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.

Survey of iodized salt coverage in areas with different water iodine concentrations and the iodine status of local women.

PURPOSE: There were only two definitions of iodine-deficient (water iodine concentration < 10 µg/L) and iodine-excess areas (water iodine concentration > 100 µg/L) in China before 2020. Areas with water iodine concentration between 10 and 100 µg/L implement the same policy as iodine-deficient areas to provide iodized salt. The definition of iodine-adequate areas was formulated in 2020 for the first time. The paper aims to investigate the coverage rate of iodized salt (CR) in different areas defined according to the latest national standards, evaluate the iodine status of local women, and provide a basis for the revision and improvement of relevant policies. METHODS: A total of 1948 women aged 18-60 were recruited from the iodine extra-high areas (IEHA), iodine-excess areas (IEA), iodine-adequate areas (IAA), inland iodine-deficient areas (IIDA), and coastal iodine-deficient areas (CIDA). Information on daily diet was collected with the Food Frequency Questionnaire. Drinking water, salt, food, and urine samples were collected and tested in our laboratory. Based on the recommended daily iodine intake, we assessed whether the subjects' daily iodine intake levels were adequate. RESULTS: The CR and the median urinary iodine concentrations (UICs) were 4.02% and 98.03 µg/L in CIDA, 89.74% and 144.93 µg/L in IIDA, 26.55% and 178.60 µg/L in IAA, 8.78% and 446.5 µg/L in IEA, 3.95% and 605.4 µg/L in IEHA, respectively. The differences among these five areas were statistically significant (P < 0.0001). The daily dietary iodine intakes were mainly from drinking water in IAA (63.92%), IEA (92.29%), and IEHA (92.93%), and were mainly from iodized salt in IIDA (59.22%) and food in CIDA (86.6%). CONCLUSION: Women in IAA and IIDA were in an adequate iodine state. Women in IEA and IEHA were in an iodine-excess state, and it is necessary to carry out water improvements projects. Women in CIDA were in a slight iodine-deficient state, and health education on scientific iodine fortification should be strengthened to increase iodine intake.

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.

Study on the Relationship Between Serum Iodine and Thyroid Dysfunctions: a Cross-Sectional Study.

The relationship between serum iodine (SIC) and thyroid dysfunctions in adults is poorly understood, and this study aimed to explore their relationship. A total of 1320 participants were included in the final analysis. We collected basic demographic information, blood, and spot urine samples to determine serological indices and iodine nutritional status. The median (IQR) of urinary iodine (UIC)/urinary creatinine (UCr), UIC, SIC were 138.1 (91.1, 207.6) µg/g, 155.8 (94.5, 211.1) µg/L, and 70.6 (59.8, 83.9) µg/L, respectively. The 90% reference ranges for UIC/UCr and SIC were 66.5-349.8 mg/g and 49.3-97.1 µg/L. SIC was positively correlated with UIC and UIC/UCr. The prevalence of overt hypothyroidism and subclinical hypothyroidism in female was significantly higher than that in male (P = 0.02, P = 0.002). In male, subjects above the upper reference value of SIC (97.1 µg/L) had a higher risk of subclinical hyperthyroidism (OR = 4.46, 95% CI: 1.29, 12.8) and overt hypothyroidism (OR = 5.59, 95% CI: 1.88, 6.42). In female, subjects below the lower reference value of SIC (49.3 µg/L) had a higher risk of overt hypothyroidism (OR = 2.18, 95% CI: 1.10, 4.06), TgAb positive (OR = 1.97, 95% CI: 1.15, 3.32) and TPOAb positive (OR = 2.48, 95% CI: 1.41, 4.26). In conclusion, serum iodine can be used as an indicator to evaluate iodine nutritional status and thyroid dysfunctions. Higher serum iodine concentration was associated with an increased risk of subclinical hyperthyroidism and overt hypothyroidism in men; lower serum iodine concentration was associated with an increased risk of overt hypothyroidism and positive TgAb and TPOAb in women.

Relationships between the serum TPOAb and TGAb antibody distributions and water iodine concentrations, thyroid hormones and thyroid diseases: a cross-sectional study of 2503 adults in China.

