Excess Iodine Research Articles

Biogeochemical cycling of Cd, Mn, and Ce in the Eastern Tropical North Pacific oxygen‐deficient zone

AbstractOxygen‐deficient zones (ODZs) play an important role in the distribution and cycling of trace metals in the ocean, as important sources of metals including Fe and Mn, and also as possible sinks of chalcophile elements such as Cd. The Eastern Tropical North Pacific (ETNP) ODZ is one of the three largest ODZs worldwide. Here, we present results from two sectional surveys through the ETNP ODZ conducted in 2018, providing high‐resolution concentrations of several metals, along with complimentary measurements of nutrients and iodine speciation. We show that samples obtained from the ship's regular rosette are clean for Cd, Mn, Ni, and light rare earth elements, while uncontaminated Fe, Zn, Cu, and Pb samples cannot be obtained without a special trace‐metal clean sampling system. Our results did not show evidence of Cd sulfide precipitation, even within the most oxygen‐depleted water mass. High Mn and Ce concentrations and high Ce anomalies were observed in low‐oxygen seawater. These maxima were most pronounced in the upper water column below the oxycline, coincident with the secondary nitrite maxima and the lowest oxygen concentrations, in what is generally considered the most microbially active part of the water column. High Mn and Ce features were also coincident with maxima in excess iodine, a tracer of shelf sediment sources. Mn and Ce maxima were most prominent within the 13°C water mass, spanning a density horizon that enhances isopycnal transport from the shelf sediments, resulting in transport of Mn and Ce at least 2500 km offshore.

Residual effect of biofortified iodine in soil, plant, crop yield and quality of tomato (Solanum lycopersicum L.)

When iodine levels in the soil are inadequate, resulting in limited crop uptake and as a result, a population with insufficient iodine intake. Iodine deficiency can be avoided by biofortifying commonly consumed crops with iodine. Tomato is the best crop for biofortification study as it is having the capacity to store excess iodine in pholoem. The field experiment was carried out in Thondamuthur block of Viraliyur village at Coimbatore district of Tamil Nadu in 2021. The purpose of this study was to determine the effect of biofortication of iodine in residual tomato growth, yield, quality and iodine content. Potassium iodate and Chitosan were applied in the form of soil, foliar and Chitosan iodate complex at different stages of plant growth. The results revealed that the soil fertilization of potassium iodate alone resulted in lower uptake of residual iodine in fruits because the iodine was susceptible to high volatilization and less phyto-availability. While foliar spray alone increased the residual iodine content in roots and stem. However, residual higher iodine accumulation in the tomato fruits was achieved through the combination of foliar and iodine Chitosan forms. As electrostatic interaction between Chitosan and iodate prevents volatilization and gradually increases the bioavailability of iodine from soil to fruits. Based on the discussion, biofortification of iodine through potassium iodate Chitosan complex paved the way for the improvement of growth, yield, quality and iodine content in fruits. Hence, biofortification of iodine through iodate Chitosan complex increased the iodine content in tomato fruit and introducing it in our daily diet may be helpful to reduce iodine deficiency disorder.

Protection of Vitamin C on Oxidative Damage Caused by Long-Term Excess Iodine Exposure in Wistar Rats.

Vitamin C was reported to be able to protect against oxidative damage due to its reducibility. 120 Wistar rats were randomly divided into 4 × 2 groups, including normal iodine (NI), high iodine (HI), low vitamin C (HI + LC), and high vitamin C (HI + HC); potassium iodide (KI) and potassium iodate (KIO3) were commonly used as additives for iodized salt, so every group was also divided into KI and KIO3 groups. After 6 months' feed, the activities of antioxidant enzymes and Lipid Peroxide (MDA) content in serum, liver, kidney, brain, thyroid and lens were determined. In serum, for males, long-term excess iodine intake caused oxidative damage; in the liver, male rats in the HI + LC group had the highest MDA content, which showed that low-dose vitamin C might promote oxidative damage; in kidneys, the MDA content in the HI and HI + LC groups of females was higher; in the brain, high-dose vitamin C could increase the activity of superoxide dismutase (SOD), which was decreased by high iodine intake, and it also decreased MDA content; in the thyroid, for KIO3, the activity of SOD in the HI group was lower than NI and HI + LC; in the lens, the MDA content in females was lower than males. Long-term excess iodine exposure caused oxidative damage and showed sex difference, and vitamin C had a protective effect on it, especially for high-dose vitamin C.

