Assessment of Individual and Mixed Effects of Six Minerals on Thyroid Hormones in Chinese Pregnant Women.

The biosynthesis of thyroid hormones is essential for brain and neurological development. It requires iodine as a key component but is also influenced by other nutrients. Evidence for the combined nutrient status in relation to thyroid hormones during pregnancy is limited. We aimed to investigate the joint associations of iodine, selenium, zinc, calcium, magnesium and iron with maternal thyroid functions in 489 pregnant women from Hangzhou, China. Serum levels of six essential minerals and thyroid function parameters were measured during the first antenatal visit. Linear regression, quantile g-computation and Bayesian kernel machine regression were used to explore the individual and joint relationships between the six minerals and thyroid hormones. Linear regression analyses revealed that calcium was positively associated with free triiodothyronine (FT3). Zinc was positively associated with free thyroxine (FT4). Iodine was negatively associated with thyroid-stimulating hormone (TSH) and positively associated with FT3 and FT4. The quantile g-computation and BKMR models indicated that the joint nutrient concentration was negatively associated with TSH and positively associated with FT3 and FT4. Among the six minerals, iodine contributed most to thyroid function. The findings suggested that maintaining the appropriate concentration of minerals, either as individuals or a mixture, is important for thyroid health during pregnancy.

Long-term impact of prophylactic central neck dissection in non-invasive classic papillary thyroid carcinoma.

BACKGROUND: The utilization of prophylactic central neck dissection (pCND) in cases of non-invasive clinical node-negative (cN0) papillary thyroid carcinoma (PTC) remains a topic of debate, with a dearth of long-term evidence. MATERIALS AND METHODS: We retrospectively reviewed 1181 cN0 PTC patients from 1997 to 2011. Of these, 641 underwent pCND (pCND + group) and 540 did not (pCND-group). Propensity score matching (PSM) was used to identify similar patients. Event-free survival and long-term complications including permanent hyperparathyroidism and permanent recurrent laryngeal nerve (RLN) paralysis were analyzed after PSM. RESULTS: The pCND + group had more aggressive characteristics. In the matched cohort after PSM, the 5-year, 10-year, and 15-year EFS rates were 98.9 %, 98.2 %, and 97.1 % for the pCND + group, and 97.7 %, 97.1 %, and 97.1 % for the pCND-group, respectively. There was no statistically significant difference in EFS rates between the two groups (Log Rank P = 0.38). There was no statistically significant difference in the incidence of permanent hyperparathyroidism (3.3 % vs. 1.5 %, P = 0.08) and permanent RLN paralysis (1.7 % vs. 0.9 %, P = 0.13) between the pCND+ and pCND- groups. CONCLUSION: Our study, with a median follow-up duration of 107 months, indicates that pCND does not lead to a significant reduction in nodal recurrence among non-invasive cN0 PTC patients.

Thyroglobulin as a Sensitive Biomarker of Iodine Status in Mildly and Moderately Iodine-Deficient Pregnant Women.

Pregnant women are more susceptible to iodine deficiency. However, there are limitations in existing indicators for the evaluation of iodine nutrition in pregnant women. The study aimed to explore whether thyroglobulin (Tg) can be used as a more sensitive biomarker for pregnant women with mild and moderate iodine deficiency. A repeated-measure study was conducted among 1332 pregnant women in Zhejiang Province, China. Serum and urine specimens were collected at a mean of 10, 17, and 32 weeks of pregnancy, respectively; thyroid-stimulating hormone (TSH), Tg, and urinary iodine concentrations were measured. Linear mixed effects models were used to determine the associations between interaction of iodine concentrations and increasing gestation week and TSH and Tg, where participants were divided by urinary iodine concentration (UIC). The median Tg concentration was 11.56, 11.45, and 12.43 µg/L in the first, second, and third trimesters, respectively. After controlling the covariates, the interaction effects between the iodine status and gestation week were significant for both TSH and Tg (p = 0.038 and p = 0.007, respectively). TSH increased with the week of gestation in both iodine concentration groups. Tg increased with advancing pregnancy in the iodine-deficient group whereas it did not in the iodine-sufficient group. There was no significant variation in TSH at each trimester, and Tg was higher in the iodine-deficient group than in the iodine-sufficient group. Tg may be a more sensitive iodine status biomarker than TSH for pregnant women with mild-to-moderate iodine insufficiency.

Dopant-Matrix Afterglow Systems: Manipulation of Room-Temperature Phosphorescence/Thermally Activated Delayed Fluorescence Afterglow Mechanism via Mismatch/Match of Intermolecular Charge Transfer between Dopants and Matrices.

Dopant-matrix organic afterglow materials exhibit ease of fabrication and intriguing functions in diverse fields. However, a deep and comprehensive understanding of their photophysical behaviors remains elusive. Here we report manipulation of a room-temperature phosphorescence/thermally activated delayed fluorescence (RTP/TADF) afterglow mechanism via the mismatch/match of intermolecular charge transfer between dopants and matrices. When dispersed in inert crystalline matrices, the luminescent dopants show RTP lifetimes up to 2 s. Interestingly, when suitable organic matrices are selected, the resultant dopant-matrix materials display a TADF-type afterglow under ambient conditions due to the formation of dopant-matrix intermolecular charge transfer complexes. Detailed studies reveal that reverse intersystem crossing from dopants' T1 states to charge transfer complexes' S1 states, which features a moderate kRISC of 101-102 s-1, is responsible for the emergence of a TADF-type organic afterglow in rigid crystalline matrices. Such less reported delicate photophysics reveals a new aspect of the excited state property in dopant-matrix afterglow systems.

