Iodine status of postpartum women and their infants aged 3, 6 and 12 months: Mother and Infant Nutrition Investigation (MINI).

To alleviate the re-emergence of iodine deficiency in New Zealand, two strategies, the mandatory fortification of bread with iodised salt (2009) and a government-subsidised iodine supplement for breast-feeding women (2010), were introduced. Few studies have investigated mother and infant iodine status during the first postpartum year; this study aimed to describe iodine status of mothers and infants at 3, 6 and 12 months postpartum (3MPP, 6MPP and 12MPP, respectively). Partitioning of iodine excretion between urine and breast milk of exclusive breast-feeding (EBF) women at 3MPP was determined. In total, eighty-seven mother-infant pairs participated in the study. Maternal and infant spot urinary iodine concentration (UIC) and breast milk iodine concentration (BMIC) were determined. The percentage of women who took iodine-containing supplements decreased from 46 % at 3MPP to 6 % at 12MPP. Maternal median UIC (MUIC) at 3MPP (82 (46, 157) µg/l), 6MPP (85 (43, 134) µg/l) and 12MPP (95 (51, 169) µg/l) were <100 µg/l. The use of iodine-containing supplements increased MUIC and BMIC only at 3MPP. Median BMIC at all time points were below 75 µg/l. Infant MUIC at 3MPP (115 (69, 182) µg/l) and 6MPP (120 (60, 196) µg/l) were below 125 µg/l. Among EBF women at 3MPP, an increased partitioning of iodine into breast milk (highest proportion 60 %) was shown at lower iodine intakes, along with a reduced fractional iodine excretion in urine (lowest proportion 40 %), indicating a protective mechanism for breastfed infants' iodine status. In conclusion, this cohort of postpartum women was iodine-deficient. Iodine status of their breastfed infants was suboptimal. Lactating women who do not consume iodine-rich foods and those who become pregnant again should take iodine-containing supplements.

Food sources of iodine in schoolchildren and relationship with 24-h urinary iodine excretion in Victoria, Australia.

Dietary recalls have been used previously to identify food sources of iodine in Australian schoolchildren. Dietary assessment can provide information on the relative contributions of individual food groups which can be related to a robust objective measure of daily intake (24-h urinary iodine excretion (UIE)). In Australia, the government has mandated the use of iodised salt in breadmaking to address iodine deficiency. The aim of this study was to determine the dietary intake and food sources of iodine to assess their contribution to iodine excretion (UIE) in a sample of Australian schoolchildren. In 2011-2013, UIE was assessed using a single 24-h urine sample and dietary intake was assessed using one 24-h dietary recall in a convenience sample of primary schoolchildren from schools in Victoria, Australia. Of the 454 children with a valid recall and urine sample, 55 % were male (average age 10·1 (1·3 (sd) years). Mean UIE and dietary iodine intake were 108 (sd 54) and 172 (sd 74) µg/d, respectively. Dietary assessment indicated that bread and milk were the main food sources of iodine, contributing 27 and 25 %, respectively, to dietary iodine. Milk but not bread intake was positively associated with UIE. Multiple regression (adjusted for school cluster, age and sex) indicated that for every 100 g increase in milk consumption, there was a 3 µg/d increase in UIE (ß = 4·0 (se 0·9), P < 0·001). In conclusion, both bread and milk were important contributors to dietary iodine intake; however, consumption of bread was not associated with daily iodine excretion in this group of Australian schoolchildren.

A systematic review and meta-analysis of 24-h urinary output of children and adolescents: impact on the assessment of iodine status using urinary biomarkers.