Excess iodine exposure acutely increases salivary iodide and antimicrobial hypoiodous acid concentrations in humans

The lactoperoxidase (LPO)-hydrogen peroxide-halides reaction (LPO system) converts iodide and thiocyanate (SCN−) into hypoiodous acid (HOI) and hypothiocyanite (OSCN−), respectively. Since this system has been implicated in defense of the airways and oropharynx from microbial invasion, in this proof-of-concept study we measured the concentrations of these analytes in human saliva from a convenience clinical sample of 40 qualifying subjects before and after acute iodine administration via the iodinated contrast medium used in coronary angiography to test the hypothesis that an iodide load increases salivary iodide and HOI concentrations. Saliva was collected and salivary iodide, SCN−, HOI and OSCN− were measured using standard methodology. The large iodine load delivered by the angiographic dye, several 100-fold in excess of the U.S. Recommended Daily Allowance for iodine (150 µg/day), significantly increased salivary iodide and HOI levels compared with baseline levels, whereas there was no significant change in salivary SCN− and OSCN− levels. Iodine load and changes of salivary iodide and HOI levels were positively correlated, suggesting that higher iodide in the circulation increases iodide output and salivary HOI production. This first of its kind study suggests that a sufficient but safe iodide supplementation less than the Tolerable Upper Limit for iodine set by the U.S. Institute of Medicine (1,100 µg/day) may augment the generation of antimicrobial HOI by the salivary LPO system in concentrations sufficient to at least in theory protect the host against susceptible airborne microbial pathogens, including enveloped viruses such as coronaviruses and influenza viruses.

Deficiency and excess of groundwater iodine and their health associations

More than two billion people worldwide have suffered thyroid disorders from either iodine deficiency or excess. By creating the national map of groundwater iodine throughout China, we reveal the spatial responses of diverse health risks to iodine in continental groundwater. Greater non-carcinogenic risks relevant to lower iodine more likely occur in the areas of higher altitude, while those associated with high groundwater iodine are concentrated in the areas suffered from transgressions enhanced by land over-use and intensive anthropogenic overexploitation. The potential roles of groundwater iodine species are also explored: iodide might be associated with subclinical hypothyroidism particularly in higher iodine regions, whereas iodate impacts on thyroid risks in presence of universal salt iodization exhibit high uncertainties in lower iodine regions. This implies that accurate iodine supply depending on spatial heterogeneity and dietary iodine structure optimization are highly needed to mitigate thyroid risks in iodine-deficient and -excess areas globally.

Salt Production and Availability of Iodized Salt in the Municipality of Sèmè-Kpodji in 2022

Background: Cooking salt is widely used to provide iodine to humans. In Benin, the production of salt is still artisanal. Our study focused on salt produced in Sèmè-Kpodji, a secondary site of local salt production in Benin, and on the availability of iodine in salt in this municipality. Methods: The descriptive cross-sectional study included exhaustive salt producers and randomly selected households in Sèmè-Kpodji. Direct observation was made to describe salt production. In household, a standard questionnaire collected data about the physical characteristic of salt used. Iodine content was determined with the MBI kit and by the iodometric titration method. Results: A total of 8 producers and 365 participants in the households were surveyed. Salt is produced by drying sea water on tarps for three and a half days. The process is done in eight (8) steps, the last of which is the iodization of the product and the packaging. By iodometric titration, the salt produced had an iodine content of 5.2ppm. The mean content of iodine in salt in household was: 87.5 ± 66.0ppm (2.6-396.1). Only 31.2% of cooking salt samples were adequately iodized (15-40ppm). High iodine concentrations have been observed in 62.2% of salt samples. Conclusion: Salts consumed in households in Sèmè-Kpodji ’municipality were, for the most part, excessively iodized, whereas local production is artisanal and low in iodine. Iodization of the latter is mandatory before marketing. A monitoring of the salt iodization strategy should be maintained to avoid excessive iodine consumption which can cause hormonal disorders.

