Casual Urine Samples Research Articles

Sodium intake in Germany.

For many years, a high sodium intake has been discussed as a potential risk factor in the development of hypertension and, consequently, cardiovascular diseases. As part of the German Health Interview and Examination Survey for Adults (DEGS1), which was conducted between 2008 and 2011, sodium excretion in casual urine samples was used as a biomarker to measure sodium intake. DEGS1 observed that the median daily sodium intake of women (3.4 g) as well as men (4.0 g) exceeds the levels recommended by German and international organisations. Among other factors, men's higher sodium intake could be explained by their higher energy intake. In addition, DEGS1 demonstrates an association between women's sodium intake and age; however, no equivalent correlation was identified for men. Furthermore, although high socio-economic status is associated with lower sodium intake in men, no comparable correlation was observed among women.

PP.30.07] DIURNAL PATTERN OF URINARY SODIUM/POTASSIUM RATIO IN FREE LIVING JAPANESE IN DIVIDUALS

Objective: High dietary sodium (Na), low dietary potassium (K) intakes and high Na/K ratio are associated with adverse blood pressure levels and excess risks of cardiovascular diseases. Handy urinary Na/K ratio measurement device provides feedback in several ten seconds with far lower patient burden as compared to conventional methods. Since there is no report on diurnal variation of casual urinary Na/K ratio, we clarified it under free living conditions in Japanese participants.Design and method: This study is a cross sectional study. A total of 122 normotensve and hypertensive individuals (ages 25–69 years) were recruited. Participants were instructed to collect all casual urine samples in aliquot tubes (10 mL), and to report urine volume and the time at each voiding under free living conditions for 10 to 22 days. Urinary sodium and potassium concentration was measured by ion-specific electrodes, and Na/K ratio was calculated. 13,277 specimens were collected and classified into hourly data from 00:00 hours to 23:00 hours on the hour. Diurnal pattern of urinary Na/K ratio, urinary concentrations and excretions of sodium and potassium, and urine volume were evaluated. Results: Mean value of 24-hr urinary Na/K ratio were 4.37 and 3.43 in normotensive and hypertensive individuals, respectively. Of the individuals on anti-hypertensive medications, 14 participants, 9 participants, 15 participants and 5 participants were taking calcium channel blockers (CCB), angiotensin 2 receptor blockers (ARB), both CCB and ARB, and other drugs, respectively. Overall mean value of urinary Na/K ratio was highest (4.1–5.0) in the early morning, lower (3.3–3.8) in daytime and higher (4.0–4.4) toward evening hours. Mean urinary sodium and potassium concentration was lowest (90–110mmol/L, 24–32mmol/L, respectively) in the early morning, and higher (110–140mmol/L, 35–43mmol/L, respectively) after second voiding. Diurnal variability ratio of potassium concentration was larger than sodium concentration. In subgroup analysis, diurnal patterns of mean urinary Na/K ratio were comparable between normotensive and hypertensive individuals. Conclusions: We identified a diurnal pattern in urinary Na/K ratio under free living conditions. This fluctuation of urinary Na/K ratio was 1 to 1.5, and its variation is not likely to be explained by postprandial surges.

Evaluation of Equations for Predicting 24-Hour Urinary Sodium Excretion from Casual Urine Samples in Asian Adults

Background: The collection of 24-h urine samples for the estimation of sodium intake is burdensome, and the utility of spot urine samples in Southeast Asian populations is unclear.Objective: We aimed to assess the validity of prediction equations with the use of spot urine concentrations.Methods: A sample of 144 Singapore residents of Chinese, Malay, and Indian ethnicity aged 18–79 y were recruited from the Singapore Health 2 Study conducted in 2014. Participants collected urine for 24 h in multiple small bottles on a single day. To determine the optimal collection time for a spot urine sample, a 1-mL sample was taken from a random bottle collected in the morning, afternoon, and evening. Published equations and a newly derived equation were used to predict 24-h sodium excretion from spot urine samples.Results: The mean ± SD concentration of sodium from the 24-h urine sample was 125 ± 53.4 mmol/d, which is equivalent to 7.2 ± 3.1 g salt. Bland-Altman plots showed good agreement at the group level between estimated and actual 24-h sodium excretion, with biases for the morning period of –3.5 mmol (95% CI: –14.8, 7.8 mmol; new equation) and 1.46 mmol (95% CI: –10.0, 13.0 mmol; Intersalt equation). A larger bias of 25.7 mmol (95% CI: 12.2, 39.3 mmol) was observed for the Tanaka equation in the morning period. The prediction accuracy did not differ significantly for spot urine samples collected at different times of the day or at a random time of day (P = 0.11–0.76).Conclusion: This study suggests that the application of both our own newly derived equation and the Intersalt equation to spot urine concentrations may be useful in predicting group means for 24-h sodium excretion in urban Asian populations.