The aim of this study was to explore the status of thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb) in three areas with differing water iodine concentrations; and to discuss the relationships between these two thyroid antibodies and thyroid diseases in the three areas. We investigated 2503 adults from three areas. Urinary iodine concentrations, thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), TPOAb, TGAb and thyroid volume (TV) were measured, and thyroid ultrasonography was performed. The positivity rates of TGAb(+), TPOAb(+) and TGAb(+) and TPOAb(+) or TGAb(+) were significantly higher in iodine fortification (IF) areas than iodine adequate (IA) areas (all P < 0·05). In IF and iodine excess areas, the positivity rates of TPOAb(+), TGAb(+) and TPOAb(+) or TGAb(+) significantly increased with age (all P for trend < 0·05). The levels of TSH, TV and the prevalence of overt hypothyroidism, subclinical hypothyroidism and goitre were significantly elevated in the thyroid antibody-positive groups in the three areas, but the FT3 was diminished (all P < 0·010). Positivity for TPOAb and TGAb was associated with an increased risk of subclinical hypothyroidism in the three areas. In areas with different median water iodine, positivity for both TPOAb and TGAb was associated with elevated TSH values. Notably, with the increased levels of TPOAb, the frequency of abnormally elevated TSH increased dramatically in the three areas.

Prevalence of thyroid nodules and its association with water iodine among Chinese men and women.

BACKGROUND: Because of the large change in iodine nutrition and other lifestyle in China, there is concern that thyroid nodules (TNs) may become epidemic. However, few data are currently available on the national prevalence of TNs. In addition, whether excess iodine in drinking water is associated with an increased risk of TNs, following universal salt iodization, has been less studied. We aim to estimate a national prevalence of TNs and its association with drinking water iodine. METHODS: We conducted a national survey of 9,381,032 adults, aged 18 years or older, from 30 provinces and municipalities in China, who underwent a thyroid ultrasound test from January 2018 to December 2018. Crude and standardized prevalence of TNs were estimated. We further evaluated the ecological association between province- or city-specific iodine levels in drinking water and the prevalence of TNs using linear regression. RESULTS: The age-standardized prevalence of TNs in men, women, and both sexes were 29.8%, 44.7%, and 37.1%, respectively. The prevalence increased with age from 22.7% (18-30 years) to 71.5% (≥70 years), and body mass index from 26.1% (<18.5 kg/m2) to 40.8% (≥28 kg/m2). Participants living in the eastern, northern, and northeastern regions had a higher prevalence of TNs (ranged from 38.7% to 43.7%) than those in other regions (ranged from 30.1% to 35.5%). The coastal residents (40.1%) had a higher prevalence of TNs than those in inlanders (35.4%). Higher levels of iodine in drinking water were linearly associated with increased prevalence of TNs, with Pearson correlation coefficients of 0.47 (P < 0.01) in men, 0.40 (P = 0.03) in women, and 0.46 (P = 0.01) in overall participants. CONCLUSION: This was a nationwide prevalence study of TNs in China, showing that TNs were common health problems, and increased concentration of iodine in drinking water was associated with a higher prevalence of TNs.

Relationship Between Thyroid Hormonal Status in Patients with a Hypothyroid Form of Hashimoto's Thyroiditis and Iodine Concentrations in Drinking Water.

The current study aimed to identify correlative and regressive dependencies between the water iodine concentration and the levels of TSH (thyroid-stimulating hormone), thyroglobulin antibodies (TgAbs), and thyroid peroxidase (TPOAb) in the serum of 168 in patients (34 men and 134 women) with a hypothyroid form of Hashimoto's thyroiditis who use water from the supply network and individual wells. Based on the water iodine concentration, low and moderate degrees of iodine endemia in the location of the patients were determined. In the groups of men and women using water from different water supply sources, there were direct correlations between the water iodine concentrations and the TgAbs and TPOAb titers as well as an inverse dependence between iodine and TSH levels. Multivariate regressive analysis indicated that TgAb and TSH in the group of women using water from a supply network and TPOAb titers in the group of women using well water were independent factors associated with water iodine concentrations. Statistically significant correlations and regressive dependencies between the water iodine concentrations and the biomarkers of the thyroid status of the patients indicate the risk of Hashimoto's thyroiditis progression, especially among women with additional iodine intake.

