Iodine deficiency in pregnant women living in the South East of the UK: the influence of diet and nutritional supplements on iodine status

Iodine nutrition among pregnant women in the Faroe Islands

Ensuring adequate iodine nutrition during pregnancy is crucial for fetal brain development. Thus, the WHO recommend monitoring iodine nutrition in pregnant women. With changing dietary habits and declining iodine intake in coastal populations, iodine nutrition in pregnant Faroese women was a focus in newly established pregnancy cohorts. This study aimed to monitor the iodine status of pregnant women in the Faroe Islands by assessing urinary iodine concentration (UIC) and maternal iodine intake. For 2 years, all pregnant women were invited to participate in a nationwide study. Participants completed questionnaires addressing personal and lifestyle factors, supplement intake and dietary habits, Additionally, they provided spot urine samples for UIC measurements. Iodine was measured spectrophotometrically using the ceri/arsen method after alkaline-ashing. Among the 1030 invited, 654 participated and 647 provided a spot-urine sample. The average age was 30·4 years (18–47 years). The overall median UIC was 110 µg/l, declined from 117 to 101 µg/l over 2 years (P = 0·004). UIC was significantly impacted by diet. Women consuming fish and eggs had a higher median UIC compared with those whose primary iodine source was dairy: fish-dinner, 151 µg/l; dairy products, 112 µg/l (P < 0·001). Furthermore, there was a positive association between maternal age, reported intake of iodine-containing supplements and the UIC. This nationwide study of pregnant Faroese women found UIC below the WHO-recommended cut-off for pregnant women and decreasing with time. This decline highlights the importance of continuous monitoring to prompty identify shifts in iodine status, enabling timely intervention to address emerging deficiencies.

Animal board invited review: Dietary transition from animal to plant-derived foods: Are there risks to health?

Animal-derived foods (ADFs) are a very varied group of foods, but many are nutrient rich and contain higher quality protein than provided by plant-derived foods such that a simple replacement of ADF protein is likely to lead to a reduction in overall protein quality. In addition, many ADFs are richer in some nutrients than plant-based foods (e.g. Fe, Ca) and these often have a higher bioavailability. ADFs also provide nutrients that plants cannot supply (e.g. vitamin B12) and some provide beneficial health functionality (e.g. hypotensive) which is not explained by traditional nutrition. However, there remains a good health reason to increase the proportion of plant-derived food in many diets to increase the intake of dietary fibre which is often consumed at very sub-optimal levels. It seems logical that the increased plant-derived foods should replace the ADFs that have the least benefit, the greatest risk to health and the highest environmental impact. Processed meat fits these characteristics and should be an initial target for replacement with plant-based based protein-rich foods that additionally provide the necessary nutrients and have high-quality dietary fibre. Processed meat covers a wide range of products including several traditional foods (e.g. sausages) which will make decisions on food replacement challenging. There is therefore an urgent need for research to better define the relative health risks associated with the range of processed meat-based foods. The aim of this review is to examine the evidence on the benefits and risks of this dietary transition including the absolute necessity to consider initial nutrient status before the replacement of ADFs is considered.

Dietary Intakes of Women with Gestational Diabetes Mellitus and Pregnancy Outcomes: A Prospective Observational Study

Purpose

Nutrient intake for pregnant women with gestational diabetes mellitus (GDM) is important to ensure satisfactory birth outcomes. This study aims to explore the dietary profiles of patients with GDM, compare the results with the Chinese dietary guidelines or Dietary Reference Intakes (DRIs) from China and investigate the relationship between maternal dietary intake and pregnancy outcomes.

Patients and Methods

A total of 221 patients with GDM in the second trimester were included in the cohort. Dietary intake data were collected using a 24-hour recall method for three consecutive days. The pregnancy outcomes of these participants were subsequently monitored. Both univariate logistic regression and multivariate logistic regression analyses were conducted to explore the associations between dietary intake variables or general characteristics variables and adverse pregnancy outcomes.

Results

Participants with adverse pregnancy outcomes showed a lower intake of iodine and vitamin D, a lower percentage of dietary energy intake from carbohydrates and a higher percentage of dietary energy intake from fats, compared to participants without adverse pregnancy outcomes. The gestational weight gain and family history of diabetes were associated with an increased risk of adverse pregnancy outcomes. Conversely, regular exercise, the intake of iodine and Vitamin D, and the percentage of dietary energy intake from carbohydrates were associated with a decreased risk.

Conclusion

The daily diet of pregnant women with GDM in China did not meet the dietary guidelines or DRIs. The low intake of Vitamin D and iodine, the low dietary carbohydrate ratio, family history of diabetes, lack of exercise, and high gestational weight gain were associated with increased risk of adverse pregnancy outcomes in pregnant women with GDM.

A comparison of the nutritional content and price between dairy and non-dairy milks and cheeses in UK supermarkets: A cross sectional analysis

Background: Non-Dairy (ND) food consumption is rapidly increasing in the UK and for many consumers plant-based diets are presumed to be healthier than standard diets. ND alternatives have different nutritional compositions, and their consumption could present challenges on a public-health level. Aim: To compare the price and nutritional composition of dairy and ND milks and cheeses in UK supermarkets. Methods: Macro and micronutrient data was recorded from Alpro's website and the 6 leading UK grocers for their own-label ND milks and cheeses. For missing micronutrient values the McCance & Widdowson's dataset was used. 99 total products were extracted: 57 ND milks, 7 dairy milks, 10 dairy cheeses and 25 ND cheeses. Dairy milk and cheese were used as control against which all ND products were compared. Results: Soya and coconut milks had lower values of carbohydrates, sugars, calcium, iodine, and potassium (p < 0.01) than dairy. Almond milk had lower values of carbohydrates (p = 0.01), sugars, calcium, iodine, and potassium (p < 0.01) compared to dairy milk. Protein was significantly (p < 0.01) lower for all ND except soya. Dairy cheeses had higher values for energy, protein, iodine, potassium, riboflavin, vitamin B12 and calcium (p < 0.01) than ND. Median prices were similar between dairy and ND milks, whereas ND cheeses were significantly more expensive compared to dairy (p < 0.01). Conclusions: ND alternatives fall short in several key nutrients compared to dairy. Fortification, accurate labelling and nutrition education are needed to help consumers make healthy and informed choices.

Iodine and plant-based diets: a narrative review and calculation of iodine content

An increasing number of food-based recommendations promote a plant-based diet to address health concerns and environmental sustainability in global food systems. As the main sources of iodine in many countries are fish, eggs and dairy products, it is unclear whether plant-based diets, such as the EAT-Lancet reference diet, would provide sufficient iodine. This is important as iodine, through the thyroid hormones, is required for growth and brain development; adequate iodine intake is especially important before, and during, pregnancy. In this narrative review, we evaluated the current literature and estimated iodine provision from the EAT-Lancet reference diet. There is evidence that those following a strict plant-based diet, such as vegans, cannot reach the recommended iodine intake from food alone and are reliant on iodine supplements. Using the EAT-Lancet reference diet intake recommendations in combination with iodine values from UK food tables, we calculated that the diet would provide 128 μg/d (85 % of the adult recommendation of 150 μg/d and 51–64 % of the pregnancy recommendation of 200–250 μg/d). However, if milk is replaced with unfortified plant-based alternatives, total iodine provision would be just 54 μg/d (34 % and 22–27 % of the recommendations for adults and pregnancy, respectively). Plant-based dietary recommendations might place consumers at risk of iodine deficiency in countries without a fortification programme and where animal products provide the majority of iodine intake, such as the UK and Norway. It is essential that those following a predominantly plant-based diet are given appropriate dietary advice to ensure adequate iodine intake.

Systematic review and meta-analysis of iodine nutrition in modern vegan and vegetarian diets

Vegan and vegetarian diets are widely supported and adopted, but individuals following such diets remain at greater risk of iodine deficiency. This systematic review and meta-analysis was conducted to assess the iodine intake and status in adults following a vegan or vegetarian diet in the modern day. A systematic review and quality assessment were conducted from October 2020 to December 2022 according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidance. Studies were identified in Ovid MEDLINE, Web of Science, PubMed, and Scopus. Eleven articles were eligible for review containing 4421 adults (aged ≥ 18 years). Vegan groups had the lowest median urinary iodine concentration (mUIC) (12·2/l). None of the dietary groups had mUIC within the optimal range for iodine status (100-200 µg/l) (WHO). Vegan diets had the poorest iodine intake (17·3 µg/d) and were strongly associated with lower iodine intake (P = < 0·001) compared with omnivorous diets. Lower intake in vegan diets was influenced by sex (P = 0·007), the presence of voluntary or absence of Universal Salt Iodisation (USI) programmes (P = 0·01 & P = < 0·001), and living in a country with adequate iodine nutrition (P = < 0·001). Vegetarians and particularly vegans living in countries with no current USI programme continue to have increased risk of low iodine status, iodine deficiency and inadequate iodine intake. Further research into the usefulness of mandatory fortification of vegan appropriate foods is required.

Association between urinary iodine excretion, genetic disposition and fluid intelligence in children, adolescents and young adults: the DONALD study

PURPOSE

Iodine deficiency increases the risk of cognitive impairment and delayed physical development in children. It is also associated with cognitive impairment in adults. Cognitive abilities are among the most inheritable behavioural traits. However, little is known about the consequences of insufficient postnatal iodine intake and whether the individual genetic disposition modifies the association between iodine intake and fluid intelligence in children and young adults.