Iodine nutrition status in clinically euthyroid pregnant women attending in BSMMU

Background: Iodine deficiency disorders (IDD) are common nutritional problem globally. All groups of people are affected by it, but the pregnant women and their neonates are most vulnerable.Objectives: This study was carried out to see the iodine status of pregnant women using median urinary iodine concentration (MUI) as a measure of outcome. Methods: This cross sectional observational study assessed the MUI in casual urine samples from 225 pregnant women (75 pregnants from each trimester) and 75 non-pregnant healthy controls. The urinary iodine content was estimated in urine sample using the method of Dunn et al. with the modification of Sandell & Kolthoff (wet digestion method).Results: Median value of urinary iodine in pregnant women was 48.21Ug/L compared to 52.27

Iodine Supplementation of Mildly Iodine-Deficient Adults Lowers Thyroglobulin: A Randomized Controlled Trial.

An inverse relationship between thyroglobulin (Tg) and urinary iodine concentration (UIC) has been found in children, potentially making Tg a viable blood marker of iodine status. The application of Tg in adults is unknown. The objective of the study was to determine the efficacy of Tg to assess iodine status in adults. This was a randomized, double-blind, placebo-controlled, clinical trial. The study was conducted in Dunedin, New Zealand. Mildly iodine deficient adults (n = 112) aged 18–40 years participated in the study. Participants were supplemented with 150 μg of iodine as potassium iodate or placebo daily for 24 weeks. At baseline and 24 weeks, participants provided five casual urine samples for UIC determination; serum TSH and free T4 (FT4) was also measured. Tg was determined at baseline and 8, 16, and 24 weeks. A change in Tg concentration between the iodine-supplemented and placebo groups at 24 weeks. At baseline, the overall median UIC was 65 μg/L, confirming that participants were mildly iodine deficient (ie, median UIC between 50 and 99 μg/L). The overall median Tg was 16.6 μg/L; TSH and FT4 were within normal reference ranges. At 24 weeks, the median UIC of the placebo and supplemented groups was significantly different, 79 and 168 μg/L, respectively (P < .001). Tg in the iodine-supplemented group decreased by 12%, 20%, and 27% compared with the placebo group at 8 (P = .045), 16 (P < .001), and 24 weeks (P < .001); there were no significant changes in TSH and FT4. Improved iodine status as assessed by UIC was associated with a concomitant decrease in Tg concentration, demonstrating that Tg is a useful biomarker of iodine status in a group of adults.

Four to seven random casual urine specimens are sufficient to estimate 24-h urinary sodium/potassium ratio in individuals with high blood pressure.

This study was done to clarify the optimal number and type of casual urine specimens required to estimate urinary sodium/potassium (Na/K) ratio in individuals with high blood pressure. A total of 74 individuals with high blood pressure, 43 treated and 31 untreated, were recruited from the Japanese general population. Urinary sodium, potassium and Na/K ratio were measured in both casual urine samples and 7-day 24-h urine samples and then analyzed by correlation and Bland–Altman analyses. Mean Na/K ratio from random casual urine samples on four or more days strongly correlated with the Na/K ratio of 7-day 24-h urine (r=0.80–0.87), which was similar to the correlation between 1 and 2-day 24-h urine and 7-day 24-h urine (r=0.75–0.89). The agreement quality for Na/K ratio of seven random casual urine for estimating the Na/K ratio of 7-day 24-h urine was good (bias: −0.26, limits of agreements: −1.53–1.01), and it was similar to that of 2-day 24-h urine for estimating 7-day 24-h values (bias: 0.07, limits of agreement: −1.03 to 1.18). Stratified analyses comparing individuals using antihypertensive medication and individuals not using antihypertensive medication showed similar results. Correlations of the means of casual urine sodium or potassium concentrations with 7-day 24-h sodium or potassium excretions were relatively weaker than those for Na/K ratio. The mean Na/K ratio of 4–7 random casual urine specimens on different days provides a good substitute for 1–2-day 24-h urinary Na/K ratio for individuals with high blood pressure.