Relationship between water iodine and children's goiters.

Excessive iodine can lead to goiters. However, the relationship between the water iodine concentration (WIC) and goiter rate (GR) is unclear. This study aims to explore the factors that influence children's GR in areas with high WIC and analyse the threshold value of the GR increase associated with the WIC. According to the monitoring of the areas with high WIC in China in 2018-2020, a total of 54 050 children in eight high water iodine provinces were chosen. Drinking water, urine and edible salt samples of children were collected. The thyroid volume (Tvol) was measured. A generalised additive model (GAM) was used to analyse the relationship between the WIC and GR in children. Among the 54 050 children in areas with high WIC, the overall GR was 3·34 %, the median of water iodine concentration was 127·0 µg/l, the median of urinary iodine concentration was 318 µg/l and the non-iodised salt coverage rate (NISCR) was 63·51 %. According to the GAM analysis results, water iodine and urinary iodine are factors that influence the Tvol and GR, while the NISCR affects only the GR. When the WIC was more than 420 µg/l or the urinary iodine concentration was more than 800 µg/l, the GR increased rapidly. When the NISCR reached more than 85 %, the GR was the lowest. Thus, in areas with high WIC, WIC more than 420 µg/l may increase the risk of goiter, and the NISCR should be increased to over 85 % to avoid goiters in children.

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

The aim of this study was to assess the population's iodine nutrition and thyroid diseases in different water iodine areas and to offer suggestions to the governments of different countries to adjust the present policy in different water iodine areas. A cross-sectional survey was conducted in different water iodine areas in China. Urinary iodine, water iodine, salt iodine and thyroid function were determined. The thyroid volumes and nodules were measured by ultrasound. Upon categorization by water iodine level for the 10.0 ~ 39.9 µg/L, 40.0 ~ 100.0 µg/L and 100.1 ~ 150.0 µg/L areas, in adults, the prevalence of subclinical hypothyroidism was 9.28%, 5.35% and 11.07%, and the median urinary iodine (MUI) was 153.7 µg/L, 189.8 µg/L and 317.0 µg/L; in children of the three areas, the prevalence of goitre was 3.83%, 4.47% and 16.02%, and the MUI was 164.1 µg/L, 221.0 µg/L and 323.3 µg/L; in pregnant women of those areas, the MUI was 148.6 µg/L, 176.9 µg/L and 324.9 µg/L. Logistic regression results indicated that low iodine intake was a risk factor for developing hypothyroxinaemia in pregnant women. The iodine status of pregnant women is insufficient in areas with a median water iodine level of 10.0 ~ 39.9 µg/L. Low iodine intake increases the risk of developing hypothyroxinaemia in pregnant women. The iodine status of adults and children is excessive, and the iodine status of pregnant women is above the requirements in areas with a median water iodine concentration of 100.1 ~ 150.0 µg/L. Iodized salt, especially for pregnant women, should be supplied in areas with a median water iodine concentration of 10.0 ~ 39.9 µg/L to improve the iodine status of pregnant women. Supplying non-iodized salt is not enough to protect local residents from the harm from excess iodine in areas with a median water iodine concentration above 100.0 µg/L.

Analysis of surveillance results of iodine deficiency disorders in Jingdezhen City of Jiangxi Province from 2017 to 2020 / 中华地方病学杂志