PSAT322 A "Natural Thyroid Booster" Induced Hyperthyroidism

Abstract Background In the recent years market got filled with a variety of freely available and not FDA regulated supplements that claim to ensure thyroid gland "support", "activation", "boost", "restoration", "drive", "edge", "strength" and a midst of other positive effects. These supplements are often not considered as medications and often are not reported during medication reconciliation. We present a case of hyperthyroidism in a patient using a supplement containing potassium iodide Clinical Case 54-year-old male with newly diagnosed atrial fibrillation in Feb 2021 presented in September 2021 with non-ST elevation myocardial infarction. He continued to have persistent atrial fibrillation. At presentation TSH was nearly suppressed at 0.02 MIU/ml, FT4 was normal at 1.6 ng/dl, TT3 increased at 241 ng/dL. During endocrinology evaluation in October 2021 thyroid function values remained the same, TSI and TRAB were negative and TGAB were increased at 8 IU/ml. Imaging studies were not consistent with thyroiditis (heterogenous and hypervascular gland on ultrasound, normal RAI), a possibility of antibody negative Graves’ disease was entertained, however thyroid function tests in November 2021 were quite different and showed elevated TSH of 71 MIU/L, FT4 low at 0.3 ng/dl, low TT3 at 48 ng/dl. At this time patient recalled being on thyroid supplement in the recent past, per patient he did not realize that it was relevant information to disclose to the physician. He was on "Thyroid PX" from September 2020 to February 2021 per recommendation from naturopathic doctor for symptomatic subclinical hypothyroidism when in September 2020 TSH was noticed to be mildly elevated at 6.73 MIU/ml, FT4 normal at 1. 0 ng/dl and TT3 normal at 99 ng/dl. Conclusion This case represents an example of thyroid supplement use related thyrotoxicosis. He was taking "megadoses" (80 times the recommended daily dose) of iodine that likely have caused Jod-Basedow phenomenon, which is a hyperthyroidism following exposure to the excess of iodine. Among documented ingredients of "Thyroid PX" are potassium iodide, cholecalciferol, methylcobalamim, Ashwagandha root, Ginger root, Nettle leaf and others. Each capsule contains 6000mcg of Potassium Iodide (daily dose – 2 capsules) with recommended daily iodine dose for adults of 150mcg. Hyperthyroid stage was followed by the stage of profound hypothyroidism. The patient could have been predisposed to Jod-Basedow phenomenon due to Hashimoto thyroiditis. This illustrates an importance of obtaining detailed history of use of any/thyroid supplements in all patients with unexplained hyperthyroidism. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

PSAT330 Excess Iodine Intake From a Cystic Fibrosis Supplement Induces Symptomatic Hypothyroidism