Urinary Iodine Excretion among Nepalese School Children in Terai Region.

To assess the current iodine status among school children in Terai region of Nepal. A cross sectional study was conducted in 2012 among the school children aged 6-12y in three Terai districts (Siraha, Saptari and Jhapa) of eastern Nepal. A total of 1105 casual urine samples were collected from children of different schools of above districts. Urinary iodine excretion was estimated using ammonium persulphate digestion method. The median urinary iodine excretion in school children was 226.33μg/L (234.16μg/L, 229.25μg/L and 210.67μg/L in Siraha, Saptari and Jhapa districts respectively). About 12.7% (n = 140) children were found to be iodine deficient and 34.2% (n = 378) children had excessive iodine nutrition. There was good improvement in iodine nutrition among children in Terai region, with a large part of population showing excessive iodine nutrition.

Iodine nutritional status in Himachal Pradesh state, India.

Introduction:Iodine deficiency (ID) is the preventable causes of mental retardation worldwide. Himachal Pradesh (HP) state is a known endemic region to ID.Objective:the objective was to assess the current status of iodine nutrition in a population of HP, India.Methodology:There are three regions in HP namely: Kangra, Mandi, and Shimla. In each region, one district was selected namely: Kangra, Kullu, and Solan. In each district, 30 clusters were identified by utilizing population proportional-to-size cluster sampling methodology. A total of 5748 school-age children (SAC) (Kangra; 1864, Kullu; 1986, Solan: 1898), 1711 pregnant mothers (PMs) (Kangra; 647, Kullu; 551, Solan: 513), and 1934 neonates (Kangra; 613, Kullu; 638, Solan: 683), were included in study. Clinical examination of thyroid of each child and PM was conducted. Casual urine samples were collected from children and PMs. Cord blood samples were collected for estimation of thyroid stimulating hormone (TSH) among neonates.Results:In SAC, total goiter rate (TGR) was 15.8% (Kangra), 23.4% (Kullu), and 15.4% (Solan). Median urinary iodine concentration (UIC) level was 200 μg/l (Kangra), 175 μg/l (Kullu), and 62.5 μg/l (Solan). In PMs, TGR was 42.2% (Kangra), 42.0% (Kullu), and 19.9% (Solan). Median UIC level was 200 μg/l (Kangra), 149 μg/l (Kullu), and 130 μg/l (Solan). In Neonates, TSH levels of > 5 mIU/L were found in 73.4 (Kangra), 79.8 (Kullu), and 63.2 (Solan) percent of neonates.Conclusion:As per, UIC level (<100 μg/l) in SAC, ID was found in district Solan. In Kullu and Solan districts, there were ID (UIC level < 150 μg/l) among PMs. TSH levels indicated ID in all districts surveyed.

The status of iodine nutrition and iodine deficiency disorders among school children in Metekel Zone, northwest Ethiopia.

Iodine deficiency disorders are serious public health problems in Ethiopia. The aim of this study was to measure the prevalence and severity of iodine deficiency disorders among school children in Metekel Zone. A cross-sectional school based descriptive study was conducted between February 2011 and July 2012. One school containing 750 children aged between 6 and 18 years was randomly selected. Two hundred students from this school were selected by systematic random sampling. Physical examination was made according to WHO goiter classification system; 50 salt samples from households to which the sampled children belonged were tested for iodine using rapid field test kits and titration; a casual urine sample (5 ml) was taken from 30 children to measure urinary iodine spectrophotometrically, and 5 ml venous blood sample were collected from 37 children to measure thyroid relevant blood constituents using ELISA. The total goiter prevalence was 39.5%; 60% of the salt samples contained no iodine. The median urinary iodine concentration ranged from 20.54 - 62.2 (39.9 µg/L). School children who were assessed for thyroid hormones showed 18.92% elevated and 27.03% suppressed TSH levels. The study demonstrated that iodine deficiency is still a severe public health problem in Metekel Zone. There is a need to further strengthen the existing controlling and monitoring system in order to achieve proper elimination of IDDs in the community.

