre has not been established, however. METHODS: We report data from an ultrasonic investigation of the thyroid glands of 2656 randomly selected subjects aged 41 to 71 years in an area with borderline iodine deficiency. RESULTS: Median iodine concentration in spot urine samples was 70microg/l. Multinodular thyroid structure was found in 23% of the population, increasing in women from 20 to 46% with increasing age, and in men from 7 to 23%. Solitary, scintigraphically cold, thyroid nodules >10mm were found in 2.4% of the population with the same prevalence in the different age and sex groups. Two years of follow-up of these cold nodules revealed no signs of malignancies. Median thyroid volume was 11.0ml. Thyroid enlargement (>18ml for women and >25ml for men) was found among 13. 1% of the women and 6.2% of the men, and the prevalence increased with age. The presence of thyroid nodules was related to positive anti-thyroperoxidase antibody (TPO Ab) titres, whereas thyroid enlargement was associated with iodine excretion <50microg/day. CONCLUSIONS: Thyroid enlargement was associated with low iodine excretion and median thyroid volume was slightly increased compared with iodine-replete areas. Multinodular thyroid structure was found with a high prevalence and was associated with TPO Ab >200kU/l. Cold thyroid nodules were moderately prevalent, with no cases of detected malignancies during 2 years of follow-up.

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Long-term iodine nutrition is associated with longevity in older adults: a 20 years’ follow-up of the Randers–Skagen study

British Journal Of Nutrition ◽

10.1017/s0007114520001592 ◽

2020 ◽

pp. 1-6

Author(s):

Johannes Riis ◽

Klaus M. Pedersen ◽

Mathias B. Danielsen ◽

Gustav V. B. Sørensen ◽

Martin G. Jørgensen ◽

...

Keyword(s):

Cox Regression ◽

Urinary Iodine ◽

Iodine Content ◽

Iodine Intake ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

Spot Urine ◽

Co Morbidity

Abstract Iodine intake affects the occurrence of thyroid disorders. However, the association of iodine intake with longevity remains to be described. This led us to perform a 20 years’ follow-up on participants from the Randers–Skagen (RaSk) study. Residents in Randers born in 1920 (n 210) and Skagen born in 1918–1923 (n 218) were included in a clinical study in 1997–1998. Mean iodine content in drinking water was 2 µg/l in Randers and 139 µg/l in Skagen. We collected baseline data through questionnaires, performed physical examinations and measured iodine concentrations in spot urine samples. Income data were retrieved from Danish registries. We performed follow-up on mortality until 31 December 2017 using Danish registries. Complete follow-up data were available on 428 out of 430 of participants (99·5 %). At baseline, the median urinary iodine concentration was 55 µg/l in Randers and 160 µg/l in Skagen residents. Participants were long-term residents with 72·8 and 92·7 % residing for more than 25 years in Randers and Skagen, respectively. Cox regression showed that living in Skagen compared with Randers was associated with a lower hazard ratio (HR) of death in both age- and sex-adjusted analyses (HR 0·60, 95 % CI 0·41, 0·87, P = 0·006), but also after adjustment for age, sex, number of drugs, Charlson co-morbidity index, smoking, alcohol and income (HR 0·60, 95 % CI 0·41, 0·87, P = 0·008). Residing in iodine-replete Skagen was associated with increased longevity. This indicates that long-term residency in an iodine-replete environment may be associated with increased longevity compared with residency in an iodine-deficient environment.

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Evaluation of calcium to phosphorus ratio in spot urine samples as a practical method to monitor phosphorus intake adequacy in sows

Journal of Animal Science ◽

10.1093/jas/skab335 ◽

2021 ◽

Author(s):

Mariola Grez-Capdeville ◽

Thomas D Crenshaw

Keyword(s):

Physiological State ◽

Roc Curves ◽

Strong Relationship ◽

Weighted Kappa ◽

Practical Method ◽

Early Morning ◽

Late Gestation ◽

Urine Samples ◽

Spot Urine ◽

Phosphorus Intake

Abstract The objective of this study was to evaluate the reliability of using Ca to P ratio measured in spot urine samples to assess P intake adequacy in gestating and lactating sows. A total of 36 sows were fed one of six concentrations of dietary total P (0.40, 0.48, 0.56, 0.64, 0.72, 0.80%) from day 7.5 + 1 after breeding until the end of lactation (day 26.6 + 1). Dietary Ca to P ratio was maintained constant across treatments at 1.25. Total 24-hour urine samples were collected in mid and late gestation (days 77.1 + 2 and 112.4 + 1), and early and late lactation (days 4.5 + 1 and 18.2 + 1). In parallel to 24-hour collections, spot urine samples were collected at three different times (early morning, late morning, and late afternoon) in late gestation and late lactation. Urine Ca and P concentrations were measured and Ca to P ratio was calculated. Sows were classified as P-adequate or P-deficient according to dietary P intake. Urine Ca to P ratio was greater in sows fed P-deficient diets than sows fed P-adequate diets (P < 0.001). Receiver operator characteristic (ROC) curves were used to determine the cut-off values for urine Ca to P ratio to predict P intake adequacy. Three different categories of P intake were defined according to urine Ca to P ratio: deficient, adequate, and excessive. The area under the ROC for Ca to P ratio was 0.88 (95% CI 0.81 – 0.95). Best cut-off value of urine Ca to P ratio was 1.5 (sensitivity 94% and specificity 68%) to identify sows fed P-deficient diets and 0.5 for P-excessive diets (sensitivity 82% and specificity 82%). A strong relationship between Ca to P ratio in 24-hour and spot urine samples was determined (r = 0.93, P < 0.01), independent of physiological state and collection time of spot samples (adjusted-R 2 = 0.86, P < 0.01). The degree of agreement between spot and 24-hour urine for P intake adequacy, assessed by Cohen’s weighted kappa analysis, was substantial (0.78, 95% CI 0.69 – 0.88). We conclude that urinary Ca to P ratio provides a reliable prediction of the adequacy of P intake in reproducing sows. Urinary Ca to P ratio measurements in random spot urinary offers a practical method to determine dietary P adequacy.

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