Abstract A 45-year-old woman with cystic fibrosis (delF508/delF508), pancreatic exocrine insufficiency, and diet-controlled cystic fibrosis-related diabetes presented with new complaints of dry skin, hair loss, and cold intolerance. She had no personal or family history of thyroid disease. Physical exam was notable for a mildly enlarged, non-tender thyroid gland without nodules, and 2+ bicep reflexes with delayed relaxation phase. Labs revealed a TSH of 17 mcIU/mL (n 0.3-4.20 mcIU/mL), free T4 of 0.6 ng/dL (n 0.9-1.7 ng/dL), and a thyroid peroxidase antibody of 15 units/mL (n 0-34 units/mL), consistent with new onset, overt hypothyroidism. Thyroid ultrasound revealed a hypervascular, heterogeneous gland, suggestive of underlying autoimmune thyroid disease. Given such an abrupt and significant change in previously normal thyroid studies, further history was obtained. The patient disclosed taking TauriNac, a supplement discovered online that is believed to help clear heavy metals, which she believed she was exposed to via IV antibiotics, and for treatment of her cystic fibrosis. The patient was taking 3-4 packets of TauriNac per day, totaling 16,000 mcg of potassium iodide, far exceeding the Recommended Dietary Allowance of 150 mcg per day. She discontinued TauriNac and one month later, thyroid function tests normalized. The patient then resumed TauriNac, 2-3 packets per day, and within five months TSH rose to 9.66 mcIU/mL with free T4 0.9 ng/dL. She again stopped taking TauriNac and two months after discontinuation thyroid levels normalized. Later, after yet again resuming TauriNac, 5 packets per week, her TSH increased to 4.71 mcIU/mL. She subsequently discontinued TauriNac with normalization of her TSH after three months. Over one year later, she remains off TauriNac and is clinically and biochemically euthyroid. In the 1970s, development of a goiter and hypothyroidism was reported in CF patients, especially those treated with iodine-based expectorants, raising concern for underlying thyroid dysfunction in CF; however the true prevalence of underlying thyroid dysfunction in CF patients is controversial. A 2016 United States-based study of CF patients revealed abnormal thyroid function tests in 27%, however the abnormalities were mild, and overt thyroid dysfunction was rare. In our center's experience, transient subclinical hypothyroidism associated with CF exacerbations is common and may correlate with poor dietary intake leading to iodine deficiency. In this case, excessive iodide intake via TauriNAC clearly correlated with the development of symptomatic hypothyroidism, presumably due to failure to escape the Wolff-Chaikoff effect. In a 2002 survey of adult CF patients, 70% reported having taken complementary and alternative medicine (CAM) in the past. The high prevalence of CAM use in the CF population as well as prior studies demonstrating iodine induced hypothyroidism in CF patients should inform providers of the potential harmful effects of iodine supplementation in an iodine-replete population. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

The relationship between urinary iodine concentration and papillary thyroid cancer: A systematic review and meta-analysis.

The effect of iodine on papillary thyroid cancer (PTC) has been controversial for many years. Since urinary iodine is an effective indicator of iodine intake, some recent epidemiological studies have described the relationship between urinary iodine concentration (UIC) and PTC. We searched PubMed, Embase, Cochrane Library, and Web of Science for case-control studies about UIC and PTC published before September 2022. Results are presented as the overall odds ratio (OR) and 95% confidence intervals (CI). According to the analysis of the included studies, excessive iodine intake (UIC≥300ug/L) was positively associated with the occurrence of PTC patients compared with healthy controls (OR4.05, 95%CI 1.64-10.02, P=0.002). Meanwhile, adequate iodine exposure (100≤UIC<200ug/L) may play a protective role in the occurrence of PTC compared with healthy individuals (OR 0.36, 95%CI 0.14-0.91, P=0.03) while the difference in the prevalence of insufficient iodine intake (UIC<100ug/L) and iodine above requirements (200≤UIC<300ug/L) among the two groups were not significant (deficiency: OR 0.38, 95%CI 0.13-1.16, P=0.09; above requirements: OR 0.92, 95%CI 0.40-2.10, P=0.84). After comparing the UIC levels of PTC patients with those of other thyroid diseases, we found that there was also no significant difference in the incidence of different levels of UIC in the two groups (excessive: OR 1.25, 95%CI 0.87-1.80, P=0.22; above requirements: OR 0.93, 95%CI 0.77-1.14, P=0.49; adequate: OR 0.96, 95%CI 0.78-1.17, P=0.67; deficiency: OR 1.02, 95%CI 0.86-1.22, P=0.80). The result of this meta-analysis also did not support the relationship between UIC and the BRAF mutation and lymph node metastasis (LNM) of PTC patients. Besides, we also found that studies on the relationship between urinary iodine and PTC may be influenced by the way UIC was measured. The 10 case-control included studies involved a total of 6,544 participants. The results of this meta-analysis showed excessive iodine intake, that is, UIC≥300ug/L was associated with the occurrence of PTC but not with BRAF mutation and LNM while adequate iodine intake (100≤UIC<200ug/L) may be one of the protective factors for PTC.