PURPOSE: Urinary iodine concentration (UIC (µg/ml) from spot urine samples collected from school-aged children is used to determine the iodine status of populations. Some studies further extrapolate UIC to represent daily iodine intake, based on the assumption that children pass approximately 1 L urine over 24-h, but this has never been assessed in population studies. Therefore, the present review aimed to collate and produce an estimate of the average 24-h urine volume of children and adolescents (> 1 year and < 19 years) from published studies. METHODS: EBSCOHOST and EMBASE databases were searched to identify studies which reported the mean 24-h urinary volume of healthy children (> 1 year and < 19 years). The overall mean (95% CI) estimate of 24-h urine volume was determined using a random effects model, broken down by age group. RESULTS: Of the 44 studies identified, a meta-analysis of 27 studies, with at least one criterion for assessing the completeness of urine collections, indicated that the mean urine volume of 2-19 year olds was 773 (654, 893) (95% CI) mL/24-h. When broken down by age group, mean (95% CI) 24-h urine volume was 531 mL/day (454, 607) for 2-5 year olds, 771 mL/day (734, 808) for 6-12 year olds, and 1067 mL/day (855, 1279) for 13-19 year olds. CONCLUSIONS: These results demonstrate that the average urine volume of children aged 2-12 years is less than 1 L, therefore, misclassification of iodine intakes may occur when urine volumes fall below or above 1 L. Future studies utilizing spot urine samples to assess iodine status should consider this when extrapolating UIC to represent iodine intakes of a population.

Iodine-fortified toddler milk improves dietary iodine intakes and iodine status in toddlers: a randomised controlled trial.

PURPOSE: We aimed to evaluate the effectiveness of consuming iodine-fortified toddler milk for improving dietary iodine intakes and biochemical iodine status in toddlers. METHODS: In a 20-week parallel randomised controlled trial, healthy 12-20-month-old children were assigned to: Fortified Milk [n = 45; iodine-fortified (21.1 µg iodine/100 g prepared drink) cow's milk], or Non-Fortified Milk (n = 90; non-fortified cow's milk). Food and nutrient intakes were assessed with 3-day weighed food records at baseline, and weeks 4 and 20. Urinary iodine concentration (UIC) was measured at baseline and 20 weeks. RESULTS: At baseline, toddlers' median milk intake was 429 g/day. There was no evidence that milk intakes changed within or between the groups during the intervention. Toddlers' baseline geometric mean iodine intake was 46.9 µg/day, and the median UIC of 43 µg/L in the Fortified Milk group and 55 µg/L in the Non-Fortified Milk group indicated moderate and mild iodine deficiency, respectively, with this difference due to chance. During the intervention, iodine intakes increased by 136% (p < 0.001) and UIC increased by 85 µg/L (p < 0.001) in the Fortified Milk group compared to the Non-Fortified Milk group. The 20-week median UIC was 91 µg/L in the Fortified Milk group and 49 µg/L in the Non-Fortified Milk group. CONCLUSIONS: Consumption of ≈ 1.7 cups of iodine-fortified toddler milk per day for 20 weeks can increase dietary iodine intakes and UIC in healthy iodine-deficient toddlers. This strategy alone is unlikely to provide sufficient intake to ensure adequate iodine status in toddlers at risk of mild-to-moderate iodine deficiency.

Association Between Maternal Iodine Intake in Pregnancy and Childhood Neurodevelopment at Age 18 Months.

There are limited and inconsistent data suggesting that mild iodine deficiency in pregnancy might be associated with poorer developmental outcomes in children. Between 2011 and 2015, we conducted a prospective cohort study in Australia examining the relationship between maternal iodine intake in pregnancy and childhood neurodevelopment, assessed using Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III), in 699 children at 18 months. Maternal iodine intake and urinary iodine concentration (UIC) were assessed at study entry (<20 weeks' gestation) and at 28 weeks' gestation. Maternal iodine intake in the lowest (<220 µg/day) or highest (≥391 µg/day) quartile was associated with lower cognitive, language, and motor scores (mean differences ranged from 2.4 (95% confidence interval (CI): 0.01, 4.8) to 7.0 (95% CI: 2.8, 11.1) points lower) and higher odds (odds ratios ranged from 2.7 (95% CI: 1.3, 5.6) to 2.8 (95% CI: 1.3, 5.7)) of cognitive developmental delay (Bayley-III score <1 SD) compared with mothers with an iodine intake in the middle quartiles. There was no association between UIC in pregnancy and Bayley-III outcomes regardless of whether UIC and the outcomes were analyzed as continuous or categorical variables. Both low and high iodine intakes in pregnancy were associated with poorer childhood neurodevelopment in this iodine-sufficient population.

Sleep timing is associated with diet and physical activity levels in 9-11-year-old children from Dunedin, New Zealand: the PEDALS study.