Objective:To analyze the iodine content distribution of drinking water in Jingdezhen City, and master the status of prevention and control of iodine deficiency disorders (IDD), so as to provide a basis for adopting targeted control measures and scientific adjustment of control and prevention strategies.Methods:According to the "National Iodine Deficiency Disorders Surveillance Program" and the "National Water Iodine Content Survey Program for Drinking Water", the surveillance of IDD in Jingdezhen City was carried out from 2017 to 2020. Household edible salt samples from pregnant women and students aged 8 to 10 were collected to detect salt iodine content, and urine samples were collected to detect urinary iodine. Thyroid volume of students was measured by B-ultrasonography, and the rate of goiter was calculated. In 2017, the iodine content of drinking water in Jingdezhen City was investigated, and the results were analyzed.Results:From 2017 to 2020, a total of 1 800 students were examined for thyroid gland, and 11 students were found to have goiter, with an goiter rate of 0.61%. A total of 3 201 edible salt samples and 3 201 urine samples were collected from students, the median of salt iodine was 24.96-26.40 mg/kg, the consumption rate of qualified iodized salt was 98.50%-99.50%, and the median of urinary iodine was 172.56-218.35 μg/L. A total of 1 600 edible salt samples and 1 600 urine samples were collected from pregnant women, the median of salt iodine was 24.40-25.38 mg/kg, the consumption rate of qualified iodized salt was 97.25%-98.00%, and the median of urinary iodine was 161.55-205.60 μg/L. In 2017, a total of 667 water samples were collected from 52 villages and towns in 4 counties and districts. The median of water iodine of the 4 counties and districts was 0.6-3.2 μg/L, and that of the 52 villages and towns was 0.3-12.3 μg/L.Conclusions:The iodine nutrition level of students and pregnant women in Jingdezhen City is generally at an appropriate level, but the iodine content of drinking water is low. It is suggested to strengthen the health education and health promotion of IDD among key population, guide the residents to supplement iodine scientifically, and continuously eliminate the harm of IDD.

Investigation and analysis of thyroid nodules and goiter in school-age children in different water iodine areas of Jiangsu Province / 中华地方病学杂志

Objective:To analyze the detection rate of thyroid nodules and goiter in school-age children in different water iodine regions and investigate the difference of thyroid nodule and goiter in school-age children with different age, gender and body mass index (BMI) in Jiangsu Province.Methods:In 2017, three villages with water iodine values of 8.1, 51.2 and 115.4 μg/L (iodine deficient group, iodine appropriate group and iodine high group) were selected as survey sites in Xuzhou City, Jiangsu Province, where the supply of iodized salt was suspended. One primary school was selected from each village, and children aged 8 to 10 years old (age balance, half male and half female) were selected from each primary school as the survey subjects. Urine sample were collected, urinary iodine level was determined, height and weight were measured, and neck B ultrasound was performed.Results:A total of 131, 140 and 138 school-age children aged 8 to 10 years old were investigated in the iodine deficient group, iodine appropriate group and iodine high group, respectively, with a total of 409 children. The detection rates of thyroid nodules were 6.9% (9/131), 15.0% (21/140) and 16.7% (23/138), respectively, and the detection rates of goiter were 1.5% (2/131), 1.4% (2/140) and 6.5% (9/138) in the three groups, respectively. There were statistically significant differences in the detection rates of thyroid nodules and goiter in different water iodine groups (χ 2 = 6.92, 6.37, P < 0.05). The detection rates of thyroid nodules in different age groups were 9.5% (12/126), 11.3% (16/142) and 17.7% (25/141), the differences were statistically significant (χ 2 = 9.05, P < 0.05). The detection rates of thyroid nodules were 11.6% (24/207), 14.4% (29/202), and 12.5% (39/313), 16.9% (14/83), 0/9 and 0/4 in the subjects of different gender and BMI, the differences were not statistically significant (χ 2 = 0.69, P > 0.05). The detection rates of goiter in the subjects of different gender, age and BMI were 1.4% (3/207), 5.0% (10/202); 2.4% (3/126), 6.3% (9/142), 0.7% (1/141); 1.6% (3/313), 4.8% (4/83), 3/9 and 1/4. The differences were statistically significant (χ 2 = 4.07, 7.66, P < 0.05). Conclusion:The detection rate of thyroid nodules in school-age children in different water iodine regions in Jiangsu Province may have a certain relationship with age, and the detection rate of goiter may have a certain relationship with age, gender and BMI.

The relationship of different levels of high iodine and goiter in school children: a meta-analysis.