Six random specimens of daytime casual urine on different days are sufficient to estimate daily sodium/potassium ratio in comparison to 7-day 24-h urine collections

The objective of this study was to determine the optimal number and type of casual (spot) urine specimens required to estimate an individual's urinary sodium/potassium (Na/K) ratio. A total of 48 participants, 25 men and 23 women, aged between 25 and 59 years, was recruited from healthy volunteers. The Na/K ratio in each casual urine and 7-day 24-h urine sample was measured. Correlation analysis and the quality of agreement by the Bland and Altman method between casual urine and 24-h urine were analyzed. The mean Na/K ratio of 7-day 24-h urine was 4.3. The mean Na/K ratio of six random specimens of daytime (collected between 09 and 17 hours) casual urine correlated most strongly with the Na/K ratio of 7-day 24-h urine (r=0.87). The bias for the mean Na/K ratio between 7-day 24-h urine and daytime casual urine was almost negligible (0.03), and the quality of agreement for the mean of the six random, daytime casual urine specimens on different days was similar to that of the 2-day 24-h urine samples for estimating 7-day 24-h values. Our findings show that the mean Na/K ratio of six random daytime casual urine specimens on different days was a good substitute for the 2-day 24-h urine Na/K ratio.

Elliott et al. Respond to "Quantifying Urine Sodium Excretion"

In their commentary (1) on our article (2), de Boer and Kestenbaum briefly summarized recent research on the relationship between salt intake (estimated from urinary sodium excretion) and cardiovascular disease (CVD). They cite a recent article by O'Donnell et al. (3) in which casual urine samples were used to characterize individual sodium intakes and an apparent J-shaped association was observed between sodium intake and CVD risk. de Boer and Kestenbaum state that “a very low intake of dietary sodium may truly increase the risk of CVD” (1, p. 1193); in contrast, an editorial (4) accompanying the article by O'Donnell et al. and subsequent publications (5–7) have highlighted methodological concerns about interpretation of the study findings. These include the use of a clinical trial population with established CVD or diabetes; high rates of medication usage among trial participants; use of a single casual urine sample to estimate individual sodium intake; inclusion of participants with sodium intakes at the bottom end of the distribution who appeared to be sicker than the rest of the study population (reverse causality); and use of data sets not specifically designed to address the sodium-CVD relationship. de Boer and Kestenbaum also cite studies purporting to show that “[d]ietary sodium restriction can lead to adverse biologic responses, including activation of the renin-angiotensin system, stimulation of the sympathetic nervous system, and unfavorable alterations to serum lipids” (1, p. 1193). These matters have been thoroughly examined as part of a systematic review undertaken by the World Health Organization to reassess guidelines on population sodium intakes (8, 9). The World Health Organization reaffirmed its previous advice that salt intake should be less than 5 g (85 mmol sodium) per day in adults and for the first time recommended a reduction in sodium intake to control blood pressure in children (8). The World Health Organization review found no evidence for adverse effects on physiological response to sodium reduction, including on the sympathetic nervous system or blood lipids (8, 9). We agree with de Boer and Kestenbaum that the International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT) equations “now represent the best available method to estimate urine sodium excretion from casual urine samples” (1, p. 1194), although there are limitations. They suggest that simple transformations may improve model fit. We re-ran the equations using the natural logarithm of the urinary excretion values. This resulted in only modest improvement in model fit; the adjusted R2 increased from 0.2659 (Table 1 of our original article) to 0.2684 in men, and from 0.2327 to 0.2418 in women. We confirm that addition of urine potassium concentrations did not meaningfully improve the models; with exclusion of potassium, the adjusted R2 was reduced to 0.2636 in men and 0.2310 in women. We therefore agree with de Boer and Kestenbaum that urinary potassium can be excluded from the models and provide revised model estimates that exclude potassium in Table 1. We disagree with de Boer and Kestenbaum that inclusion of dummy variables for the 5 regions included in the models may inflate the community-level performance of the equation (1). We think it is important to include such an adjustment; by fitting a different intercept for each region, we reduce the impact of cross-region differences in levels of sodium excretion on the within-region associations of casual to 24-hour sodium excretion. Table 1. Multiple Linear Regression Analyses of Sex-Specific Individual 24-Hour Urinary Sodium Excretion in Test and Validation Data Sets Combined, International Cooperative Study on Salt, Other Factors, and Blood Pressure, 1984–1987 We restricted our analyses to Western populations in INTERSALT for which we had the most data and which are likely to be the most representative of the situation in North America and Europe. We therefore agree that the equations should be used with caution outside of these 2 settings and outside the age range for which the equations were developed (20–59 years). Finally, we agree that single urinary measures of sodium excretion are limited for assessing individual (compared with population-wide) sodium intakes. We also concur that multiple urine collections are preferable and required to increase reliability and reduce the “regression-dilution” problem for studies of individuals (10, 11).