It is well documented that short sleep duration is associated with excess body weight and poor food intake in children. It has been suggested that sleep timing behaviour may also be an important predictor of weight and other related behaviours, independent of sleep duration; however, there is a lack of research investigating these relationships. The present study investigated sleep timing in association with diet and physical activity levels in 439 children aged 9-11 years old from New Zealand. Sleep and physical activity data were collected using accelerometry, and food choice using a short food-frequency questionnaire. Participants were classified into one of four sleep timing behaviour categories using the median split for sleep-onset and -offset times. Differences between sleep timing groups for weekly consumption frequency of selected food groups, dietary pattern scores and minutes of moderate-to-vigorous physical activity were examined. Children in the late sleep/late wake category had a lower 'Fruit & Vegetables' pattern score [mean difference (95% CI): -0.3 (-0.5, -0.1)], a lower consumption frequency of fruit and vegetables [mean weekly difference (95% CI): -2.9 (-4.9, -0.9)] and a higher consumption frequency of sweetened beverages [mean weekly difference (95% CI): 1.8 (0.2, 3.3)] compared with those in the early sleep/early wake category. Additionally, children in the late sleep/late wake category accumulated fewer minutes of moderate-to-vigorous physical activity per day compared with those in the early sleep/early wake category [mean difference (95% CI): -9.4 (-15.3, -3.5)]. These findings indicate that sleep timing, even after controlling for sleep duration, was associated with both food consumption and physical activity.

The sensitivity and specificity of thyroglobulin concentration using repeated measures of urinary iodine excretion.

PURPOSE: Iodine deficiency affects 30% of populations worldwide. The amount of thyroglobulin (Tg) in blood increases in iodine deficiency and also in iodine excess. Tg is considered as a sensitive index of iodine status in groups of children and adults, but its usefulness for individuals is unknown. The aim of this study was to determine the diagnostic performance of Tg as an index of iodine status in individual adults. METHODS: Adults aged 18-40 years (n = 151) provided five spot urine samples for the measurement of urinary iodine concentration expressed as µg/L (UIC), µg/g of creatinine (I:Cre), and µg/day (estimated UIE); the mean of the five samples was used as the reference standard. Participants also provided a blood sample for the determination of Tg, thyroid-stimulating hormone (TSH), and free thyroxine (FT4). RESULTS: The median of UIC, I:Cre, estimated UIE, and Tg was 72 (range 16-350) µg/L, 90 (range 33-371) µg/g, 129 (range 41-646) µg/day, and 16.4 (range 0.8-178.9) µg/L, respectively. Using Tg cut-offs of >10, >11, >13, and >15 µg/L, the sensitivity and specificity for UIC, I:Cre, and estimated UIE ranged from 52 to 79% and 20-48%, respectively, below the acceptable value of ≥80%. Furthermore, receiver-operating characteristic (ROC) curves for Tg using the three measurements of urinary iodine were situated close to the chance line and the area under the curve ranged from 0.49 to 0.52. CONCLUSIONS: The results from this cross-sectional study indicate that Tg has low sensitivity and specificity to repeated measures of urinary iodine excretion. Further studies are still needed to investigate the usefulness of Tg as a biomarker of individual iodine status.

Maternal adherence with recommendations for folic acid and iodine supplements: A cross-sectional survey.

We conducted a survey of 535 New Zealand women to determine supplement use pre-pregnancy, during pregnancy and while breastfeeding to evaluate adherence with national recommendations for folic acid and iodine supplementation. Our findings suggest that despite these women being well-educated and motivated to complete an online survey, there was low adherence to recommendations for folic acid and iodine supplements. Only 38% of women reported supplement intake that met both folic acid and iodine recommendations. This cross-sectional survey provides information useful to policy makers, clinicians and researchers seeking to protect and promote maternal and infant health.

Urinary iodine concentration of New Zealand adults improves with mandatory fortification of bread with iodised salt but not to predicted levels.

