What Iodine Intervention Measures Should Be Taken in Different Water Iodine Areas? Evidence from a Cross-sectional Chinese Survey

A Meta-Analysis of the Prevalence of Children Goiter in High Water Iodine Areas of China

Although there are now a large number of studies confirming that high iodine levels can cause goiter, there is controversy and a lack of quantitative data. A systematic search of PubMed, Web of Science, China National Knowledge Infrastructure, Wanfang Database, and China Biomedical Database for literature on high iodine and goiter in children was performed with a time limit from January 2013 to October 2023. After screening the literature based on the inclusion criteria, extracting the literature data, and evaluating the risk of bias of the included studies, a single-arm meta-analysis was performed using R 4.0.4 software. Twenty-three studies with a total of 50,980 subjects were included. Meta-analysis showed that the prevalence of goiter among children in water-borne iodine-excess areas was 6.0% [95% CI (4.3%, 7.6%)], and subgroup analyses showed that the prevalence of goiter in children with water iodine 100.1-150 µg/L, 150.1-300 µg/L, and > 300 µg/L was 7.5% [95% CI (0.0%, 15.8%)], 5.5% [95% CI (3.1%, 8.0%)], and 10.2% [95% CI (6.7%, 13.6%)], respectively, and the difference was statistically significant (P < 0.01); The prevalence of goiter among children in the northern China (5.8% [95% CI (4.1%, 7.5%)]) was higher than that in the southern China (3.5% [95% CI (1.0%, 6.0%)]) (P < 0.01); the prevalence of goiter in children with urinary iodine levels 100-199 µg/L, 200-299 µg/L, and ≥ 300 µg/L was 2.4% [95% CI (1.9%, 2.9%)], 3.3% [95% CI (1.9%, 4.8%)], and 7.3% [95% CI (4.4%, 9.9%)], respectively, the difference was statistically significant (P < 0.01); the prevalence of goiter in children aged 8, 9, 10, 11, and 12 years old was 5.1% [95% CI (3.9%, 6.4%)], 8.0% [95% CI (4.0%, 11.9%)], 6.2% [95% CI (3.9%, 8.5%)], 5.5% [95% CI (0.0%, 13.2%)], and 5.4% [95% CI (0.0%, 15.1%)], and when age ≥ 9 years, the relationship between goiter prevalence and age showed a trend toward decreasing with age, but the relationship between different age was no statistical difference in the prevalence of goiter between ages. urinary iodine. The prevalence of goiter in children was higher in areas with high water iodine; the prevalence of goiter in children in the north was significantly higher than that in the south; the prevalence of goiter in children tends to increase with increased urinary iodine levels.

How did we eliminate the hazards of water-borne excessive iodine in northern China?

Drinking water is the main cause of iodine excess among Chinese residents and we have found that water iodine concentration (WIC) reduction was the effective intervening measure. In this study, to eliminate the hazards of water-borne excessive iodine, we firstly investigated the WIC of villages in Tianjin in 2017 to determine the distribution range. Secondly, the risk characterization of excessive iodine on residents in 6∼< 9 years old, 9∼< 12 years old, 12∼< 15 years old, 15∼< 18 years old and adults were evaluated, and the safe upper limit of WIC was determined. Finally, WIC was investigated again after the completion of WIC reduction in water-borne excessive-iodine villages in 2020, and the differences in urinary iodine concentration (UIC) and thyroid volume (Tvol) of children aged 8-10 years before and after WIC reduction were analyzed. The WIC of 2459 villages surveyed was 22.30 (8.60-58.80) μg/L and the maximum was 514 μg/L. There were 422 villages with WIC > 100 μg/L. Under the conditions of non-iodized salt intake, recommended amount of iodized salt intake and actual amount intake, the maximum of excessive iodine exposure hazard quotient (HQ) were the highest in the age group of 6∼< 9 years, which were 2.300, 2.663 and 2.771, the safe upper WIC limits were 223 μg/L, 142 μg/L and 118 μg/L and villages with HQ> 1 accounted for 4.14%, 6.09% and 6.88% of all villages, respectively. After the WIC reduction, the WIC of the former water-borne iodine-excess villages decreased to < 100 μg/L, and the UIC and Tvol of children decreased (both P < 0.001) and was within normal range. Determining the distribution range of water-borne iodine-excess areas, exploring appropriate intervening measure, carrying out risk assessment, determining the WIC safe upper limit, intervening and evaluating the intervention effect can be the process to eliminate the hazards of water-borne excessive iodine.