Invited Commentary: Quantifying Salt in Urine--A Complex Solution

Reduction of dietary sodium intake has been identified as a priority to reduce the worldwide burden of hypertension and cardiovascular disease. Dietary sodium intake is most precisely ascertained by using timed urine collection. Casual urine sodium measurements are relatively easy to perform, but their relationship to timed urine sodium measurements is unclear. In this issue of the Journal, Brown et al. (Am J Epidemiol. 2013;177(11):1180-1192) report the development and validation of equations to estimate 24-hour urine sodium excretion from casual urine samples. Their study included a large number of participants on 2 continents, a well-collected gold standard, separate discovery and validation samples, and relevant covariates. The resulting equations represent the best available methods to estimate dietary sodium intake from casual urine samples. However, the study is limited by evidence of a suboptimal model fit, restriction to people 20-59 years of age in North America and Europe, and exclusion and adjustment that further limit external validity. In addition, individual-level correlations of estimated and measured 24-hour urine sodium excretion were modest. Properly applied, the results will facilitate tracking of dietary sodium intake within populations over time and identification of communities for which dietary sodium restriction is most likely to be beneficial. Further work is needed to extend estimation to additional populations and improve individual-level assessment.

Iodine status of pregnant women in Sri Lanka

Based on new evidence and lessons learned within the last decade, pregnant women may not receive adequate iodized salt where the coverage of universal salt iodisation is poor. World Health Organisation has stated this could jeopardize optimal brain development of the fetus. This study was aimed to assess the iodine status of pregnant women in Sri Lanka. A cross-sectional clinic based nationally representative study was conducted. Three randomly selected antenatal clinics from each province, 30 randomly selected pregnant women from each selected clinic were included in the study. A total of 739 pregnant women were studied and casual urine samples collected to estimate iodine levels. Median urinary iodine levels in pregnant women was 113.7 g/L, which is far below the WHO recommendation between 150 and 249 μg/L indicating inadequate iodine status of pregnant women in Sri Lanka. Urine iodine distribution indicated 61.3%, 21.7%, 15.2% and 1.8% of pregnant women had an inadequate, adequate, above requirement and excessive intake respectively. Urinary iodine concentration significantly decreased with advancing pregnancy. Inadequate iodine intake was evident in 47.4%, 60.2% and 68.8% of pregnant women in the first, second and third trimester respectively. In conclusion, there is an urgent need to identify a programme to provide adequate iodine to pregnant women to ensure optimum fetal brain development. DOI: http://dx.doi.org/10.4038/sjdem.v3i1.5469 Sri Lanka Journal of Diabetes, Endocrinology and Metabolism 2013; 3 : 4-7

Assessment of iodine nutrition in pregnant north Indian subjects in three trimesters

Objective:The cross-sectional study was carried out to assess the iodine status of pregnant women, using median urinary iodine concentration (MUI) as the measure of outcome, to document the impact of advancing gestation on the MUI in normal pregnancy.Materials and Methods:The present study assessed the MUI in casual urine samples from 50 pregnant subjects of each trimester and 50 age-matched non-pregnant controls.Results:The median (range) of urinary iodine concentration (UIC) in pregnant women was 304 (102-859) μg/L and only 2% of the subjects had prevalence of values under 150 μg/L (iodine insufficiency). With regard to the study cohort, median (range) UIC in the first, second, and third trimesters was 285 (102-457), 318 (102-805), and 304 (172-859) μg/L, respectively. Differences between the first, second, and third trimesters were not statistically significant. The MUI in the controls (305 μg/L) was not statistically different from the study cohort.Conclusion:The pregnant women had no iodine deficiency, rather had high median urinary iodine concentrations indicating more than adequate iodine intake. Larger community-based studies are required in iodine-sufficient populations, to establish gestation-appropriate reference ranges for UIC in pregnancy.