METHODS

The cultural fair intelligence test was used to assess fluid intelligence in the participants of the DONALD study (n = 238; mean age, 16.5 [SD = 7.7] years). Urinary iodine excretion, a surrogate iodine intake marker, was measured in 24-h urine. Individual genetic disposition (n = 162) was assessed using a polygenic score, associated with general cognitive function. Linear regression analyses were conducted to determine whether Urinary iodine excretion was associated with fluid intelligence and whether this association was modified by individual genetic disposition.

RESULTS

Urinary iodine excretion above the age-specific estimated average requirement was associated with a five-point higher fluid intelligence score than that below the estimated average requirement (P = 0.02). The polygenic score was positively associated with the fluid intelligence score (β = 2.3; P = 0.03). Participants with a higher polygenic score had a higher fluid intelligence score.

CONCLUSION

Urinary iodine excretion above the estimated average requirement in childhood and adolescence is beneficial for fluid intelligence. In adults, fluid intelligence was positively associated with a polygenic score for general cognitive function. No evidence showed that the individual genetic disposition modifies the association between Urinary iodine excretion and fluid intelligence.

Inadequate Iodine Intake in Mothers of Young Children in Innlandet County, Norway

Background

Iodine has an essential role in child growth and brain development. Thus, sufficient iodine intake is particularly important in women of childbearing age and lactating women.

Objectives

This cross-sectional study aimed to describe iodine intake in a large random sample of mothers of young children (aged ≤2 y) living in Innlandet County, Norway.

Methods

From November 2020 to October 2021, 355 mother-child pairs were recruited from public health care centers. Dietary data were obtained using two 24-h dietary recalls (24-HRs) per woman and an electronic FFQ. The Multiple Source Method was used to estimate the usual iodine intake from the 24-HR assessment.

Results

Based on the 24-HRs, the median (P25, P75) usual iodine intake from food was 117 μg/d (88, 153) in nonlactating women and 129 μg/d (95, 176) in lactating women. The median (P25, P75) total usual iodine intake (from food combined with supplements) was 141 μg/d (97, 185) in nonlactating women and 153 μg/d (107, 227) in lactating women. Based on the 24-HRs, 62% of the women had a total iodine intake below the recommendations (150 μg/d in nonlactating women and 200 μg/d in lactating women), and 23% of them had an iodine intake below the average requirement (100 μg/d). The reported use of iodine-containing supplements was 21.4% in nonlactating women and 28.9% in lactating women. In regular users of iodine-containing supplements (n = 63), supplements contributed to an average of 172 μg/d of iodine. Among regular iodine supplement users, 81% reached the recommendations compared with 26% of nonsupplement users (n = 237). The iodine intake estimated by FFQ was substantially higher than that estimated by 24-HRs.

Conclusions

Maternal iodine intake in Innlandet County was inadequate. This study confirms the need for action to improve iodine intake in Norway, particularly among women of childbearing age.

Management of Hyperthyroidism during Pregnancy: A Systematic Literature Review

In pregnancy, several physiological changes affect maternal circulating thyroid hormone levels. The most common causes of hyperthyroidism in pregnancy are Graves' disease and hCG-mediated hyperthyroidism. Therefore, evaluating and managing thyroid dysfunction in women during pregnancy should ensure favorable maternal and fetal outcomes. Currently, there is no consensus regarding an optimal method to treat hyperthyroidism in pregnancy. The term "hyperthyroidism in pregnancy" was searched in the PubMed and Google Scholar databases to identify relevant articles published between 1 January 2010 and 31 December 2021. All of the resulting abstracts that met the inclusion period were evaluated. Antithyroid drugs are the main therapeutic form administered in pregnant women. Treatment initiation aims to achieve a subclinical hyperthyroidism state, and a multidisciplinary approach can facilitate this process. Other treatment options, such as radioactive iodine therapy, are contraindicated during pregnancy, and thyroidectomy should be limited to severe non-responsive thyroid dysfunction pregnant patients. In light of this events, even in the absence of guidelines certifying screening, it is recommended that all pregnant and childbearing women should be screened for thyroid conditions.

Improving Pregnant Women's Iodine Intake Estimates and Its Prevalence of Inadequacy through the Use of Salt and Seasoning Covariates

(1) Measuring usual iodine intake is a complex task due to the food consumption variability and its natural concentration in food. Therefore, the use of covariates to adjust statistical methods to estimate usual intake could improve the estimates obtained through dietary surveys. This study aims to evaluate the influence of salt and seasoning usage covariates on the estimates of usual iodine intake and the prevalence of its inadequacy. (2) A cross-sectional study was conducted with Brazilian pregnant women's food consumption data obtained with 24-h recall (n = 2247). The usual iodine intake was adjusted for intraindividual variability, supplement use, temporal effects, data collection methods, and sociodemographic characteristics with the tool UCD/NCI SIMPLE in the SAS software. Then, salt and seasoning usage covariates were used to adjust the distribution. The harmonized intake reference values for populations were used to assess intake adequacy. (3) The adjustments for salt and seasoning usage yielded a higher mean of usual iodine intakes. The only exception was the adjustment for the "habit of adding salt to meals after preparing/cooking", which produced a lower mean of usual intake and increased the prevalence of insufficient intake. (4) Salt and seasoning usage covariates affect the estimates evaluated. However, more studies are necessary to evaluate the influence observed.

Iodine status of pregnant women from the Republic of Cyprus

Iodine supply is crucial during pregnancy to ensure that the proper thyroid function of mother and baby support fetal brain development. Little is known about iodine status or its dietary determinants in pregnant women in the Republic of Cyprus. We therefore recruited 128 pregnant women at their first-trimester ultrasound scan to a cross-sectional study. We collected spot-urine samples for the measurement of urinary iodine concentration (UIC, µg/l) and creatinine concentration (Creat, g/l), the latter of which allows us to correct for urine dilution and to compute the iodine-to-creatinine ratio (UI/Creat). Women completed a FFQ and a general questionnaire. We used a General Linear model to explore associations between maternal and dietary characteristics with UI/Creat. The median UIC (105 µg/l) indicated iodine deficiency according to the WHO criterion (threshold for adequacy = 150 µg/l), and the UI/Creat was also low at 107 µg/g. Only 32 % (n 45) of women reported the use of iodine-containing supplements; users had a higher UI/Creat than non-users (131 µg/g v. 118 µg/g), though this difference was NS in the adjusted analysis (P = 0·37). Of the dietary components, only egg intake was significantly associated with a higher UI/Creat in adjusted analyses (P = 0·018); there was no significant association with milk, dairy products or fish intake. Our results suggest that pregnant women in Cyprus have inadequate iodine status and are at risk of mild-to-moderate iodine deficiency. Further research on dietary sources in this population is required.

Dietary Intakes of Folate, Vitamin D and Iodine during the First Trimester of Pregnancy and the Association between Supplement Use and Demographic Characteristics amongst White Caucasian Women Living with Obesity in the UK

Folate, vitamin D and iodine are key micronutrients in pregnancy, with deficiency associated with poor maternal and infant outcomes. For folate and vitamin D especially, deficiency is more common amongst women with obesity and recommended intakes and guidance on supplementation varies worldwide. The present study aims to investigate dietary and supplementary intakes of these micronutrients amongst a population of pregnant women with obesity in the United Kingdom, alongside key maternal demographic characteristics. Expectant women (n = 75) with a body mass index ≥ 30 kg/m² at first antenatal appointment were recruited at 12 weeks gestation. Participants were asked about their supplement use preconception and during trimester one in a baseline questionnaire which also asked about demographic characteristics. Women also completed a four day diet diary from which dietary and supplemental intakes of micronutrients intakes were estimated. Folic acid was taken by 96% of women at any point in trimester 1, whilst only 26% of women took the higher 5 mg dose recommended for women with obesity in the UK. For vitamin D and iodine, 56% and 44% of women met the UK RNI, respectively. Maternal age was positively associated with taking supplements of any kind and the 5 mg folic acid supplement, whilst parity was inversely associated with both outcomes. This study strengthens the rationale for further work to be done raising awareness of the need for women with obesity to supplement both with a higher dose of folic acid and vitamin D and to be aware of the role of iodine during pregnancy.

Contribution of base diet, voluntary fortified foods and supplements to micronutrient intakes in the UK

The objective of the present study was to evaluate the contribution of voluntary fortified foods and supplements to reducing micronutrient shortfalls in the UK population. A secondary analysis of the UK National Diet and Nutrition Survey was conducted (2012/13–2013/14, N 2546, 1·5–95 years). Micronutrient intakes were derived from food consumption intake data and food composition data and calculated as the proportion below or above the Dietary Reference Values for males and females of different age groups, for those on a base diet only, users of fortified foods but no supplements and users of fortified foods and supplements. Of the population consuming a base diet only, 21–45 % and 5–29 % fell below the Estimated Average Requirement (EAR) for minerals and vitamins, respectively. About 3–13 % fewer consumers of fortified foods fell below the EAR for vitamins and minerals. Supplements barely reduced the prevalence of intakes below the EAR. Among supplement non-users and users, 99 and 96 % failed to meet the reference intakes for vitamin D. More women than men were at risk of inadequacies of micronutrient intakes. The prevalence of inadequacies declined with increasing age. Voluntary fortified foods but not supplements made a meaningful contribution to intakes of vitamin and minerals, without risk of unacceptably high intakes. These insights may help the UK to define approaches to address micronutrients of concern in vulnerable groups.