Association between different water iodine exposures and thyroid cancer: A retrospective study of high water iodine areas in China from 2009 to 2020

In recent years, the incidence of thyroid cancer has been on a significant rise worldwide, and a number of environmental factors have been suspected to be risk factors for thyroid cancer, especially the relationship between iodine intake and thyroid cancer has attracted attention. In this study, we want to assess the relationship between different water iodine exposures and thyroid cancer incidence before and after water alteration in areas with high water iodine in China. Thyroid cancer patients (2009-2020) were enrolled at two hospitals, both in Heze City, Shandong Province, an area with high water iodine levels. According to the criteria of the study, 5826 cases out of 8785 cases were selected for inclusion in the study. Before and after water alteration, the incidence of thyroid cancer was highest in areas with water iodine concentrations of 200-300 μg/L in high iodine areas. In areas where water iodine decreased to adequate iodine levels, there was a strong negative correlation between the decreased level of water iodine and the incidence of thyroid cancer. In addition, in cases with pathology reports, we found that the greater the decrease in water iodine values, the markedly smaller the maximum diameter of the thyroid cancer lesions. Taken together, these findings suggest that we should continue to monitor the incidence of thyroid cancer in areas with high water iodine and continue to optimize population iodine intake to reduce the incidence of thyroid cancer.

Serum thyroglobulin as a biomarker of iodine excess and thyroid disease occurrence in adults

BACKGROUND

Thyroglobulin (Tg) is considered a sensitive indicator of iodine deficiency. However, the usefulness of Tg as a biomarker of excess iodine is uncertain. The present study aimed to determine the influence of different iodine intake on serum Tg levels, evaluate the influence of thyroid diseases on the distribution of Tg, and identify the factors that may affect Tg levels.

METHODS

A cross-sectional survey with a total of 1208 adults was conducted in different water iodine areas in China. Urinary iodine concentration (UIC), water iodine concentration (WIC), serum Tg, thyroid-stimulating hormone (TSH), and thyroid antibodies were measured. The thyroid volumes and nodules were measured by B-scan ultrasound.

RESULTS

Based on the WIC data, subjects were divided into three groups. Based on the median urinary iodine concentration (MUIC) data, the iodine levels were adequate, more than adequate, and excess for the WIC < 10 μg/L group, 10 μg/L ≤ WIC ≤ 100 μg/L g, and WIC > 100 μg/L groups, respectively. The median Tg was significantly higher in the excess iodine group than in the adequate iodine group and the more than adequate iodine group (14.6 μg/L vs.12.7 μg/L, P = 0.042; 14.6 μg/L vs.12.5 μg/L, P = 0.004). Multiple linear regression analysis showed that excess iodine intake, goitre, thyroid nodules, and hypothyroidism were significantly related to higher serum Tg levels.

CONCLUSION

Serum Tg level can be a promising biomarker of excessive iodine intake, but other factors, especially the presence of thyroid disease, should be considered when using this parameter.

Effects of Sodium Chromate Exposure on Gene Expression Profiles of Primary Rat Hepatocytes (In Vitro)

Chromium exposure has adverse impacts on human health and the environment, whereas chromate-induced hepatotoxicity's detailed mechanism is still unclear. Therefore, the purpose of the current study was to reveal the crucial signaling pathways and genes linked to sodium chromate-induced hepatotoxicity. GSE19662, a gene expression microarray, was obtained from Gene Expression Omnibus (GEO). Six primary rat hepatocyte (PRH) samples from GSE19662 include sodium chromate-treated (n = 3) and the control PRH samples (n = 3). A total of 2,525 differentially expressed genes (DEGs) were obtained, especially 962, and 1,563 genes were up- and downregulated in sodium chromate-treated PRHs compared to the control. Gene ontology (GO) enrichment analysis suggested that those DEGs were involved in multiple biological processes, including the response to toxic substances, the positive regulation of apoptotic process, lipid and cholesterol metabolic process, and others. Signaling pathway enrichment analysis indicated that the DEGs were mainly enriched in MAPK, PI3K-Akt, PPAR, AMPK, cellular senescence, hepatitis B, fatty acid biosynthesis, etc. Moreover, many genes, including CYP2E1, CYP1A2, CYP2C13, CDK1, NDC80, and CCNB1, might contribute to sodium chromate-induced hepatotoxicity. Taken together, this study enhances our knowledge of the potential molecular mechanisms of sodium chromate-induced hepatotoxicity.