The Interactive Effects of Severe Vitamin D Deficiency and Iodine Nutrition Status on the Risk of Thyroid Disorder in Pregnant Women.

Thyroid dysfunction is associated with both vitamin D deficiency and iodine; however, it is unclear whether they interact. This study aimed to investigate whether and to what extent the interactions between vitamin D and iodine contribute to the risk of thyroid disorder. Participants (n = 4280) were chosen using multistage, stratified random sampling from Shanghai. Fasting blood was drawn for the 25(OH)D and thyroid parameter tests. Spot urine samples were gathered to test for urine iodine. To evaluate the interactive effects of vitamin D and iodine, crossover analysis was carried out. Pregnant women with a high urinary iodine concentration (UIC) and severe vitamin D deficiency had a significantly higher risk of thyrotropin receptor antibody (TrAb) positivity (odds ratio = 2.62, 95% confidence interval (CI): 1.32, 5.22) in the first trimester. Severe vitamin D deficiency and high UIC interacted positively for the risk of TrAb positivity (relative excess risk due to interaction = 1.910, 95%CI: 0.054, 3.766; attributable proportion = 0.700, 95%CI: 0.367, 1.03). Severe vitamin D deficiency combined with excess iodine could increase the risk of TrAb positivity in pregnant women in the first trimester.

Anion···Anion [AuI4]-···[AuI2]- Complex Trapped in the Solid State by Tetramethylammonium Cations.

A discrete π-hole···σ-hole dimer is synthesized and X-ray characterized. It presents a perfect thumbtack geometry where the σ-hole of the linear [AuI2]- anion points to the π-hole located above the central Au-atom of the [AuI4]- anion. Such discrete π-hole···σ-hole dimers are unprecedented in literature, since all mixed-valence gold(I/III) iodide compounds reported to date form infinite ···([AuI4]-···[AuI2]-) n ·· chains in the solid state. If an excess of iodine is used for the synthesis, triiodide [I3]- ions are partially incorporated into the [AuI2]- sites, forming infinite chains. The nature of the anion···anion interaction has been studied considering two possibilities: (i) a π-hole coinage bond or (ii) σ-hole halogen bond using high-level density functional theory calculations, the quantum theory of atoms in molecules, and the noncovalent interaction plot index.

The effect and mechanism of excessive iodine on the endothelial function of human umbilical vein endothelial cells.

Iodine excess (IE) can cause thyroid dysfunction, thyroid diseases can adversely affect cardiovascular function. Accordingly, this study was to explore the direct and indirect effects of IE on endothelial function. Nthy-ori 3-1 and HUVECs cells were treated with potassium iodide (KI). CCK-8, LDH leakage, Elisa, RT-PCR and Western blotting were used to detect relevant indicators. Results showed that a certain level of KI can directly and indirectly reduce the viability of HUVECs and increase cytotoxicity. KI decreased the expression of ET-1 and VWF in HUVECs, inhibited the secretion of ET-1 in culture medium, and increased the expression of IL-6 and TNFα in HUVECs or Nthy-ori 3-1 cells alone. In the co-culture system, KI decreased the expression of ET-1 and THBD and increased the expression of TNFα and IL-6. Collectively, IE can directly and indirectly inhibit endothelial function of endothelial cells, which may be related to its induced inflammatory response.

The SELFI Study: Iodine Excess and Thyroid Dysfunction in Women Undergoing Oil-Soluble Contrast Hysterosalpingography.