Hypothyroidism

Hypothyroidism is the common clinical condition of thyroid hormone deficiency and, if left untreated, can lead to serious adverse health effects on multiple organ systems, with the cardiovascular system as the most robustly studied target. Overt primary hypothyroidism is defined as elevated thyroid-stimulating hormone (TSH) concentration in combination with free thyroxine (fT₄) concentration below the reference range. Subclinical hypothyroidism, commonly considered an early sign of thyroid failure, is defined by elevated TSH concentrations but fT₄ concentrations within the reference range. Hypothyroidism is classified as primary, central or peripheral based on pathology in the thyroid, the pituitary or hypothalamus, or peripheral tissue, respectively. Acquired primary hypothyroidism is the most prevalent form and can be caused by severe iodine deficiency but is more frequently caused by chronic autoimmune thyroiditis in iodine-replete areas. The onset of hypothyroidism is insidious in most cases and symptoms may present relatively late in the disease process. There is a large variation in clinical presentation and the presence of hypothyroid symptoms, especially in pregnancy and in children. Levothyroxine (LT4) is the mainstay of treatment and is one of the most commonly prescribed drugs worldwide. After normalization of TSH and fT₄ concentrations, a considerable proportion of patients treated with LT4 continue to have persistent complaints, compromising quality of life. Further research is needed regarding the appropriateness of currently applied reference ranges and treatment thresholds, particularly in pregnancy, and the potential benefit of LT4/liothyronine combination therapy for thyroid-related symptom relief, patient satisfaction and long-term adverse effects.

Thyroglobulin levels among iodine deficient pregnant women living in Northern Ireland

BACKGROUND

Iodine deficiency has re-emerged among pregnant cohorts in the UK. Thyroglobulin (Tg) is a protein produced uniquely by the thyroid gland which appears to mount a U-shaped response to extremes of iodine status. Tg has been suggested as an alternative marker for chronic iodine deficiency but the value of Tg in pregnancy has not been fully elucidated. A recent non-European study suggested a median Tg ≤10 µg/L with <3% of values >44 µg/L was indicative of sufficiency in the second trimester of pregnancy.

METHODS

We measured serum Tg levels in each trimester in 241 pregnant women living in Northern Ireland, a population with mild iodine deficiency at all stages of pregnancy as defined by urinary iodine concentration (UIC) and iodine: creatinine ratio (ICR). Women with Tg antibodies (6% in 1st trimester) were excluded.

RESULTS

The median UIC in this cohort was in the deficient range at 73, 94 and 117 µg/L in sequential trimesters (adequacy ≥ 150 µg/L). Corresponding median Tg levels were 19, 16 and 16 µg/L respectively. Median Tg for all samples was 17 μg/L (IQR 11-31) suggestive of iodine deficiency. Tg was >44 μg/L in 14.3%, 9.4% and 12.4% of women in sequential trimesters respectively. Women with either UIC/ICR below the cut-offs 150 µg/L and 150 µg/g creatinine had higher Tg concentrations in 1st and 2nd trimester (p < 0.01; p < 0.001) but not in 3rd trimester.

CONCLUSION

This study adds to the evolving evidence that Tg measurement is of value in reflecting iodine status in pregnancy.

Iodine status in pregnant women and infants in Finland

PURPOSE

Iodine insufficiency during pregnancy may adversely influence fetal growth and development. There is a lack of information on iodine status in pregnant women and infants in many countries including Finland. The aim of this study is to determine dietary intake of iodine and the iodine status in a population of Finnish pregnant women and their infants.

METHODS

Urine samples were collected from women participating in a mother-child clinical study at early (n = 174) and late pregnancy (n = 186) and at three months of postpartum (n = 197), when infant samples were also collected (n = 123). Urine iodine concentration was measured using inductively coupled plasma mass spectrometry. Cutoffs for iodine insufficiency were < 150 µg/L during pregnancy and < 100 µg/L at postpartum and in infants. Iodine intake was assessed using 3-day food diaries.

RESULTS

Increased risk of insufficiency, based on urinary iodine concentrations, was observed in the groups investigated in this study. Of the women studied, 66% had urinary iodine concentrations indicating insufficient intakes and iodine insufficiency at early pregnancy, 70% at late pregnancy and 59% at three months of postpartum. This was also the case in 29% of the three-month-old infants. Estimation of iodine intake revealed that iodine insufficient women had lower intakes of iodine from the diet, from food supplements and from diet plus supplements than iodine sufficient women in early pregnancy and at three months of post-partum. In late pregnancy, this difference was seen for iodine intake from supplements.

CONCLUSION

The majority of the women manifested with low urine iodine concentrations both during and after pregnancy. Similarly, one-third of the infants presented with iodine insufficiency. Maternal iodine intake data support these findings. These observations may have implications for optimal child cognitive development.

Vegans and vegetarians living in Nottingham (UK) continue to be at risk of iodine deficiency

Iodine is essential for thyroid hormone synthesis. Individuals adhering to vegan and vegetarian diets have been found to be vulnerable to iodine deficiency. Yet, iodine has not been monitored in these groups across time. This study aims to investigate iodine status, intake and knowledge in vegans, vegetarians and omnivores and determine changes between 2016-2017 and 2019. Dietary intake (µg/d) was estimated by 3-d food diaries and iodine FFQ. Urinary iodine concentration, analysed by inductively coupled plasma mass spectrometry, assessed iodine status according to WHO criteria. Iodine knowledge was scored by an adapted questionnaire. IBM SPSS was used for statistical analysis. Ninety-six adults (18-60 years) were recruited in October 2016-2017 (vegans: 12; vegetarians: 5; omnivores: 43) and June 2019 (vegans: 7; vegetarians: 10;omnivores: 19). Median dietary iodine was below the Reference Nutrient Intake for all groups. Vegans and vegetarians had the lowest iodine intake. Vegans had significantly lower iodine intake than omnivores (2016-2017, P = 0 032; 2019, P = 0 001). Omnivores had the highest iodine status (2016-2017, 79 4 µg/l; 2019, 72 4 µg/l) and vegans the lowest (2016-2017, 31 2 µg/l; 2019, 12 2 µg/l). Iodine knowledge was poor but did not differ between dietary groups (2016-2017, P = 0 219; 2019, P = 0 532). Vegans and vegetarians continue to be at risk of iodine deficiency. Further, iodine intake in the UK is poor independent of dietary choice. Iodine education is needed along with research into improving iodine nutrition at national level.

Dietary Quality of Women of Reproductive Age in Low-Income Settings: A Cross-Sectional Study in Kyrgyzstan

Dietary diversity and adequate nutrient intake are essential for conducting a healthy life. However, women in low-income settings often face difficulties in ensuring dietary quality. This research assessed relationships between the dietary diversity, nutrient adequacy, and socio-economic factors among women of reproductive age (WRA) in Kyrgyzstan. A cross-sectional study was undertaken in four locations, including two rural and two urban areas in the north and south of Kyrgyzstan. A survey with pre-coded and open-ended questions was employed during the interviews of 423 WRAs aged 18-49. Data collection was conducted in March-May 2021. The average value body mass index (BMI) of WRA was 24.2 ± 4.6 kg/m2. The dietary diversity score (DDS) was higher among rural women (common language effect size) cles = 0.67, adjusted p < 0.001) in the northern region (cles = 0.61, p < 0.05) who have cropland (cles = 0.60, p < 0.001) and a farm animal (cles = 0.60, p < 0.05). Mean nutrient adequacy ratio (NAR) was below 1 in most micronutrients, whereas thiamine, riboflavin, vitamins B6 and C, folic acid, calcium, and magnesium were even lower than 0.5. Women with a kitchen garden or a cropland had better NAR energy (cles = 0.57), NAR carbohydrate (cles = 0.60), NAR fiber (cles = 0.60), NAR vitamin B1 (cles = 0.53), and NAR folic acid (cles = 0.54). Respondents who receive remittances and a farm animal have better NARs for energy, carbohydrates, fiber, vitamin B1, folic acid, iron, zinc, and mean adequacy ratio for 16 nutrients (MAR 16) than those who do not. Education and income have a negative correlation with dietary quality. This study contributes to the limited literature on the quality of diets in Kyrgyzstan. Hidden hunger and undernutrition are a severe problem among WRA in low-income settings. Recommendations are including study programs in nutrition, teaching households farming practices, and raising awareness on adequate nutrition.