Effects of Nano-Cu2O on the Productivity in the Cu-Stripped Chinese Merino Sheep

This research is to study the effects of nano-Cu₂O on blood parameters, growth performance, and wool yield in the Cu-stripped ranches, and provide reference for further study on prevention and treatment in Cu-deficient Chinese Merino sheep. We selected twenty Chinese Merino sheep from Cu-deficient and normal ranch, respectively. The results have shown that the Cu content in the soils, forages, blood, and wool from Cu-deficient ranches was significantly lower than those from normal ranches (P < 0.01). There were no significant differences in the contents of other elements. Treatment experiments of nano-Cu₂O were carried out for 50 days. We found that the Cu content in the blood was increased continuously in the sheep after adding nano-Cu₂O, and reached the highest level at 40 days. The levels of Hb, RBC, PCV, MCV, and MCH in the nano-Cu₂O-fed animals were remarkably higher than those in the control animals (P < 0.01). The daily gain and wool yield in the nano-Cu₂O-fed animals were also significantly higher than those in the control sheep (P < 0.01). Therefore, adding nano-Cu₂O not only remarkably increases the Cu content in the blood, but also greatly improves the daily gain and wool yield in Cu-deficient animals.

Molybdenum and Cadmium Co-induce Pyroptosis via Inhibiting Nrf2-Mediated Antioxidant Defense Response in the Brain of Ducks

Excess molybdenum (Mo) and cadmium (Cd) are harmful to animals, but the neurotoxic mechanism co-induced by Mo and Cd is unclear. To estimate the effects of Mo and Cd co-exposure on pyroptosis by nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant defense response in duck brains, 40 healthy 7-day-old ducks were randomly assigned to 4 groups and fed diet supplemented with Mo or/and Cd for 16 weeks, respectively. Results showed that Mo or/and Cd markedly increased Mo and Cd contents; decreased iron (Fe), copper (Cu), zinc (Zn), and selenium (Se) contents, elevated malondialdehyde (MDA) content; and decreased total-antioxidant capacity (T-AOC), total-superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities accompanied by pathological damage in brain. Additionally, Mo or/and Cd inhibited Nrf2 pathway via decreasing Nrf2, CAT, SOD1, glutathione S-transferase (GST), hemeoxygenase-1 (HO-1), NAD (P) H:quinone oxidoreductase 1 (NQO1), glutamate-cysteine ligase catalytic subunit (GCLC), and modifier subunit (GCLM) mRNA levels and Nrf2 protein level, which induced pyroptosis through upregulating nucleotide oligomerization domain-like receptor protein-3 (NLRP3), apoptosis-associated speck-like protein (ASC), gasdermin A (GSDMA), gasdermin E (GSDME), interleukin-1β (IL-1β), interleukin-18 (IL-18), Caspase-1, NIMA-related kinase 7 (NEK7) mRNA levels and NLRP3, Caspase-1 p20, gasdermin D (GSDMD), ASC protein levels and IL-1β, and IL-18 contents. Besides, the changes of these indicators were most apparent in the Mo and Cd co-treated group. Collectively, the results certificated that Mo and Cd might synergistically induce pyroptosis via inhibiting Nrf2-mediated antioxidant defense response in duck brains, whose mechanism is closely related to Mo and Cd accumulation.

Application of oral inorganic iodine in the treatment of Graves' disease

Iodine is a crucial trace element for the human body and the basic raw material for the synthesis of thyroid hormones. Oral inorganic iodine includes dietary iodine and therapeutic iodine, both of which are closely associated with thyroid immunity and metabolism. Graves' disease (GD), also known as diffuse toxic goiter, is characterized by hyperthyroidism and high iodine metabolism. Clinically, patients diagnosed with GD are often asked to limit iodine intake or even avoid iodine in their diet. The latest research has demonstrated that the interference of dietary iodine with antithyroid drugs (ATDs) treatment may be overestimated. In addition, as a medication for GD treatment, the administration of inorganic iodine has shown positive results in patients with mild hyperthyroidism, a low thyroid autoantibody concentration, a small thyroid volume, a high iodine diet and so on. Inorganic iodine may also be used as an alternative when patients experience side effects with traditional ATDs and for those who still prefer conservative treatment. Due to its low teratogenicity, blood toxicity and bone marrow toxicity, inorganic iodine plays a unique role in special populations, such as pregnant or lactating patients and patients receiving tumor radiotherapy or chemotherapy. In this review, the research progress, biological function, doses and effects, applicable populations and specific applications of dietary iodine and therapeutic iodine are summarized to provide references for the diagnosis and treatment of GD, thus improving the quality of life of GD patients.