Excessive iodine intake, water chemicals and endemic goitre in a Sudanese coastal area.

To study the associations between intakes of iodine and water chemicals and the thyroid gland status of schoolchildren living in the coastal city of Port Sudan. In our previous nationwide study on goitre, it was observed that the prevalence of goitre was high in Port Sudan city despite high urinary iodine excretion. A cross-sectional study including schoolchildren aged 6–12 years was designed. Measurements determined the prevalence of goitre, urinary iodine concentration and thiocyanate secretion in casual urine samples, serum levels of thyroxine, triiodothyronine, thyroid-stimulating hormone and thyroglobulin, as well as the levels of Cl⁻, F⁻, Ca²⁺, Mg²⁺ and total hardness of drinking water. Schoolchildren (n 654) aged 6–12 years. Port Sudan city is located at the western bank of the Red Sea. The city is surrounded by a mountainous area known as the Red Sea Hills. It is the main sea port in the Sudan, inhabited by ethnically and socio-economically heterogeneous populations. The prevalence of goitre in Port Sudan was 34.86% while the median urinary iodine concentration was 46,4μg/dl. Out of thirty-one pupils from Port Sudan, twenty-four (77.42 %) were found to have urinary iodine concentration greater than 30μg/dl and twelve (38.71 %) had different degrees of biochemical hypothyroidism. Excessive concentrations of Cl⁻, Ca²⁺, Mg²⁺ and water hardness (369.2, 116.48, 60.21 and 539.0mg/l, respectively) were detected in drinking water samples collected from Port Sudan that exceeded levels permitted by the WHO. The coastal city of Port Sudan is a goitre-endemic area. In contrast to other Sudanese cities in which endemic goitre is related to iodine deficiency, goitre in Port Sudan is associated with iodine excess. Water chemicals seemed to have no effects on thyroid status.

Mandatory fortification of bread with iodised salt modestly improves iodine status in schoolchildren

Iodine deficiency has re-emerged in many parts of the world including the UK, Australia and New Zealand (NZ). In 2009, the NZ government introduced the mandatory fortification of bread with iodised salt as a strategy to improve iodine intakes. The aim of the present study was to assess the impact of fortification on the iodine status of NZ schoolchildren. A school-based cluster survey was used to randomly select schools from two NZ cities. Children aged 8-10 years were administered a general questionnaire, and asked to provide a casual urine and finger-prick blood sample. The median urinary iodine concentration (UIC) of the children (n 147) was 113 μg/l, which falls between 100 and 199 μg/l indicating adequate iodine status; 12 % of children had a UIC < 50 μg/l and 39 % had a UIC < 100 μg/l. The median serum thyroxine concentration was 115 nmol/l. The median serum thyroglobulin (Tg) concentration was 10.8 μg/l and falls in the 10.0-19.9 μg/l range indicative of mild iodine deficiency, suggesting that these children still had enlarged thyroid glands. When compared with the median UIC of 68 μg/l reported in the 2002 NZ Children's Nutrition Survey, the UIC of children in the present study had increased, which is probably caused by the addition of iodised salt to bread. However, the elevated concentration of Tg in these children suggests that the increase in UIC is not sufficient to ensure that thyroid volume has normalised. The fortification of other staple foods, in addition to bread, should be considered to ensure good iodine status in NZ children.