PURPOSE: To measure the iodine status and iodine intake of New Zealand adults 18-64 years of age following mandatory fortification of bread with iodine. METHODS: A cross-sectional survey of NZ adults living in Dunedin and Wellington during February-November 2012. Three hundred and one men and women aged 18-64 years randomly selected from the New Zealand Electoral Roll completed a 24-h urine collection, a demographic and iodine-specific food frequency questionnaire (FFQ), and had height and weight measured. Urine collections were analysed for iodine and reported as median urinary iodine concentration (UIC) µg/L and median urinary iodine excretion (UIE) µg/day. The FFQ was used to estimate iodine intake with and without discretionary iodised salt use. RESULTS: The median UIC for all adults was 73 µg/L, indicative of mild iodine deficiency. The mean urinary volume was 2.0 L. As an estimate of iodine intake, the median UIE was 127 µg/day. Estimated iodine intake, using the FFQ which included discretionary iodised salt use, was 132 µg/day. Iodine intakes were associated with UIC (P = 0.040) and UIE (P = 0.003), but not with bread iodine intake and iodised salt use. CONCLUSION: Using the WHO/UNICEF/ICCIDD target for iodine sufficiency (a UIC of >100 µg/L) based on school-aged children with a mean urinary volume of 1.0 L, the iodine status of NZ adults does not reach adequate levels (73 µg/L). A more realistic parameter in a population with a higher urinary volume excretion (2.0 L) is the UIE. A median UIE of 127 µg/day suggests that the iodine status of NZ adults is now likely to be adequate.

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.

BACKGROUND: Insufficient 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). METHODS: The 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). RESULTS: The 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. CONCLUSIONS: The 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.

The quantification of sodium intake from discretionary salt intake in New Zealand using the lithium-tagged salt method.

Introduction: Discretionary salt (added in cooking at home or at the table) is a source of sodium and iodine in New Zealand. The amount of discretionary salt consumed in a population has implications on policies regarding sodium and iodine. Sodium intake from discretionary salt intake has not been quantified in New Zealand. The aim of this study was to estimate the proportion of total sodium that comes from discretionary salt in adults using the lithium-tagged salt method. Methods: A total of 116 healthy adults, who were not pregnant or breastfeeding, regularly consume home-cooked meals and use salt during cooking or at the table, aged 18-40 years from Dunedin, New Zealand were recruited into the study. The study took place over a 9-day period. On Day 1, participants were asked to collect a baseline 24-h urine to establish their normal lithium output. From Day 2 to Day 8, normal discretionary salt was replaced with lithium-tagged salt. Between Day 6 and Day 8, participants collected another two 24-h urine samples. A 24-h dietary recall was conducted to coincide with each of the final two 24-h urine collections. Urinary sodium was analysed by Ion-Selective Electrode and urinary lithium and urinary iodine were analysed using Inductively Coupled Plasma Mass Spectrometry. The 24-h dietary recall data was entered into Xyris FoodWorks 10. All statistical analysis were conducted using Stata 17.0. Results: A total of 109 participants with complete 24-h urine samples were included in the analysis. From the 24-h urine collections, the median urinary excretion of sodium and iodine was 3,222 mg/24 h (25th, 75th percentile: 2516, 3969) and 112 µg/24 h (82, 134). The median estimated sodium intake from discretionary salt was 13% (25th, 75th percentile: 7, 22) of the total sodium intake or 366 mg/24 h (25th, 75th percentile: 186, 705). Conclusion: The total sodium intake was higher than the suggested dietary target of 2,000 mg/day. In this sample of healthy adults 18 to 40 years old, 13% of total sodium intake derived from discretionary salt. Discretionary salt is an additional source of iodine if iodised salt is used. Policies to reduce sodium intake is recommended to include a range of strategies to target discretionary and non-discretionary sources of salt and will need to take into account the contribution of iodine from discretionary salt intake.

A Qualitative Study of Parental Perceptions of Baby Food Pouches: A Netnographic Analysis.

Globally, a recent phenomenon in complementary feeding is the use of squeezable baby food pouches. However, some health agencies have raised concerns about their possible long-term health effects. The aim of this study was to describe parental perceptions of the use of baby food pouches during complementary feeding (i.e., the transition from an entirely milk-based diet to solid foods) using a netnographic analysis of discussions on publicly available forums. In this study, the community was parents of young children. Six parenting forums were identified through a Google search using defined selection criteria. Discussion threads relating to baby food pouches were collected and imported into NVivo12 for thematic analysis via inductive reasoning. Perceptions of baby food pouches fell within two broad categories-benefits and concerns. The most commonly reported themes related to benefits were: convenience, health, baby enjoys, variety, and cost; whereas the most common concerns reported were: health, cost, lack of dietary exposure, dependence, and waste. Many parents reported both benefits and concerns. Once research has determined the long-term effect of using pouches on infants' health regarding eating habits, nutritional status, growth, and development, the findings of this study can inform educational strategies to either encourage or discourage their use.