Hysterosalpingography (HSG) with oil-soluble contrast medium (OSCM) improves pregnancy rates. However, OSCM has high iodine content and long half-life, leading to potential iodine excess. This work aimed to determine the pattern of iodine excess after OSCM HSG and the effect on thyroid function. A prospective cohort study was conducted of 196 consecutive consenting eligible women without overt hypothyroidism or hyperthyroidism. All completed the study with compliance greater than 95%. Participants underwent OSCM HSG (Auckland, 2019-2021) with serial monitoring of thyrotropin (TSH), free thyroxine (FT4), and urine iodine concentration (UIC) for 24 weeks. The main outcome measure was the development of subclinical hypothyroidism (SCH), defined as a nonpregnant TSH greater than 4 mIU/L with normal FT4 (11-22 pmol/L) in those with normal baseline thyroid function. Iodine excess (UIC ≥ 300 μg/L) was almost universal (98%) with UIC peaking usually by 4 weeks. There was marked iodine excess, with 90% and 17% of participants having UIC greater than or equal to 1000 μg/L and greater than 10 000 μg/L, respectively. Iodine excess was prolonged with 67% having a UIC greater than or equal to 1000 μg/L for at least 3 months. SCH developed in 38%; the majority (96%) were mild (TSH 4-10 mIU/L) and most developed SCH by week 4 (75%). Three participants met the current treatment guidelines (TSH > 10 mIU/L). Thyroxine treatment of mild SCH tended to improve pregnancy success (P = .063). Hyperthyroidism (TSH < 0.3 mIU/L) occurred in 9 participants (5%). OSCM HSG resulted in marked and prolonged iodine excess. SCH occurred frequently with late-onset hyperthyroidism occasionally. Regular thyroid function tests are required for 6 months following this procedure.

Iodine deficiency and thyroid dysfunction: Current scenario in Nepal

Iodine deficiency is a major cause of thyroid disorders worldwide. Nepal lies in the endemic area of iodine deficiency which was previously referred to as Himalayan goiter belt, with high prevalence of iodine deficiency disorders including goiter, cretinism and hypothyroidism. With effective implementation of universal salt iodization program, Nepal has a successful public health story to share having drastically reduced the iodine deficiency disorders. Moreover, challenge has appeared with rising number of excess iodine states. Thyroid dysfunction is growing higher and the increasing proportion of hyperthyroidism is particularly concerning. Time has come for us to suitably review the standards of salt iodization and control the increasing number of cases with thyroid dysfunction by the coordinated efforts of all stakeholders, along with sustaining the optimal level of iodine.

Factors associated with inadequate urinary iodine concentration among pregnant women in Mbeya region Tanzania.

Background: Insufficient and excessive iodine intake during pregnancy can lead to serious health problems. In Tanzania, information available on iodine status during pregnancy is minimal. The aim of this study was to assess the iodine status and its association with socio-demographic factors in pregnant women in the Mbeya region, Tanzania. Method: A cross sectional survey involving 420 pregnant women (n=420) registered in Reproductive and Child Health Clinics was conducted. Data were collected via interviews and laboratory analysis of urinary iodine concentration (UIC). Results: Median UIC was 279.4μg/L (+/-26.1) to 1915μg/L. Insufficient iodine intake (UIC below 150μg/L) was observed in 17.14% of participants, sufficient intake in 24.29% and 58.57% had intakes above the recommended level (&gt;250μg/L). Pregnant women who consume fish had an increased risk of insufficient iodine [Adjusted OR7= 2.60 (95%CI 1.31-5.15)] while the risk was lower for those who attended primary education compared to non-formal education [Adjusted OR= 0.29 (95%CI 0.08-0.99)]. Pregnant women resident in Mbarali district aged between 35-49 years were associated with an increased risk of UIC above recommended level [Adjusted OR=4.09 (95%CI 1.85-9.010] and [Adjusted OR=2.51 (95%CI 0.99-6.330] respectively . Conclusion: This study demonstrated a significant relationship between geographical factors (residence in the Mbarali district) and excess median urine iodine concentration, in addition, this study also found an association between consumption of freshwater fish and insufficient mean urine iodine concentration as indicated by the World Health Organization recommendation. Therefore, educational programs on iodine intake are needed as attending primary education was found to be a protective factor for insufficient median urine iodine concentration.