BACKGROUND: Over the past decade, the phenomenon of high urine iodine (HUI) and high water iodine (HWI) has become more common. But the risk of goiter caused by different levels of HUI and HWI remains unclear. OBJECTIVES: To explore the risk of goiter development caused by HUI and HWI, and compare the risk of goiter development from different levels of high iodine. METHODS: The Medline, Cochrane library, Embase, China National Knowledge Infrastructure and Wan fang databases were searched for relevant population-based studies investigating the link between high iodine levels and goiter development in mainland China. Three reviewers extracted data from the included studies independently, assessing the prevalence of goiter development due to high iodine. RESULTS: Taking 100 µg/L ≤ UIC < 300 µg/L (UIC = urinary iodine concentration) as the reference group, the odds ratio (OR) regarding high iodine levels and goiter formation was 1.74 (95% CI 1.50, 2.01, P < 0.001), if the water iodine concentration (WIC) was greater than 100 µg/L, the OR between goiter development and WIC was 4.74 (95% CI 1.15, 19.46, P = 0.001). The Linear trend analysis of HUI and goiter showed that the prevalence of goiter increased with the increase of UIC (χ2 = 734.605, P < 0.001). CONCLUSIONS: When the UIC ≥ 300 µg/L or the WIC ≥ 100 µg/L, the risk of goiter will increase. The higher the UIC, the greater the risk of goiter development. In order to improve the public thyroid health, we should adhere to the monitoring of urinary iodine and water iodine, and keep them at an appropriate level. TRIAL REGISTRATION: PROSPEROCR, CRD42020197620. Registered 8 August 2020, https://www.crd.york.ac.uk/PROSPERO/ .

Assessing the impact of drinking water iodine concentrations on the iodine intake of Chinese pregnant women living in areas with restricted iodized salt supply.

PURPOSE: The supply of non-iodized salt and the water improvement project have been conducted to reduce the iodine concentration in drinking water in areas with elevated water iodine. We aimed to assess the impact of water iodine concentration (WIC) on the iodine intake of pregnant women in areas with restricted iodized salt supply, and determine the cutoff values of WIC in areas with non-iodized salt supply. METHODS: Overall, 534 pregnant women who attended routine antenatal outpatient visits in Zibo Maternal and Child Health Hospital in Gaoqing County were recruited. The 24-h urine iodine excretion (UIE) in 534 samples and the iodine concentration in 534 drinking water samples were estimated. Urinary iodine excretion, daily iodine intake, and daily iodine intake from drinking water (WII) were calculated. The relationship between WIC and daily iodine take was analyzed. RESULTS: The median WIC, spot urine iodine concentration (UIC), and 24-h UIE were 17 (6, 226) µg/L, 145 (88, 267) µg/L, and 190 (110, 390) µg/day, respectively. A significant positive correlation was found between WIC and UIE (R2 = 0.265, p < 0.001) and UIC (R2 = 0.261, p < 0.001). The contribution rate of WII to total iodine intake increased from 3.0% in the group with WIC of < 10 µg/L to 45.7% in the group with WIC of 50-99 µg/L. CONCLUSION: The iodine content in drinking water is the major iodine source in pregnant women living in high-water iodine areas where iodized salt supply is restricted. The contribution rate of daily iodine intake from drinking water increases with the increase in water iodine concentration.

Iodine content in drinking water and drawing of water iodine distribution map in Qinghai Province / 中华地方病学杂志

Objective:To understand the water iodine content in Qinghai Province and draw a distribution map of water iodine, so as to provide a basis for scientific supplementation of iodine and continuous elimination of iodine deficiency hazards.Methods:In 2017, in all counties (cities, districts) in Qinghai Province, with townships (towns, streets, referred to as townships) as the unit, the residents' drinking water samples were collected, water iodine content was tested, the median water iodine was calculated, and the water iodine distribution map of Qinghai Province was drew.Results:Totally 1 836 drinking water samples were collected in 392 townships, the median water iodine was 1.7 μg/L. Townships that had the median water iodine < 5 μg/L, in the range of 5 to 10 μg/L and > 10 μg/L accounted for 80.6% (316/392), 17.1% (67/392) and 2.3% (9/392), respectively. Among all townships, the highest of the median water iodine was 24.8 μg/L. Based on the results, water iodine distribution map of Qinghai Province, water iodine distribution map of Xining City and water iodine distribution map of Haidong City were compiled.Conclusions:Iodine deficiency is widespread throughout natural environment in Qinghai Province. Hence, salt iodization measures to prevent iodine deficiency disorders should be implemented continuously. According to the water iodine distribution map, the people should be guided to supplement iodine scientifically.

Association between excessive chronic iodine exposure and the occurrence of papillary thyroid carcinoma.