Environmental and human iodine and selenium status: lessons from Gilgit-Baltistan, North-East Pakistan

Iodine and selenium deficiencies are common worldwide. We assessed the iodine and selenium status of Gilgit-Baltistan, Pakistan. We determined the elemental composition (ICP-MS) of locally grown crops (n = 281), drinking water (n = 82), urine (n = 451) and salt (n = 76), correcting urinary analytes for hydration (creatinine, specific gravity). We estimated dietary iodine, selenium and salt intake. Median iodine and selenium concentrations were 11.5 (IQR 6.01, 23.2) and 8.81 (IQR 4.03, 27.6) µg/kg in crops and 0.24 (IQR 0.12, 0.72) and 0.27 (IQR 0.11, 0.46) µg/L in water, respectively. Median iodised salt iodine was 4.16 (IQR 2.99, 10.8) mg/kg. Population mean salt intake was 13.0 g/day. Population median urinary iodine (uncorrected 78 µg/L, specific gravity-corrected 83 µg/L) was below WHO guidelines; creatinine-corrected median was 114 µg/L but was unreliable. Daily selenium intake (from urinary selenium concentration) was below the EAR in the majority (46-90%) of individuals. Iodine and selenium concentrations in all crops were low, but no health-related environmental standards exist. Iodine concentration in iodised salt was below WHO-recommended minimum. Estimated population average salt intake was above WHO-recommended daily intake. Locally available food and drinking water together provide an estimated 49% and 72% of EAR for iodine (95 µg/day) and selenium (45 µg/day), respectively. Low environmental and dietary iodine and selenium place Gilgit-Baltistan residents at risk of iodine deficiency disorders despite using iodised salt. Specific gravity correction of urine analysis for hydration is more consistent than using creatinine. Health-relevant environmental standards for iodine and selenium are needed.

24 h urinary creatinine excretion during pregnancy and its application in appropriate estimation of 24 h urinary iodine excretion

BACKGROUND

Urinary creatinine can be used to adjust urinary iodine to evaluate iodine nutritional status during pregnancy. However, the reference intervals and impact factors of urinary creatinine are unknown.

METHODS

24 h urine creatinine concentration (24 hUCr) and spot UCr at four different time periods of the day of pregnant women from Part 1 (n = 743) were measured. Linear regression analysis was performed to identify the impact factors of 24 h urinary creatinine excretion (24 hUCrE) and obtain the estimated 24 h urinary creatinine excretion (24 hUCrE_est). Then measured urinary iodine concentration (UIC) of 24 h and at fasting of pregnant women from Part 2 (n = 325), used spot urinary iodine to creatinine concentration ratio (UIC/UCr) and 24 hUCrE_est to calculate the estimated 24 h urinary iodine excretion (24 hUIE_est), finally checked the consistency and correlation of 24 hUIE_est and 24 h urinary iodine excretion (24 hUIE).

RESULTS

In Part 1, the median 24 hUCrE was 1.24(IQR0.98-1.76)g, and the reference interval was 0.61-2.93 g. The median 24 hUCr was 0.76 (IQR0.57-1.01)g/L, and the reference interval was 0.36-1.88 g/L. Multiple linear regression results showed that pregnancy weight was an influencing factor to 24 hUCrE after adjusting by gestational weeks, age, pre-pregnancy BMI, and percentage of body fat (F = 45.029, p＜0.001). In Part 2, there was no statistically significant difference between 24 hUIE_est and 24 hUIE (Z =-0.767, p = 0.443). Using 24hUIE as the gold standard, the relative average difference in 24hUIE_est was 4.2 %, the relative average differences for UIC and UIC/UCr were 32.4 % and 37.2 %. The reference interval of 24 hUIE and 24 hUIE_est were 88.43-585.90 μg and 50.97-700.39 μg, respectively.

CONCLUSIONS

The reference intervals of 24 hUCrE, spot UCr, 24 hUIE, and 24 hUIE_est during pregnancy were established. 24 hUCrE has important application value in iodine nutrition evaluation to gain more lead time for pregnant women with iodine nutrition-related diseases.

Iodine monitoring models contribute to avoid adverse birth outcomes related more than adequate iodine intake

BACKGROUND

Iodine plays an important role in pregnancy. How to maintain adequate iodine intake amongst pregnant women in each trimester of pregnancy to prevent adverse birth outcomes in central China is a challenge for clinical practice.

METHODS

870 pregnant women and their infants were enrolled in the study. Urinary iodine concentration (UIC) was measured using an inductively coupled plasma mass spectrometry (ICP-MS). Maternal and newborn information were obtained during follow-up. Multinomial logistic regression models were established.

RESULTS

Median UIC of pregnant women was 172 ± 135 μg/L which is currently considered to be sufficient. Multivitamin supplements containing iodine, iodized salt intake and frequent milk intake were significantly associated with higher UIC. Multivariate logistic regression analysis showed that multivitamin supplements containing iodine and milk consumption were risk factors for more than adequate iodine (UIC ≥ 250 μg/L). Iodine-rich diet was significantly related to heavier birthweight, larger head circumference and longer femur length of the newborns while more than adequate iodine intake (UIC ≥ 250 μg/L) was a risk factor for macrosomia. Logistic regression models based on potential risk factors involving iodine containing supplements and iodine-rich diet were established to predict and screen pregnant women with high risk of more than adequate iodine intake among local pregnant women in different trimesters and guide them to supplement iodine reasonably to prevent the risk.

CONCLUSIONS

Multivitamin supplements containing iodine and milk consumption were risk factors for maternal UIC ≥ 250 μg/L which was a risk factor for macrosomia. Iodine monitoring models were established to provide guidance for pregnant women to reduce the risk of more than adequate iodine intake, thereby contributing to reduce the risk of having a macrosomia.

Nutritional Iodine Status in Pregnant Women from Health Area IV in Asturias (Spain): Iodised Salt Is Enough

Background: Iodine deficiency during pregnancy may have adverse effects on the neurodevelopment of the foetus. Recent studies of pregnant women in Asturias (Spain) indicate that nutritional iodine levels are sufficient. The objective of this study was to confirm the appropriate nutritional iodine status and to analyse the influence of the ingestion of iodine on maternal urinary iodine concentration (UIC) and thyroid function. Methods: An observational study was carried out between May and June 2017 on women in the first trimester of pregnancy from Health Area IV in Asturias. The women completed a questionnaire related to their consumption of iodine and samples were taken to analyse UIC and thyroid function. Results: Three hundred and eighteen pregnant women were involved. Of these, 51.10% used iodised salt, 48.90% consumed ≥ 2 servings of dairy products daily and 87.08% took iodine supplements. The median UIC was 171.5 μg/L (116–265 μg/L) and 60.41% of women had UIC ≥ 150 μg/L. Multivariate logistic regression analysis demonstrated that iodised salt had a protective effect on UIC < 150 μg/L (odds ratio (OR) 0.404 (0.237–0.683), p = 0.001), but not iodine supplements (OR 0.512 (0.240–1.085), p = 0.080). The average level of thyroid stimulating hormone (TSH) was 2.26 ± 0.94 mIU/L; 68.40% of pregnant women taking iodine supplements had TSH < 2.5 mIU/L compared to 30.00% of those who were not taking supplements (p = 0.031). Conclusions: The pregnant women in our health area are maintaining appropriate nutritional iodine levels. The consumption of iodised salt protects against iodine deficiency; thus, iodine supplements should be taken on an individualised basis.

Iron, iodine and vitamin D deficiencies during pregnancy: epidemiology, risk factors and developmental impacts

Micronutrient deficiency persists throughout the world, and although the burden is higher in low-resource settings, it is also prevalent in wealthy countries, a phenomenon termed 'hidden hunger'. Due to their high requirements for vitamins and minerals relative to their energy intake, young women and children are particularly vulnerable to hidden hunger. As they share several risk factors and impact on overlapping outcomes, we consider how deficiency of iron, iodine and vitamin D can have profound impacts on perinatal health and infant development. We review the epidemiology of these micronutrient deficiencies during pregnancy, including social, environmental and dietary risk factors. We identify the main challenges in defining nutritional status of these nutrients using validated diagnostic criteria linked with meaningful clinical outcomes. Public health strategies are urgently required to improve the overall health and nutritional status of women of reproductive age. Obesity prevention and early detection of malnutrition with standardised screening methods would detect pregnant women at increased risk of iron deficiency. Development of sensitive, individual biomarkers of iodine status is required to protect maternal health and fetal/infant brain development. Risk assessments of vitamin D requirements during pregnancy need to be revisited from the perspective of fetal and neonatal requirements. International consensus on standardised approaches to micronutrient assessment, analysis and reporting as well as sensitive, clinically validated infant and child neuro-behavioural outcomes will enable progression of useful observational and intervention studies.

Iodine status in UK-An accidental public health triumph gone sour

The improvement in iodine status among the UK population from the 1930s onwards has been described as an 'accidental public health triumph' despite the lack of any iodine fortification program. However, iodine deficiency in the UK has re-emerged in vulnerable groups and is likely due to a combination of changing farming practices, dietary preferences and public health priorities. The UK is now among only a minority of European countries with no legislative framework for iodine fortification. The experience of folic acid fortification and the 28-year delay in its implementation lays bare the political difficulties of introducing any fortification program in the UK. If iodine fortification is not an imminent possibility, then it is important to explore other options: how to change farming practice especially on organic farms; encourage dairy intake; protect and expand our public health programs of milk provision for vulnerable groups and embark on education programs for women of childbearing potential and healthcare professionals. This review explores how the UK may have arrived at this juncture and how the iodine status of the nation may be improved at this time of major political and public health upheaval.

Iodine status five years after the adjustment of universal salt iodization: a cross-sectional study in Fujian Province, China

Background

Universal salt iodization program was introduced to China to eliminate iodine deficiency disorders in 1995. In 2012, Fujian Province decreased the concentration of iodized table salt according to the national unified requirement. This study aimed to assess the effect on iodine status after the adjustment, providing evidence for further adjustment in Fujian Province.

Methods

Sampling units were selected by multistage cluster sampling method. In each sampling unit, table salt was collected from 30 households. A total of 2,471 people in 2009 and 4,806 people in 2017 provided urine samples and were included in this cross-sectional analysis. Median iodized salt concentration and median urine iodine concentration were present by median and interquartile range.