Nano-selenium and Macleaya cordata Extracts Improved Immune Function and Reduced Oxidative Damage of Sows and IUGR Piglets After Heat Stress of Sows in Late Gestation

To investigate the effects of nano-selenium (nano-Se) and Macleaya cordata extracts (MCE) on immune function and oxidative damage of sows and intrauterine growth retardation (IUGR) piglets exposed to heat stress (HS) in large-scale farms, a 2 × 2 factorial design was adopted in this test, and the two factors were nano-Se (0, 0.50 mg/kg) and MCE (0, 500 mg/kg). A total of 80 sows ([Landrace × Yorkshire] × Duroc, parity 2) were used in a 25-day trial from day 90 of gestation to delivery with 20 replications per group and 1 sow per replication. The dietary treatments of sows were as follows: (1) CON group, basic diet (0.30 mg/kg added Se, sodium selenite); (2) Nano-Se group, basic diet (0.00 mg/kg added Se) + 0.50 mg/kg added nano-Se; (3) MCE group, basic diet (0.00 mg/kg added Se) + 500 mg/kg added MCE; and (4) Combined group, basic diet (0.00 mg/kg added Se) + 0.50 mg/kg added nano-Se and 500 mg/kg added MCE. The activities of serum SOD, CAT, and GSH-Px of sows and IUGR piglets were significantly increased in MCE group and combined group, and the MDA content was extremely decreased. There were extreme differences in serum IgG level of sows and IUGR piglets, colostrum, and serum IgM level of IUGR piglets in MCE group and combined group compared with CON group. Maternal combined diets increased greatly the levels of serum IL-10 and IFN-γ of sows and IUGR piglets, and decreased extremely the contents of serum IL-1β and TNF-α. MCE alone or combination with nano-Se in sow diets decreased greatly mRNA level of Hsp70 and increased mRNA level of Hsp27 in sows and IUGR piglets. In conclusion, nano-Se and/or MCE can be added to sow diets for the amelioration of HS-induced oxidative damage through improving immune function.

Effect of Foliage Dressing in Nano-Potassium Molybdate on Daily Gain and Antioxidant Function in Grazing the Chinese Merino Sheep

The study was implemented for exploring influences of nano-K₂MoO₄ on the daily gain and antioxidant function of Chinese merino sheep in the native pasture, Xinjiang Uygur Autonomous Region, Northwest of China. Eighty of the sheep, weight of (45.56 ± 2.35) kg, were randomly distributed to the tested areas for 90 days, 20 sheep/group. The findings showed that the contents of Mo and N in the forage of applying nano-K₂MoO₄ were extremely higher than those in the control pastures (P <0.01). The daily gain in the fertilized groups were remarkably lower than that in the control group (P <0.01). The harvest of forage in the fertilized pastures were significantly higher than those in control (P <0.01). The contents of Mo in blood and liver in grazing the Chinese merino sheep were extremely higher than those from the control group (P <0.01). The contents of Cu in blood and liver in grazing the Chinese merino sheep were extremely lower than those in the unfertilized pastures (P <0.01). The levels of hemoglobin (Hb), blood platelet (PLT), and erythrocyte count (RBC) in animals from the fertilized pastures were extremely lower than those in the control pastures (P < 0.01). The activities of SOD, GSH-Px, and CAT in serum were significantly lower than those in group C. The serum MDA levels were significantly higher than those in the control group (P < 0.01). In conclusion, the application of nano-K₂MoO₄ in pastures can greatly improve the yield of forage, but strikingly decreased the daily gain and antioxidant function in grazing the Chinese merino sheep.

Selenium Alleviates Cerebral Ischemia/Reperfusion Injury by Regulating Oxidative Stress, Mitochondrial Fusion and Ferroptosis

To clarify the potential role of selenium (Se) on cerebral ischemia/reperfusion (I/R) injury, we utilized mouse middle cerebral artery occlusion (MCAO) followed by reperfusion as an animal model and oxygen-glucose deprivation and reoxygenation (OGD/R) to treat N2a cells as a cell model, respectively. MCAO model was established in mice and then divided into different groups with or without Se treatment. TTC staining was used to observe whether the cerebral I/R modeling was successful, and the apoptosis level was determined by TUNEL staining. The expression of GPx-4 and p22phox was assessed by western blot. In vitro experiments, the OGD/R induced oxidative stress in N2a cells was assessed by levels of GSH/GSSG, malondialdehyde, superoxide dismutase and iron content, respectively. QRT-PCR was used to detect the mRNA levels of Cox-2, Fth1, Mfn1 and mtDNA in N2a cells. JC-1 staining and flow cytometry was performed to detect the mitochondrial membrane potential. Se treatment alleviated cerebral I/R injury and improved the survival rate of mice. Additionally, Se treatment apparently attenuated oxidative stress and inhibited iron accumulation in MCAO model mice and OGD/R model of N2a cells. In terms of its mechanism, Se could up-regulate Mfn1 expression to alleviate oxidative stress and ferroptosis by promoting mitochondrial fusion in vivo and vitro. These findings suggest that Se may have great potential in alleviating cerebral I/R injury.