Iodine status in a Sherpa community in a village of the Khumbu region of Nepal.

OBJECTIVE: To assess the iodine status of Sherpa residents living in Kunde village, Khumbu region, Nepal. DESIGN: Prevalence of goitre was determined by palpation. Urinary iodine concentrations (UIC) were determined in casual morning samples, and thyroid-stimulating hormone (TSH) in finger-prick blood samples on filter paper. Dietary and demographic data were obtained via questionnaire, and selected foods analysed for iodine. SETTING: Khumbu region is an area of low soil iodine in Nepal, where the prevalence of goitre was greater than 90% in the 1960s prior to iodine intervention. SUBJECTS: Two hundred and fifteen of 219 permanent residents of Kunde were studied. RESULTS: Overall prevalence of goitre was 31% (Grade 1 goitre, 27.0%; Grade 2, 4.2%). When adjusted to a world population, goitre prevalence was 27% (95% CI 23, 32%); Grade 2 goitre prevalence was 2.8% (95% CI 1.0, 4.6%). Median UIC was 97 microg/l, but only 75 microg/l in women of childbearing age. Thirty per cent had UIC < 50 microg/l and 52% had UIC < 100 microg/l, while 31% of children aged <14 years had UIC > 300 microg/l. Ten per cent of participants had TSH concentrations >5 microU/ml. CONCLUSIONS: The prevalence of severe iodine deficiency has decreased since the 1960s, but mild iodine deficiency persists, particularly in women of childbearing age. The consumption of high-iodine uncooked instant noodles and flavour sachets by school-aged children contributed to their low prevalence of goitre and excessive UIC values. This finding may obscure a more severe iodine deficiency in the population, while increasing the risk of iodine-induced hyperthyroidism in children. Ongoing monitoring is essential.

Development of Databases on Iodine in Foods and Dietary Supplements.

Iodine is an essential micronutrient required for normal growth and neurodevelopment; thus, an adequate intake of iodine is particularly important for pregnant and lactating women, and throughout childhood. Low levels of iodine in the soil and groundwater are common in many parts of the world, often leading to diets that are low in iodine. Widespread salt iodization has eradicated severe iodine deficiency, but mild-to-moderate deficiency is still prevalent even in many developed countries. To understand patterns of iodine intake and to develop strategies for improving intake, it is important to characterize all sources of dietary iodine, and national databases on the iodine content of major dietary contributors (including foods, beverages, water, salts, and supplements) provide a key information resource. This paper discusses the importance of well-constructed databases on the iodine content of foods, beverages, and dietary supplements; the availability of iodine databases worldwide; and factors related to variability in iodine content that should be considered when developing such databases. We also describe current efforts in iodine database development in the United States, the use of iodine composition data to develop food fortification policies in New Zealand, and how iodine content databases might be used when considering the iodine intake and status of individuals and populations.

Iodine Intakes of Victorian Schoolchildren Measured Using 24-h Urinary Iodine Excretion.

Mandatory fortification of bread with iodized salt was introduced in Australia in 2009, and studies using spot urine collections conducted post fortification indicate that Australian schoolchildren are now replete. However an accurate estimate of daily iodine intake utilizing 24-h urinary iodine excretion (UIE µg/day) has not been reported and compared to the estimated average requirement (EAR). This study aimed to assess daily total iodine intake and status of a sample of primary schoolchildren using 24-h urine samples. Victorian primary school children provided 24-h urine samples between 2011 and 2013, from which urinary iodine concentration (UIC, µg/L) and total iodine excretion (UIE, µg/day) as an estimate of intake was determined. Valid 24-h urine samples were provided by 650 children, mean (SD) age 9.3 (1.8) years (n = 359 boys). The mean UIE of 4-8 and 9-13 year olds was 94 (48) and 111 (57) µg/24-h, respectively, with 29% and 26% having a UIE below the age-specific EAR. The median (IQR) UIC was 124 (83,172) µg/L, with 36% of participants having a UIC < 100 µg/L. This convenience sample of Victorian schoolchildren were found to be iodine replete, based on UIC and estimated iodine intakes derived from 24-h urine collections, confirming the findings of the Australian Health Survey.