Results

Median iodized salt decreased from 29.8 mg/kg in 2009 to 23.9 mg/kg in 2017. The median urinary iodine concentrations for school-age children in 2017 in coastal urban area, non-coastal urban area, coastal rural area and non-coastal rural area were 163.6µg/L (interquartile range = 100.1–252.0µg/L), 198.9µg/L (interquartile range = 128.0-294.0µg/L), 181.8µg/L (interquartile range = 114.1–257.0µg/L) and 218.2µg/L (interquartile range = 148.1-306.5µg/L), respectively. The median urinary iodine concentrations for adults in 2017 in these areas were 151.1µg/L (interquartile range = 98.3-231.7µg/L), 168.7µg/L (interquartile range = 109.6–242.0µg/L), 167.7µg/L (interquartile range = 105.7-245.7µg/L) and 182.7µg/L (interquartile range = 117.1-258.9µg/L). The median urinary iodine concentrations for pregnant women in 2017 in these areas were 157.7µg/L (interquartile range = 106.9-223.8µg/L), 141.5µg/L (interquartile range = 97.7-207.6µg/L), 127.3µg/L (interquartile range = 90.0-184.5µg/L) and 144.8µg/L (interquartile range = 99.9-184.5µg/L). The median urinary iodine concentrations for lactating women in 2017 in these areas were 122.7µg/L (interquartile range = 84.1–172.0µg/L), 123.7µg/L (interquartile range = 70.7-184.7µg/L), 105.8µg/L (interquartile range = 67.1-152.3µg/L) and 110.2µg/L (interquartile range = 74.1-170.3µg/L).

Conclusions

The overall urinary iodine concentrations among school-age children, adults and lactating women dramatically decreased after implementing the new standard. Almost all of them were iodine adequate, suggesting we reached the expected aim of iodized salt adjustment. However, pregnant women were iodine insufficient after adjustment. Therefore, we should continue the surveillance of iodine status of populations and focus on the additional iodine supplement strategies for pregnant women.

Iodine knowledge is associated with iodine status in Portuguese pregnant women: results from the IoMum cohort study

Lack of knowledge about iodine has been suggested as a risk factor for iodine deficiency in pregnant women, but no studies have addressed this issue in Portugal. So, the aim of this study was to investigate iodine knowledge among Portuguese pregnant women and its association with iodine status. IoMum, a prospective observational study, included 485 pregnant women recruited at Centro Hospitalar e Universitário de S. João, Porto, between the 10th and 13th gestational weeks. Partial scores for knowledge on iodine importance, on iodine food sources or on iodised salt were obtained through the application of a structured questionnaire. Then, a total iodine knowledge score was calculated and grouped into low, medium and high knowledge categories. Urinary iodine concentration (UIC) was measured in spot urine samples by inductively coupled plasma MS. Of the pregnant women, 54 % correctly recognised iodine as important to neurocognitive development, 32 % were unable to identify any iodine-rich food and 71 % presented lack of knowledge regarding iodised salt. Of the women, 61 % had a medium total score of iodine knowledge. Knowledge on iodine importance during pregnancy was positively associated with iodine supplementation and also with UIC. Nevertheless, median UIC in women who correctly recognised the importance of iodine was below the cut-off for adequacy in pregnancy (150 µg/l). In conclusion, knowledge on iodine importance is positively associated with iodine status. Despite this, recognising iodine importance during pregnancy may not be sufficient to ensure iodine adequacy. Literacy-promoting actions are urgently needed to improve iodine status in pregnancy.

The association of milk and dairy consumption with iodine status in pregnant women in Oporto region

The role of milk and dairy products in supplying iodine to pregnant women is unknown in Portugal. The aim of this study was to evaluate the association between milk and dairy product consumption and the iodine status of pregnant women in the IoMum cohort of the Oporto region. Pregnant women were recruited between 10 and 13 weeks of gestation, when they provided a spot urine sample and information on lifestyle and intake of iodine-rich foods. Urinary iodine concentration (UIC) was determined by inductively coupled plasma MS. A total of 468 pregnant women (269 iodine supplement users and 199 non-supplement users) were considered eligible for analysis. Milk (but not yogurt or cheese) intake was positively associated with UIC, in the whole population (P = 0·02) and in the non-supplement users (P = 0·002), but not in the supplement users (P = 0·29). In non-supplement users, adjusted multinomial logistic regression analysis showed that milk consumption <3 times/month was associated with a five times increased risk of having UIC < 50 µg/l when compared with milk consumption ≥2 times/d (OR 5·4; 95 % CI 1·55, 18·78; P = 0·008). The highest UIC was observed in supplement users who reported consuming milk once per d (160 µg/l). Milk, but not yogurt or cheese, was positively associated with iodine status of pregnant women. Despite the observed positive association, daily milk consumption may not be sufficient to ensure adequate iodine intake in this population.

Prenatal and Postpartum Maternal Iodide Intake from Diet and Supplements, Urinary Iodine and Thyroid Hormone Concentrations in a Region of the United Kingdom with Mild-to-Moderate Iodine Deficiency

Iodine is essential for normal thyroid function, supporting healthy fetal and child development. Iodine requirements increase in pregnancy, but many women in regions without salt iodization have insufficient intakes. We explored associations between iodide intake and urinary iodine concentration (UIC), urinary iodine/creatinine ratio (I/Cr), thyroid stimulating hormone, thyroglobulin, free triiodothyronine, free thyroxine and palpable goiter in a region of mild-to-moderate iodine insufficiency. A total of 246 pregnant women aged 18–40 in Bradford, UK, joined the Health and Iodine in Babies (Hiba) study. They provided detailed information on diet and supplement use, urine and serum samples and were assessed for goiter at around 12, 26 and 36 weeks’ gestation, and 6, 18 and 30 weeks postpartum. Dietary iodide intake from food and drink was estimated using six 24 h recalls. During pregnancy, median (IQR) dietary iodide intake was 101 µg/day (54, 142), with 42% from dairy and 9% from white fish. Including supplements, intake was 143 µg/day (94, 196), with 49% < UK reference nutrient intake (140 µg/day). Women with Pakistani heritage had 129 µg/day (87, 190) median total intake. Total intake during pregnancy was associated with 4% (95% CI: 1%, 7%) higher UIC, 5% (3%, 7%) higher I/Cr, 4% (2%, 6%) lower thyroglobulin and 21% (9%, 32%) lower odds of palpable goiter per 50 µg/day. This cohort consumed less iodide in pregnancy than UK and World Health Organization dietary recommendations. UIC, I/Cr and thyroglobulin were associated with intake. Higher intake was associated with fewer goiters. Because dairy was the dominant source of iodide, women following plant-based or low-dairy diets may be at particular risk of iodine insufficiency.

MILK Symposium review: The importance of milk and dairy foods in the diets of infants, adolescents, pregnant women, adults, and the elderly

The ongoing increase in life expectancy is not always accompanied by an increase in healthy life span. There is increasing evidence that dietary exposure in early life can substantially affect chronic disease risk in later life. Milk and dairy foods are important suppliers of a range of key nutrients, with some being particularly important at certain life stages. It is now recognized that milk protein can stimulate insulin-like growth factor-1 (IGF-1), essential for longitudinal bone growth and bone mass acquisition in young children, thus reducing the risk of stunting. Low milk consumption during adolescence, particularly by girls, may contribute to suboptimal intake of calcium, magnesium, iodine, and other important nutrients. Given the generally low vitamin D status of European populations, this may have already affected bone development, and any resulting reduced bone strength may become a big issue when the populations are much older. Suboptimal iodine status of many young women has already been reported together with several observational studies showing an association between suboptimal iodine status during pregnancy and reduced cognitive development in the offspring. There is now good evidence that consumption of milk and dairy foods does not lead to an increased risk of cardiovascular diseases and type 2 diabetes. Indeed, some negative associations are seen, notably between yogurt consumption and type 2 diabetes, which should be researched with urgency. Greater emphasis should be placed on reducing malnutrition in the elderly and on dietary approaches to reduce their loss of muscle mass, muscle functionality, and bone strength. Whey protein has been shown to be particularly effective for reducing muscle loss; this needs to be developed to provide simple dietary regimens for the elderly to follow. There is an ongoing, often too simplistic debate about the relative value of animal versus plant food sources for protein in particular. It is important that judgments on the replacement of dairy products with those from plants also include the evidence on relative functionality, which is not expressed in simple nutrient content (e.g., hypotensive and muscle synthesis stimulation effects). Only by considering such functionality will a true comparison be achieved.

Iodine status of pregnant women with obesity from inner city populations in the United Kingdom

BACKGROUND/OBJECTIVES

Iodine is essential for foetal neurodevelopment and growth. Requirements increase in pregnancy to support increased thyroid hormone synthesis for maternal and foetal requirements, and for foetal transfer. Iodine deficiency in pregnancy is widely reported, and obesity has been associated with sub-optimal thyroid function. We evaluated iodine status and its relation with birthweight in a secondary analysis of pregnant women with obesity from multi-ethnic inner-city settings who participated in the UK Pregnancies Better Eating and Activity trial (UPBEAT).