Mechanisms of Sodium/Iodide Symporter-Mediated Mammary Gland Iodine Compensation during Lactation.

This research aimed to investigate the compensation mechanism of iodine deficiency and excess in the mammary gland during lactation. Female rats were divided into the low iodine group (LI), the normal iodine group (NI), the 10-fold high iodine group (10HI) and the 50-fold high iodine group (50HI). We measured the iodine levels in the urine, blood, milk, and mammary gland. The protein expression of sodium/iodide symporter (NIS), DPAGT1, and valosin-containing protein (VCP) in the mammary gland was also studied. The 24-hour urinary iodine concentration, serum total iodine concentration, serum non-protein-bound iodine concentration, breast milk iodine concentration, and mammary gland iodine content in the 50HI group were significantly higher than those in the NI group (p < 0.05). Compared with the NI group, NIS expression in the 50HI group significantly decreased (p < 0.05). DAPGT1 expression was significantly higher in the LI group than in the NI group (p < 0.05). The expression level of VCP was significantly increased in the 10HI and 50HI groups. In conclusion, milk iodine concentration is positively correlated with iodine intake, and the lactating mammary gland regulates the glycosylation and degradation of NIS by regulating DPAGT1 and VCP, thus regulating milk iodine level. However, the mammary gland has a limited role in compensating for iodine deficiency and excess.

Prevalence of Excessive Iodine Intake in Pregnancy and Its Health Consequences: Systematic Review and Meta-analysis.

The objective was to estimate the prevalence of excessive iodine intake in pregnant women and to investigate the consequences for maternal-fetal health. The systematic review was based on PRISMA. The search was conducted in September 2021 in LILACS, PubMed/MEDLINE, Science Direct, and SCOPUS databases. Observational studies that assessed excessive nutritional iodine status in pregnancy diagnosed by urinary iodine concentration and associated it with biomarkers of thyroid health function were included. Study selection, data extraction, and risk of biased evaluation were performed independently. Meta-analysis was calculated using a fixed and random effect model, and heterogeneity was assessed by the chi-square test. Meta-regressions were performed to identify the causes of heterogeneity using the Knapp and Hartung test. Nine studies were included in the systematic review, and eight in the meta-analysis. The prevalence of excessive iodine intake in 10,736 pregnant women in different regions of the world was 52%. The main implications for pregnant women were hypothyroxinemia, hypothyroidism, and hyperthyroidism. For the newborn, macrosomia and thyroid dysfunction. In addition, drinking water with high iodine intake contributed to excessive iodine intake. Therefore, the prevalence of iodine excess was 52%, with high heterogeneity among studies, explained by trimester of gestation and FT4 level; therefore, the farther the trimester of gestation and the lower the FT4, the higher the prevalence of iodine excess. PROSPERO Registration: CRD420206467 ( https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=206467 ).

A microfluidic paper-based analytical device for iodometric titration of ascorbic acid and dopamine

A simple, rapid, and on-site iodometric titration with minimal preparation was devised utilizing a novel combination of traditional redox titration and microfluidic paper-based analytical devices (μPADs). The star-shaped pattern titration μPADs consists of a central sample loading zone connected to ten lateral reaction/detection reservoirs. The reaction reservoirs contain various concentrations of copper (II) acetate monohydrate with well-defined concentration gradient intervals and a fixed concentration of potassium iodide. This will result in a gradient of yellow color indicating iodine liberation as titrant in lateral reservoirs. The titration is stimulated when the test solution is applied to the central sample zone. As soon as the sample solution reaches the reaction zones (30 sec. after sample introduction), a constant concentration of amylose solution is added to the detection reservoirs, which serves as an indicator. The analyte is oxidized by the liberated iodine and the excess iodine reacts with amylose indicator, characterized by the formation of dark brownish-blue color. Therefore, the concentrations of target analyte solutions can be determined just in 30 sec., totally instrument-free and directly by naked-eye without calibration. The proposed μPADs are capable of determining ascorbic acid and dopamine solutions ranging from 1.0 × 10−5 M to 1.0 × 10−2 M. The detection lower limit is 1.0 × 10−5 M which is too difficult to measure using conventional volumetric iodometric titration. The reproducibility of the proposed method is lower than ± 5 % for five replicate measurements. The feasibility of the designed μPADs was confirmed by analysis of real samples and the results are highly consonant with those obtained from standard methods.