The aim of the present study was to elucidate the association between excessive chronic iodine exposure and the risk of developing papillary thyroid carcinoma (PTC). The demographic information and pathological characteristics of patients with thyroid nodules were retrieved from medical records at The Second Hospital of Shandong University. A fasting urine specimen was collected, and creatinine and urinary iodine concentration (UIC) were determined. The water iodine data from the domicile districts of these patients were collated from published reports. The results revealed that almost half of the patients with PTC (44.3%) also exhibited a high UIC (≥300 µg/l). Multivariate analysis revealed that the adjusted odds ratio for high UIC was 3.987 (95% CI: 1.355-11.736) and the adjusted area under the receiver operating characteristic curve was 0.776 (95% CI: 0.687-0.864), which was associated with PTC risk in patients with thyroid nodules. Integrated ecological assessment of chronic iodine exposures demonstrated that >80% (81.4%) of the patients with PTC who also exhibited a high UIC were from historically non-iodine-deficient regions, and 66.7% of patients with PTC who resided in historically iodine-excessive regions were characterized by high UICs. Importantly, a high UIC was significantly associated with capsular invasion and extrathyroid metastasis (P<0.05). Moreover, self-matching results indicated that, in patients with PTC, there were no significant differences in UIC grading between the pre- and postoperative specimens. In conclusion, excessive chronic iodine exposure is significantly associated with the risk of PTC, which contributes to increased capsular invasion and extrathyroid metastases. However, further research is required to validate these findings and to elucidate the potential molecular mechanisms involved.

Stable Iodine Nutrition During Two Decades of Continuous Universal Salt Iodisation in Sri Lanka.

Universal salt iodisation (USI) was introduced in Sri Lanka in 1995. Since then, four national iodine surveys have assessed the iodine nutrition status of the population. We retrospectively reviewed median urine iodine concentration (mUIC) and goitre prevalence in 16,910 schoolchildren (6-12 years) in all nine provinces of Sri Lanka, the mUIC of pregnant women, drinking-water iodine level, and the percentage of households consuming adequately (15 mg/kg) iodised salt (household salt iodine, HHIS). The mUIC of schoolchildren increased from 145.3 µg/L (interquartile range (IQR) = 84.6-240.4) in 2000 to 232.5 µg/L (IQR = 159.3-315.8) in 2016, but stayed within recommended levels. Some regional variability in mUIC was observed (178.8 and 297.3 µg/L in 2016). There was positive association between mUIC in schoolchildren and water iodine concentration. Goitre prevalence to palpation was a significantly reduced from 18.6% to 2.1% (p < 0.05). In pregnant women, median UIC increased in each trimester (102.3 (61.7-147.1); 217.5 (115.6-313.0); 273.1 (228.9-337.6) µg/L (p = 0.000)). We conclude that the introduction and maintenance of a continuous and consistent USI programme has been a success in Sri Lanka. In order to sustain the programme, it is important to retain monitoring of iodine status while tracking salt-consumption patterns to adjust the recommended iodine content of edible salt.

[Iodine nutritional status and intake levels in adult from different water iodine content areas of Xinjiang Uygur Autonomous Region in 2017].

OBJECTIVE: To understand the iodine nutrition status of adults in Xinjiang Uygur Autonomous Region under the effective control of iodine deficiency disease. METHODS: Using stratified cluster random sampling method, in the district to determine water iodine median<10 µg/L and ≥10 µg/L of urban and rural areas, a total of 10 survey points, deals from the collecting water deals of extracting water iodine content detection. Adults over 18 years old were randomly selected from 30 households at each survey site to carry out a survey on dietary iodine intake, and the contents of dietary salt iodine and adult urine iodine were tested. RESULTS: The median iodine content in water in Xinjiang Uygur Autonomous Region was 4. 4(2. 3, 13. 6)µg/L. The median iodine content of household salt was 27(24, 30) mg/kg. The median urinary iodine content in adults was 168(103, 259)µg/L. The average dietary iodine intake of adults in the region was 312 µg/d. CONCLUSION: The water iodine content in the environment outside Xinjiang Uygur Autonomous Region is relatively low, and the iodine nutritional status and dietary iodine intake of adults are generally at the appropriate level. However, urban adults with relatively low water iodine content and good economic status have a higher risk of iodine deficiency. Iodized salt is the main source of dietary iodine for adults in Xinjiang Uygur Autonomous Region. Adults in poorer rural and urban areas rely more heavily on iodized salt.