SUBJECTS/METHODS

Iodine and creatinine concentrations were evaluated in spot urine samples in the second (15⁺⁰-18⁺⁶ weeks, n = 954) trimester of pregnancy. We assessed iodine status as urinary iodine concentration (UIC) and urinary iodine-to-creatinine ratio (UI/Cr) and applied WHO/UNICEF/IGN population threshold of median UIC > 150 µg/L for iodine sufficiency. Relationships between iodine status and birthweight were determined using linear and logistic regression with appropriate adjustment, including for maternal BMI and gestational age.

RESULTS

Median (IQR) UIC and UI/Cr in the second trimester of pregnancy were 147 µg/L (99-257) and 97 µg/g (59-165), respectively. An UI/Cr <150 μg/g was observed in 70% of women. Compared to women with UI/Cr >150 µg/g, there was a trend for women with UI/Cr <150 µg/g to deliver infants with a lower birthweight (β = -60.0 g; 95% CI -120.9 to -1.01, P = 0.05).

CONCLUSIONS

Iodine status of pregnant women with obesity from this cohort of UK women was suboptimal. Lower iodine status was associated with lower birthweight.

Is iodized salt efficient to overcome iodine deficiency in pregnants?

Objective:

Iodine is a trace element that synthesizes thyroid hormones necessary for optimal human growth and development. The relationship between dietary iodine intake and spot urinary iodine excretion in pregnant women has not been previously evaluated in Trabzon city, which is an endemic area of iodine deficiency in the Black Sea region of Turkey. This study aimed to evaluate the relationship between dietary iodine intake and urine iodine excretion in pregnant women.

Materials and Methods:

This study enrolled 150 pregnant women aged between 19 and 45 years who applied to Clinic of Gynecology and Obstetrics in Trabzon. Spot urine specimens were taken, and dietary iodine intake data were collected using a food frequency questionnaire (FFQ) and 24-hours dietary recall (24-h DR) method.

Results:

The median urinary iodine concentration (UIC) in the general specimen was 100.6 μg/L. Of the pregnant women, 80.0% had insufficient and 20.0% had sufficient iodine levels, according to UIC. Although total iodine-rich food intake determined by FFQ was sufficient in 20.7% (n=31) of participants, 24-h DR iodine intake was sufficient only 10.7% (n=16). A significant association between urinary iodine excretion and iodine intake was observed in both 24-h DR and FFQ intake estimates (p<0.05). The iodine intake values obtained in both 24-h DR and FFQ and the iodized salt effect were correlated with UIC in all models (p<0.05). Even though 96.0% of pregnant women used iodized salt, its effect on UIC was 15.2%.

Conclusion:

Both methods indicate that the iodine intake of pregnant women might be insufficient in Trabzon area. Also, although iodized salt use is high in pregnant women in Trabzon, it is not enough to prevent iodine deficiency.

Feed-derived iodine overrides environmental contribution to cow milk

Diets worldwide are deficient in iodine, leading to a range of undesirable health effects at the population level. Dairy products are a primary source of iodine in diets for those populations in which iodized salt is not systematically used or available. However, the flows of iodine through dairy agroecosystems are not well understood. The aim of this research was to investigate iodine flows though the dairy agroecosystem, including the influence of atmospheric depositional inputs, environmental variables, season, husbandry, and diet. Three farm-based sampling campaigns were carried out in this investigation, with milk, soil, silage, grass, and feed iodine determined by inductively coupled plasma mass spectroscopy, and nonparametric statistical analysis tests were conducted on data sets obtained. Natural iodine inputs into the environment are dominated by atmospheric deposition, which mainly from sea spray, and thus the location of farms relative to the coast and prevailing wind direction. Herbage and silage produced from grass-based systems strongly correlated with soil iodine, yet there was a strong disconnect between soil, forage, and feed and the milk that results. This was due to the levels of iodine in supplemental feeds being approximately 10-fold higher than those in forage-derived feeds. The practice of feed supplementation, accentuated by summer housing of cows, led to elevated milk iodine.

Maternal and neonatal outcomes and determinants of iodine deficiency in third trimester of pregnancy in an iodine sufficient area

BACKGROUND

Mild to moderate iodine deficiency in pregnant women may expose them to the increased risk of the development of goiter and thyroid disorder. There is a relationship between low maternal UIC (Urinary iodine concentration) in pregnancy and diminished placental weight and neonatal head circumference. The current study was an attempt to assess iodine nutritional status, its determinants and relationship with maternal and neonatal outcomes.

METHODS

In this population based cross-sectional study, which was conducted from April 2017 to September 2018, information was collected from 884 women of 20-45 years old who referred for periodic pregnancy visits. UIC was measured in random urine samples by applying a manual method which was based on the Sandell-Kolthoff technique. Information related to neonatal and maternal complications was collected from the individuals enrolled in the study through systematic follow-ups of the research team in each hospitals and the referral of trained midwives to the place of delivery and the retrieval of the case files.

RESULTS

The results showed that out of 884 participants 838 (94.8%) had a urinary iodine concentration of more than 150 micrograms/litre and 46 (5.2%) showed urinary iodine concentrations less than 150 micrograms/litre. The median (IQR) urinary iodine concentration in the third trimester was 176 (165-196) μg/l. According to the WHO criteria 46 of the participants (5.2%) had insufficient urinary iodine concentrations, 805 (91.06%) had adequate urinary iodine concentrations while 33 (3.73%) showed more than adequate levels. There were no participants with urinary iodine concentrations higher than 500 micrograms/litre. The main influencing factors on maternal iodine deficiency in this study were weight gain during pregnancy (Odds Ratio (OR) =0.88, 95% CI: 0.82-0.95), number of previous pregnancy (OR = 0.59, 95% CI: 0.39-0.89) the interval between the most recent pregnancies (OR = 0.78, 95% CI: 0.64-0.95), whether or not the pregnancy has been Planned (OR = 2.92, 95% CI: 1.29-6.58) and nutritional complement consumption (OR = 3.64, 95% CI: 1.44-9.1). The need for a neonatal intensive care unit (NICU) admission (OR = 4.64, 95% CI: 1.81-11.9) and preterm birth (OR = 3.29, 95% CI: 1.51-7.1) were significantly related with maternal iodine deficiency before delivery. Also there is no significant differences regarding the mean maternal urinary iodine concentration between the normal and different maternal complications groups (p = 0.47).

CONCLUSION

Iodine deficiency in pregnant women can be improved by appreciate planning for pregnancy, proper inter-pregnancy time interval (> 12 months to < 5 years), appropriate nutrition during pregnancy. Besides, controlling maternal urinary iodine concentrations is important to prevent neonatal complications such as preterm delivery and NICU admission.

Similarities and differences of dietary and other determinants of iodine status in pregnant women from three European birth cohorts

PURPOSE

As a component of thyroid hormones, adequate iodine intake is essential during pregnancy for fetal neurodevelopment. Across Europe, iodine deficiency is common in pregnancy, but data are lacking on the predictors of iodine status at this life stage. We, therefore, aimed to explore determinants of iodine status during pregnancy in three European populations of differing iodine status.

METHODS

Data were from 6566 pregnant women from three prospective population-based birth cohorts from the United Kingdom (ALSPAC, n = 2852), Spain (INMA, n = 1460), and The Netherlands (Generation R, n = 2254). Urinary iodine-to-creatinine ratio (UI/Creat, µg/g) was measured in spot-urine samples in pregnancy (≤ 18-weeks gestation). Maternal dietary intake, categorised by food groups (g/day), was estimated from food-frequency questionnaires (FFQs). Multivariable regression models used dietary variables (energy-adjusted) and maternal characteristics as predictors of iodine status.

RESULTS

Median UI/Creat in pregnant women of ALSPAC, INMA, and Generation R was 121, 151, and 210 µg/g, respectively. Maternal age was positively associated with UI/Creat in all cohorts (P < 0.001), while UI/Creat varied by ethnicity only in Generation R (P < 0.05). Of the dietary predictors, intake of milk and dairy products (per 100 g/day) was positively associated with UI/Creat in all cohorts [ALSPAC (B = 3.73, P < 0.0001); INMA (B = 6.92, P = 0.002); Generation R (B = 2.34, P = 0.001)]. Cohort-specific dietary determinants positively associated with UI/Creat included fish and shellfish in ALSPAC and INMA, and eggs and cereal/cereal products in Generation R.

CONCLUSIONS

The cohort-specific dietary determinants probably reflect not only dietary habits but iodine-fortification policies; hence, public-health interventions to improve iodine intake in pregnancy need to be country-specific.

Iodine status of 8 to 10 years old children within 20 years following compulsory salt iodization policy in Shanghai, China

BACKGROUND

In 1996, Shanghai implemented universal salt iodization and has became the last provincial unit in China to carry out this intervention. In this study, we summarized achievements in past 20 years, to provide suggestions and evidence for the next stage of iodine supplementation.

METHODS

This study summarized and analyzed monitoring data of children from 1997, 1999, 2005, 2011, 2014, and 2017 in Shanghai. In each monitoring year, 30 streets or towns were selected using the probability-proportional-to-size sampling technique. One primary school was selected from each street or town by a simple random sampling technique. From each school, 40 children aged 8 to 10 years were randomly selected. The number of children was divided equally by sex and age.