High intakes of iodine among women during pregnancy and the postpartum period has no adverse effect on thyroid function.

Given the high consumption of seaweed soup by pregnant and lactating Korean women, concerns have been raised about excessive iodine intake. We evaluated the effects of maternal iodine intake on maternal thyroid function and birth outcomes. We also evaluated iodine intake via seaweed soup during late pregnancy and theearly postpartum period. A total of 349 pregnant women of the Ideal Breast Milk cohort were recruited in late pregnancy, of whom 302 revisited after delivery. Three-day dietary records were assessed at each visit. Blood was collected for thyroid function test. Obstetrical and birth outcomes were obtained. The median dietary iodine intake was 459μg/day (interquartile range [IQR] 326.5-647.4μg/day) during pregnancy. Dietary iodine intake by quartile was not significantly associated with maternal thyroid status, or obstetrical or neonatal outcomes. However, the dietary iodine intake in the early postpartum period was 1759μg/day (IQR 1026.7-2491.1μg/day) because of a marked increase in seaweed soup consumption. Of all women, 25.8% consumed seaweed soup more than once over the 3days of dietary records when pregnant, but the figure rose to 93.4% postpartum. Of postpartum women who consumed seaweed soup daily, the median dietary iodine intakes were 1355, 2394, and 3063μg/day (soup at one, two, and three-or-four meals). In these iodine-replete pregnant women, dietary iodine intake during pregnancy showed no effect on maternal thyroid function or birth outcomes. However, iodine intake in the early postpartum period was markedly increased by the frequency of seaweed soup consumption.

Species transformation and removal mechanism of various iodine species at the Bi2O3@MnO2 interface

Long-term exposure to excessive iodine via drinking water significantly increases the risk of thyroid diseases. Further, the mechanisms and feasible technologies for iodine removal are far from being well elucidated. In this study, we constructed a heterogeneous Bi2O3@MnO2 interface with oxidation and adsorption efficiency toward iodide (I−), and investigated the performance and mechanisms involved in iodine removal. Bi2O3@MnO2 at the optimized Bi/Mn ratio of 0.05:1 had a maximum adsorption capacity of 1.19, 1.21, and 1.06 mg/g toward I−, iodine elemental (I2), and iodate (IO3−), respectively. According to the density functional theory (DFT) calculation, Bi2O3@MnO2 had an adsorption energy of -2.34, -2.11, and -3.89 eV for I−, I2, and IO3−, and exhibited a better band structure and state density character for iodine removal. Based on the results of XPS, HPLC, and LC-ICP-MS characterization, Bi2O3 plays an important role in adsorbing and capturing I− whereas MnO2 dominates the moderate oxidation of I− and the adsorption of I− and I2. The adsorbed I− and I2 concentrations on the Bi2O3@MnO2 surfaces were 146.3 μg/L and 18.3 μg/L. Notably, IO3− was not detected owing to its moderate oxidation effect. The coexisting ions of chloride (Cl−) and bromide (Br−) tended to occupy the Bi2O3 lattice and form insoluble BiOCl and BiOBr. Further, reductive species, such as sulphite (SO32−), may reduce MnO2 to Mn(III) and Mn(II). The synergistic effect between moderate oxidation and adsorption led to Bi2O3@MnO2 with high iodine removal capability. Overall, this study proposes a strategy for designing suitable interfaces and adsorbents for iodine removal; however, further studies are necessary to advance its application in practice.