Stopping the supply of iodized salt alone is not enough to make iodine nutrition suitable for children in higher water iodine areas: A cross-sectional study in northern China.

BACKGROUND: For the sake of children's health, iodized salt supply has been stopped in many areas with excessive iodine in the drinking water, but children's iodine nutrition status and thyroid function after terminating the iodized salt supply is unknown. Objective We assessed the iodine nutrition, thyroid function and influencing factors for thyroid abnormalities in children from areas with different concentrations of water iodine; the supply of iodized salt has been stopped in high water iodine areas. This study aimed to evaluate whether the strategy of stopping the supplies of iodized salt alone is enough to avoid thyroid dysfunction in all areas with excess water iodine while still meeting the iodine nutrition needs of children. METHODS: A cross-sectional study was conducted in children from four areas with different drinking water iodine concentrations in Tianjin, China. The drinking water samplings and spot urine samples were collected to estimate the external and internal iodine exposure levels. The thyroid volume was measured, and blood samples were collected to assess thyroid function. Logistic regression analysis was used to analyze risk factors for thyroid abnormalities. A dietary survey was conducted to determine the sources of iodine nutrition among the areas with different iodine concentrations in the drinking water. RESULTS: In the area with a drinking water iodine concentration ≥300 µg/L, the median urinary iodine concentration (UIC) in children was 476.30 (332.20-639.30) µg/L, which was higher than that in other groups (all P < 0.05), and the prevalence of thyroid nodules and the thyroid goiter rate were higher than those in the <100 µg/L, 100-150 µg/L and 150-300 µg/L areas (all P < 0.01). Binary logistic regression analysis indicated that the risk of thyroid abnormalities was significantly increased in the UIC 200-299 µg/L group (OR: 4.534; 95% CI: 1.565, 13.135; bootstrapped 95% CI: 1.689, 21.206, P = 0.004) and in the UIC ≥ 300 µg/L group (OR: 6.962; 95% CI: 2.490, 19.460; bootstrapped 95% CI: 2.838, 32.570, P = 0.001) compared to the 100-199 µg/L group. The iodine contribution rates from water in areas with water iodine concentrations ≥300 µg/L are up to 63.04%. CONCLUSIONS: After termination of the iodized salt supply, the level of iodine nutrition of children in the area with drinking water iodine concentrations ≥300 µg/L is still excessive. The water source needs to be replaced in this area. In the area with a water iodine concentration of 150-300 µg/L, it is proposed that stopping the supply of iodized salt is sufficient to achieve the proper iodine nutrition status in children.

Association between chronic exposure to different water iodine and thyroid cancer: A retrospective study from 1995 to 2014.

The controversy that iodine intake may increase the risk of thyroid cancer has heightened over the past twenty years. In this retrospective study, we mainly analyzed the association between water iodine and thyroid cancer and discussed the possible cause of the increase in thyroid cancer. This study was supported by three hospitals in areas with different water iodine concentration. 5574 patients with thyroid disease were recruited, of which 1429 patients had been diagnosed with thyroid cancer. These samples collectively were used to analyze the relationship of incidence and prevalence associated with water iodine. In addition, the ratio of maximum tumor diameter was analyzed. By analyzing the proportion of patients with thyroid cancer in thyroid diseases, we found a decrease in the proportion of thyroid cancer with increasing water iodine (P<0.0001). In addition, there was no significant correlation between the median water iodine and the prevalence of thyroid cancer, including papillary thyroid cancer (P>0.05). Meanwhile, the 5years' cumulative incidence of thyroid cancer increased with years (P<0.01). Comparing Cao county and Shan county, which are areas with high water iodine, to adequate iodine area such as in Mudan district, an increasing incidence is observed in 2010-2014 in Mudan district. Again, we observed a significant increase in the proportion of thyroid cancer with tumor size <1cm (P<0.01). Therefore, we concluded that cause(s) of increase in thyroid cancer may be ascribed to the sensitive diagnostic techniques and the improvement of living condition, but not water iodine.