RESULTS

In 1997, 1999, 2005, 2011, 2014, and 2017, median urinary iodine (MUI) was 227.5 μg/L, 214.3 μg/L, 198.1 μg/L, 181.6 μg/L, 171.4 μg/L, and 183.0 μg/L, goiter rate was 3.07, 0.40, 0.08, 0.08, 0.86, and 1.90%, and median thyroid volume (MTvol) was 2.9 mL, 1.2 mL, 2.4 mL, 1.0 mL, 1.8 mL, and 2.8 mL, respectively. There was a linear correlation between goiter rate and median thyroid volume (MTvol) (r = 0.95, P = 0.014). Household salt iodine concentration (SIC) was dropping every monitoring (P < 0.05). There was a significant difference among different household SIC groups in MUI in 1999 and 2017, and in MTvol in 1999 (P < 0.05). No significant differences were detected in the other years.

CONCLUSIONS

In Shanghai, the iodine status of 8 to 10 years old children is adequate. Household SIC have little effect on iodine status of children. Future studies should analyze the dietary sources of iodine, especially from pre-packaged and prepared-away-from-home foods or meals. The regular monitoring of iodine status is important to human health.

Iodine deficiency among pregnant women living in Northern Ireland

OBJECTIVE

Mild iodine deficiency has re-emerged among school girls in the UK. We wished to study a contemporaneous pregnant population because a relationship between maternal iodine deficiency and offspring cognitive scores has recently been reported. The WHO has set a median population urinary iodine concentration (UIC) of ≥100 and ≥150 µg/L to define adequacy outside of and during pregnancy, respectively. Iodine creatinine ratio (ICR) is also used to correct for dilution effects (sufficiency ≥150 µg/g creatinine in pregnancy).

DESIGN AND METHODS

A total of 241 women were followed across trimesters (T) into the postpartum period (PPP) along with 80 offspring with spot urine sampling and food frequency questionnaires.

RESULTS

Median UIC was 73 µg/L in the 1st T (ICR 102 µg/g creatinine) despite 55% taking iodine-containing supplements. Median UICs were 94, 117 and 90 µg/L in the 2nd T, 3rd T and PPP, respectively. Corresponding ICRs were 120, 126 and 60 µg/g creatinine. ICR was associated with volume of milk consumed throughout pregnancy. Median UIC among the offspring was 148 µg/L, with no difference between the breast- and formula-fed babies.

CONCLUSIONS

Pregnant women living in Northern Ireland may be at risk of iodine deficiency across pregnancy and into the PPP while the offspring are iodine sufficient. This is the first study of its kind in the UK with data for pregnant women and their offspring. The UK does not provide an iodine fortification programme nor offer routine iodine dietary advice in pregnancy and this requires consideration by public health agencies.

What is the availability of iodised salt in supermarkets on the Island of Ireland?

Iodine deficiency remains a global nutritional public health challenge, with evidence suggesting borderline adequate or even deficient status for UK and Irish subpopulations such as schoolgirls and pregnant women. The solution, according to the WHO, is salt iodisation, but it is not known how widely available iodised salt is in supermarkets. Iodised salt availability was determined by a shelf survey of 89 supermarket stores on the island of Ireland (n = 30 in Northern Ireland and n = 59 in the Republic of Ireland) from September 2018 to January 2019, to take into account factors such as store type, location, population density, socioeconomic status and ethnicity. Availability was calculated as the number of stores selling iodised salt as a percentage of the total. Iodised salt was only available in 11 stores (12%), of which 10 were ethnic stores. This indicates a lack of access for the majority of the Irish and Northern Irish populations.

[Factors associated with the nutritional status of iodine in the maternal-infant group: a systematic review]

This article sets out to identify the socio-demographic and nutritional factors associated with the nutritional status of iodine in the maternal-infant group. The review was based on the Prisma method and the Medline (PubMed), Scopus and Lilacs databases were consulted. The search was conducted in December 2018, using the key words nutritional status, iodine, infant, pregnant and lactating. The selection followed the stages of excluding duplicated articles, reading the titles, abstracts and texts in full. A total of 1,500 studies were identified and 26 met the inclusion criteria. The methodological quality of the studies was evaluated using the questionnaire proposed by Downs and Black. There was an association between the sociodemographic factors of income, education, maternal and gestational age, uniformity and place of residence in rural or urban areas with the nutritional state of iodine. In relation to dietary factors, the consumption of supplements, iodized salt and dietary sources of iodine, especially dairy products, play a protective role to avoid the deficiency. It is necessary to create more specific and effective strategies that address all the factors that affect the nutritional state of iodine to avoid the disorders resulting from the deficiency.

Maternal Iodine Status and Associations with Birth Outcomes in Three Major Cities in the United Kingdom

Severe iodine deficiency in mothers is known to impair foetal development. Pregnant women in the UK may be iodine insufficient, but recent assessments of iodine status are limited. This study assessed maternal urinary iodine concentrations (UIC) and birth outcomes in three UK cities. Spot urines were collected from 541 women in London, Manchester and Leeds from 2004–2008 as part of the Screening for Pregnancy End points (SCOPE) study. UIC at 15 and 20 weeks’ gestation was estimated using inductively coupled plasma-mass spectrometry (ICP-MS). Associations were estimated between iodine status (UIC and iodine-to-creatinine ratio) and birth weight, birth weight centile (primary outcome), small for gestational age (SGA) and spontaneous preterm birth. Median UIC was highest in Manchester (139 μg/L, 95% confidence intervals (CI): 126, 158) and London (130 μg/L, 95% CI: 114, 177) and lowest in Leeds (116 μg/L, 95% CI: 99, 135), but the proportion with UIC <50 µg/L was <20% in all three cities. No evidence of an association was observed between UIC and birth weight centile (−0.2% per 50 μg/L increase in UIC, 95% CI: −1.3, 0.8), nor with odds of spontaneous preterm birth (odds ratio = 1.00, 95% CI: 0.84, 1.20). Given the finding of iodine concentrations being insufficient according to World Health Organization (WHO) guidelines amongst pregnant women across all three cities, further studies may be needed to explore implications for maternal thyroid function and longer-term child health outcomes.

A Comparative Study of Iodized Salt Programs: Shanghai and Switzerland

Both Shanghai and Switzerland are developed regions with long-standing salt iodization programs and periodic monitoring. However, the two regions have their own approach to the implementation of the iodized salt policy. In Shanghai, monitoring was carried out every few years, using probability-proportional-to-size sampling technique to select 30 sampling units. Each unit consisted of more than 12 pregnant women and one randomly selected primary school. Urine samples were then taken from the chosen pregnant women and randomly recruited students of that school for iodine test. Data of Switzerland used in this comparative study was extracted from published researches. In Shanghai, the median urinary iodine concentration (UIC) in 2014 was 20% lower than in 1999 (P < 0.05). The median UIC of pregnant women in 2014 was 9.5% lower than that in 2011 (P < 0.05). In terms of iodized salt concentration, opposite to the increasing in Switzerland, it has exhibited a downward trend in Shanghai (P < 0.05). For the years monitored, the iodized salt concentration in Shanghai was significantly (P < 0.05) higher than in Switzerland. Though the UIC of children exhibited a downward trend in Shanghai (P < 0.05), it was still significantly (P < 0.05) higher than in Switzerland over the same monitoring period. However, the UIC in pregnant women was a totally different story, which was significantly (P < 0.05) lower in Shanghai than in Switzerland. Iodized salt is very important for maintaining sufficient iodine level in the population. Appropriate concentration of iodine in fortified salt needs to be decided according to local conditions. Special attention should be paid to the iodine level of pregnant women in Shanghai, and more education about iodine is necessary for the public health.

A systematic review of iodine deficiency among women in the UK

OBJECTIVE

The present study reviewed the literature on iodine status among women of childbearing age and pregnant women in the UK. Particular attention was given to study quality and methods used to assess iodine status.

DESIGN

A systematic review was conducted to examine the literature and critically evaluate study design.

SETTING

Studies were identified in PubMed, Web of Science, Scopus and Ovid MEDLINE databases, as well as from secondary references.

PARTICIPANTS

Women of childbearing age or pregnant, living in the UK.

RESULTS

Fifty-seven articles were identified and twelve articles were selected, including a total of 5283 women. Nine studies conducted urinary iodine assessments, three studies conducted dietary assessments only, and seven studies classified their target population as iodine deficient according to WHO criteria.

CONCLUSIONS

No single study from the selected articles could produce nationally representative results regarding the prevalence of iodine deficiency among the female population in the UK. Consideration of the evidence as a whole suggests that women of childbearing age and pregnant women in the UK are generally iodine insufficient. Further large-scale research is required for more accurate and reliable evidence on iodine status in the UK.

A Comparison of Iodine Status in Children and Pregnant Women After a Policy Change in the Iodized Salt Standard in Shanghai, China

In Shanghai, a new iodized salt standard was implemented in 2012. To provide evidence to the government, we compared iodine status before (35 mg/kg) and after (30 mg/kg) adjustment in vulnerable populations living in Shanghai. The probability-proportional-to-size sampling technique was used to select at least 360 pregnant women for urine iodine test and at least 1200 students for thyroid measurement and the household salt test. Of these students, at least 360 performed urine iodine test. The median thyroid volume and the median household salt iodine concentration of children aged 8-10 years were 1.80 ml and 24.8 mg/kg in 2015, and 0.97 ml and 28.3 mg/kg in 2011. The median urine iodine concentration (UIC) of pregnant women was 126.52 and 139.77 μg/L in 2015 and 2011. All differences were statistically significant (P < 0.05). The median UIC of students was 171.40 and 181.63 μg/L in 2015 and 2011, the difference was not statistically significant. Multivariate linear regression analysis showed that thyroid volume in children was associated with sex, age, region, and household salt iodized concentration. The current iodized salt concentration meets the basic needs of the population's iodine requirements except for pregnant women. Periodic monitoring is necessary particularly in vulnerable groups.