A comprehensive assessment of urinary iodine concentration and thyroid hormones in New Zealand schoolchildren: a cross-sectional study

BackgroundInsufficient iodine in children’s diets is of concern because thyroid hormones are needed for normal growth and development, particularly of the brain. This study aimed to carry out a comprehensive assessment of the iodine status of New Zealand schoolchildren using a range of biochemical indices suitable for populations (i.e. urinary iodine concentration) and individuals (i.e. thyroid hormones).MethodsThe New Zealand National Children’s Nutrition Survey was a cross­‒sectional survey of a representative sample of schoolchildren aged 5­‒14 years. Children were asked to provide a casual urine sample for the determination of urinary iodine concentration (UIC) and a blood sample for the determination of thyroglobulin (Tg), Thyroid Stimulating Hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3).ResultsThe median UIC was 68 μg/L (n = 1153), which falls between 50­‒99 μg/L indicative of mild iodine deficiency. Furthermore, 29% of children had an UIC <50 μg/L and 82% had an UIC <100 μg/L. The median Tg concentration was 12.9 μg/L, which also falls between 10.0­‒19.9 μg/L indicative of mild iodine deficiency. The Tg concentration of children with an UIC <100 μg/L was 13.9 μg/L, higher than the 10.3 μg/L in children with an UIC >100 μg/L (P = 0.001). The mean TSH (1.7 mU/L), fT4 (14.9 pmol/L), and fT3 (6.0 pmol/L) concentrations for these mildly iodine deficient New Zealand children fell within normal reference ranges.ConclusionsThe UIC and Tg concentration indicate that New Zealand schoolchildren were mildly iodine deficient according to WHO/UNICEF/ICCIDD, and both are suitable indices to assess iodine status in populations or groups. The normal concentrations of TSH, fT4 and fT3 of these children suggest that these thyroid hormones are not useful indices of mild iodine deficiency.

Response to comments on urine iodine excretion in patients with euthyroid nodular disease

Response to comments on urine iodine excretion in patients with euthyroid nodular disease

Excessive iodine intake in schoolchildren

Inadequate iodine intake may result in iodine deficiency disorders (IDD). Thus, for more than 50 years, policies for the regulation of salt fortification with iodine have existed in Brazil. In 2003, a study on 6-14-year-old schoolchildren from regions of the state of São Paulo showed a median urinary iodine concentration of 360 μg/L. The objective of the present study was to assess the iodine nutrition status among schoolchildren. The study was conducted on 828 schoolchildren aged 4-13 years from eight schools in the interior of the state of São Paulo. A casual urine sample was collected from each volunteer for iodine determination by the adapted method of Sandell-Kalthoff. Only 1.9% (n = 16) of the children evaluated had low values of urinary iodine (<100 μg/L), while 24.6% had urinary iodine excretion values between 200 and 300 μg/L, and 67.1% had values above >300 μg/L. The results show that the iodine nutritional status of the schoolchildren studied is characterized by a high urinary iodine excretion, which might reveal an increase in iodine consumption by this population.

Use of iodized salt in the households improves the iodine status of pregnant women and school-age children in Donetsk, Ukraine: A double-blind randomized controlled trial

This study analyzed the effect of iodized salt consumption on the iodine status of pregnant women and school children living in the households of Donetsk, Ukraine. 160 households with a healthy pregnant woman and a child aged 6–12 years were assigned in concealed sequence 1 : 1 to the use of either common or iodized salt. Casual urine samples were collected and the consumption of specific foods was obtained verbally from the women and the children during a baseline and a follow-up visit in each household. All the women (age 30 years; pregnancy duration 20 weeks) and the children (age 8.5 years) completed the trial without any adverse event. At the baseline visit, the mean household salt iodine content was 10.2 mg/kg (SD 3.1) and the median urinary iodine (UI) concentration in the women (89 μg/L) and the children (101 μg/L) was not significantly different. The salt iodine content during the trial in the experimental households was 43.3 mg/kg (SD 4.6) and starkly higher (p<0.001) than in comparison house- holds (11.4 mg/kg; SD 5.1). The final UI of the pregnant women (141μg/L; 95% CI: 123–163) in experimental households was lower (p < 0.05) than of the children (169μg/L; 95% CI: 147–194), but the net effect of iodized salt consumption on the UI levels of the women (73μg/L; 95% CI: 66–81) was significantly higher (p<0.01) than that of the children (59μg/L; 95% CI: 53–67). The baseline UI (in both groups), and the consumption of marine fish (both groups) and of dairy products other than cheese (in children) were significant effect modifiers. Introduction of iodized salt in the households of Donetsk was associated with adequate iodine intake in school-age children but it did not realize sufficient iodine intake in pregnant women, despite the greater net effect on the UI concentration in the latter group.