Maternal marginal iodine deficiency delays cerebellar Bergmann glial cell development in rat offspring: Involvement of Notch signaling pathway

During early pregnancy, iodine deficiency (ID) is linked to adverse effects on child motor and psychomotor function. Maternal marginal ID has become a common public health problem. It is unclear whether marginal ID influences the development of the cerebellum or its underlying mechanisms. Thus, the purpose of this study was to determine the effects of marginal ID on the development of cerebellar Bergmann glial cells (BGs) and investigate the activation of the Notch signaling pathway, which is crucial for the development and morphology of BGs. We treated Wistar rats with an ID diet (iodine content 60 ± 1.5 ng/g) supplemented with deionized water containing different concentrations of potassium iodide (KI) (183, 117, and 0 μg/L for the control, marginal ID, and severe ID groups, respectively) during pregnancy and lactation. We explored the morphology of the BGs by Golgi-Cox staining and immunofluorescence and investigated the Notch signaling pathway using western blot. Our results showed that the marginal ID and severe ID groups had decreased cerebellar BG fiber lengths (P < 0.05 and 0.01, respectively) and numbers (P < 0.01 for both) on postnatal day (PN) 7, PN14, and PN21 compared to the control group. Moreover, the data showed that severe ID significantly reduced Dll1, Notch1, RBP-Jκ, and BLBP protein levels at all three time points. Marginal ID slightly reduced the expression of Notch1 on PN7 (P < 0.05) and PN21 (P < 0.01), RBP-Jκ on PN14 (P < 0.01) and PN21 (P < 0.05), and BLBP on PN7 (P < 0.05). There was no significant difference in Dll1 protein levels between the marginal ID and control groups at any time point. Our study suggests that marginal ID leads to mild damage to BG morphogenesis in the cerebellum. The abnormal regulation of the Notch signaling pathway may be involved in the damage to BGs.

Preconception Maternal Iodine Status Is Positively Associated with IQ but Not with Measures of Executive Function in Childhood

Background

Adverse effects of severe maternal iodine deficiency in pregnancy on fetal brain development are well-established, but the effects of milder deficiency are uncertain. Most studies examine iodine status in pregnancy; less is known about iodine nutrition before conception.

Objective

We examined relations between maternal preconception iodine status and offspring cognitive function, within a prospective mother-offspring cohort.

Methods

Maternal iodine status was assessed through the use of the ratio of iodine:creatinine concentrations (I/Cr) in spot urine samples [median (IQR) period before conception 3.3 y (2.2-4.7 y)]. Childhood cognitive function was assessed at age 6-7 y. Full-scale IQ was assessed via the Wechsler Abbreviated Scale of Intelligence, and executive function through the use of tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB). Analyses (n = 654 mother-child dyads) were adjusted for potential confounders including maternal intelligence, education, and breastfeeding duration.

Results

The median (IQR) urinary iodine concentration was 108.4 µg/L (62.2-167.8 µg/L) and the I/Cr ratio 114 µg/g (76-164 µg/g). The preconception I/Cr ratio was positively associated with child IQ, before and after adjustment for potential confounding influences [β = 0.13 (95% CI: 0.04, 0.21)/SD, P = 0.003]. 8.9% of women had a preconception urinary I/Cr ratio <50 µg/g; compared with those with an I/Cr ratio ≥150 µg/g, the IQ of their offspring was 0.49 (95% CI: 0.79, 0.18) SD lower. There were no associations with the executive function outcomes assessed via CANTAB, before or after adjustment for confounders.

Conclusion

The positive association between iodine status before conception and child IQ provides some support for demonstrated links between low maternal iodine status in pregnancy and poorer cognitive function reported in other studies. However, given the negative effects on school performance previously observed in children born to iodine-deficient mothers, the lack of associations with measures of executive function in the present study was unexpected. Further data are needed to establish the public health importance of low preconception iodine status.

Urinary iodine concentration and thyroid volume of pregnant women attending antenatal care in two selected hospitals in Ashanti Region, Ghana: a comparative cross-sectional study

BACKGROUND

Iodine deficiency is a major public health problem affecting people worldwide, particularly pregnant women. Iodine requirements increase substantially during pregnancy making pregnant women vulnerable to iodine deficiency and its disorders such as abortions, stillbirths and pregnancy goitre as well as congenital abnormalities, cretinism and mental retardation in their children. The primary aim of this study was to evaluate the prevalence of iodine deficiency and goitre among pregnant women attending antenatal sessions at two selected hospitals in Ashanti region, Ghana.

METHODS

A cross-sectional study was carried out in 239 pregnant women who attended the antenatal clinic at Kwame Nkrumah University of Science and Technology (KNUST) Hospital or Ejura District Hospital, both in Ashanti Region, Ghana. Socio-demographic data and information related to iodine were captured using a questionnaire. Urinary iodine concentration (UIC) was determined on spot urine samples using the Sandell-Kolthoff reaction with ammonium persulfate as digesting agent. Each woman's thyroid volume was also measured by ultrasonography.

RESULTS

The overall median UIC was 155.9 μg/L, indicating adequate iodine intake in the study population. However, goitre prevalence in the pregnant women was 11.3%, denoting mild iodine deficiency. The median UIC for pregnant women who attended KNUST Hospital was higher (163.8 μg/L) than that of Ejura District Hospital (149.0 μg/L). The proportion of women who did not consume iodised salt was significantly higher (p < 0.001) in Ejura District Hospital (71.2%) than KNUST Hospital (28.0%). In total, 47.3% of the pregnant women studied had a UIC < 150 μg/L. Only 16.3% knew about the increase in iodine requirement during pregnancy and 21.3% of them had knowledge of the effects of iodine deficiency during pregnancy with most (81.8%) knowing of pregnancy goitre.

CONCLUSION

There is generally adequate iodine intake among the pregnant women, however, iodine deficiency and goitre still exist among some pregnant women. Thus, assessment and continuous monitoring of iodine nutritional status in pregnant women in the country are warranted. Also, intensification of effective public health campaigns (through radio and television) with regard to iodine utilization and its benefits in pregnancy are still recommended among Ghanaian pregnant women.

A review of guidance on fish consumption in pregnancy: is it fit for purpose?

OBJECTIVE

Public health messages to reduce Hg exposure for pregnant women have focused exclusively on advice on fish consumption to limit Hg exposure, with little account being taken of the positive contribution of fish to nutritional quality. The aim of the present review was to compare and contrast the content and presentation of national guidelines on fish consumption in pregnancy, and comment on their evidence base and impact on consumption.

DESIGN

We searched for national and international guidelines on fish consumption in pregnancy using Internet search strategies. The detailed content and style of presentation of the guidelines were compared. The evidence base for the guidelines, and evidence for the impact of the guidelines on fish consumption levels, were assessed.

RESULTS

We identified nineteen national guidelines and three international guidelines. There was great variation in the content, complexity and presentation style. The guidelines were based largely on the Hg content of fish with far less consideration being given to the positive beneficial effects of nutrients provided by fish. The complexity of the guidelines may lead to pregnant women reducing their fish intake, or not eating fish at all.

CONCLUSIONS

Guidelines on fish consumption in pregnancy should take the beneficial effects of fish into account. Guidelines need to be clear and memorable, and appropriately disseminated, to achieve impact. Guidelines could include visual rather than narrative content. Use of technology, for example apps, could enable women to record their fish consumption in real time and log compliance with guidance over a week or other time period.

Iodine Status during Pregnancy in a Region of Mild-to-Moderate Iodine Deficiency is not Associated with Adverse Obstetric Outcomes; Results from the Avon Longitudinal Study of Parents and Children (ALSPAC)

Severe iodine deficiency during pregnancy has been associated with pregnancy/neonatal loss, and adverse pregnancy outcomes; however, the impact of mild–to–moderate iodine insufficiency, though prevalent in pregnancy, is not well-documented. We assessed whether mild iodine deficiency during pregnancy was associated with pregnancy/infant loss, or with other adverse pregnancy outcomes. We used samples and data from the Avon Longitudinal Study of Parents and Children (ALSPAC), from 3140 singleton pregnancies and from a further 42 women with pregnancy/infant loss. The group was classified as mildly-to-moderately iodine deficient with a median urinary iodine concentration of 95.3 µg/L (IQR 57.0–153.0; median urinary iodine-to-creatinine ratio (UI/Creat) 124 µg/g, IQR 82–198). The likelihood of pregnancy/infant loss was not different across four UI/Creat groups (<50, 50–149, 150–250, >250 µg/g). The incidence of pre-eclampsia, non-proteinuric gestational hypertension, gestational diabetes, glycosuria, anaemia, post-partum haemorrhage, preterm delivery, mode of delivery, being small for gestational age, and large for gestational age did not differ significantly among UI/Creat groups, nor were there any significant differences in the median UI/Creat. We conclude that maternal iodine status was not associated with adverse pregnancy outcomes in a mildly-to-moderately iodine-deficient pregnant population. However, in view of the low number of women with pregnancy/infant loss in our study, further research is required.