The Dose-Response Effect of Fluoride Exposure on the Gut Microbiome and Its Functional Pathways in Rats.

Metabolic activities within the gut microbiome are intimately linked to human health and disease, especially within the context of environmental exposure and its potential ramifications. Perturbations within this microbiome, termed "gut microbiome perturbations", have emerged as plausible intermediaries in the onset or exacerbation of diseases following environmental chemical exposures, with fluoride being a compound of particular concern. Despite the well-documented adverse impacts of excessive fluoride on various human physiological systems-ranging from skeletal to neurological-the nuanced dynamics between fluoride exposure, the gut microbiome, and the resulting dose-response relationship remains a scientific enigma. Leveraging the precision of 16S rRNA high-throughput sequencing, this study meticulously examines the ramifications of diverse fluoride concentrations on the gut microbiome's composition and functional capabilities within Wistar rats. Our findings indicate a profound shift in the intestinal microbial composition following fluoride exposure, marked by a dose-dependent modulation in the abundance of key genera, including Pelagibacterium, Bilophila, Turicibacter, and Roseburia. Moreover, discernible alterations were observed in critical functional and metabolic pathways of the microbiome, such as D-lyxose ketol-isomerase and DNA polymerase III subunit gamma/tau, underscoring the broad-reaching implications of fluoride exposure. Intriguingly, correlation analyses elucidated strong associations between specific bacterial co-abundance groups (CAGs) and these shifted metabolic pathways. In essence, fluoride exposure not only perturbs the compositional equilibrium of the gut microbiota but also instigates profound shifts in its metabolic landscape. These intricate alterations may provide a mechanistic foundation for understanding fluoride's potential toxicological effects mediated via gut microbiome modulation.

Serum Iodine as a Potential Individual Iodine Status Biomarker: A Cohort Study of Mild Iodine Deficient Pregnant Women in China.

Iodine deficiency during pregnancy is a widespread public health concern, but indicators and methods for assessing iodine nutritional status are lacking. Serum iodine concentration (SIC) is an important iodine metabolism biomarker and can, to some extent, predict the risk of thyroid diseases, making it a potential biomarker for assessing individual iodine nutrition levels. Our study aimed to analyze the relationship between SIC and thyroid function in a cohort of mild iodine deficient pregnant women in China in order to explore the potential of SIC as a biomarker of individual iodine status in pregnancy. A total of 1540 early pregnant women (gestation < 10 weeks) aged 18 to 45 years old were included in the final study from a Zhejiang multicenter population-based mother and child cohort. Repeated measures of SIC, urinary iodine concentration (UIC), and thyroid function were taken at approximately 10, 17, and 32 weeks of gestation. The SIC was statistically correlated with all thyroid function indexes in the first trimester, and a very strong positive correlation with FT4 over three trimesters (r = 0.449, 0.550, and 0.544, respectively). Pregnant women with an SIC < 72.4 µg/L were at a higher risk of hypothyroxinemia (adjusted OR = 8.911, 95% CI = 5.141-15.447) and iodine deficiency (adjusted OR = 1.244, 95% CI = 1.031-1.502), while those with an SIC > 93.9 µg/L were at a higher risk of thyrotoxicosis (adjusted OR = 11.064, 95% CI = 6.324-19.357) and excessive iodine (adjusted OR = 11.064, 95% CI = 6.324-19.357). In contrast, the UIC was not correlated with thyroid diseases (p > 0.05). These findings indicate that the SIC is a potential biomarker for assessing individual iodine nutrition and thyroid dysfunction in pregnant women.

Deciphering Gut Microbiome Responses upon Microplastic Exposure via Integrating Metagenomics and Activity-Based Metabolomics.

Perturbations of the gut microbiome are often intertwined with the onset and development of diverse metabolic diseases. It has been suggested that gut microbiome perturbation could be a potential mechanism through which environmental chemical exposure induces or exacerbates human diseases. Microplastic pollution, an emerging environmental issue, has received ever increasing attention in recent years. However, interactions between microplastic exposure and the gut microbiota remain elusive. This study aimed to decipher the responses of the gut microbiome upon microplastic polystyrene (MP) exposure by integrating 16S rRNA high-throughput sequencing with metabolomic profiling techniques using a C57BL/6 mouse model. The results indicated that MP exposure significantly perturbed aspects of the gut microbiota, including its composition, diversity, and functional pathways that are involved in xenobiotic metabolism. A distinct metabolite profile was observed in mice with MP exposure, which probably resulted from changes in gut bacterial composition. Specifically, untargeted metabolomics revealed that levels of metabolites associated with cholesterol metabolism, primary and secondary bile acid biosynthesis, and taurine and hypotaurine metabolism were changed significantly. Targeted approaches indicated significant perturbation with respect to the levels of short-chain fatty acids derived from the gut microbiota. This study can provide evidence for the missing link in understanding the mechanisms behind the toxic effects of microplastics.

Dietary Administration of Black Raspberries and Arsenic Exposure: Changes in the Gut Microbiota and Its Functional Metabolites.

Mounting evidence has linked berries to a variety of health benefits. We previously reported that administration of a diet rich in black raspberries (BRBs) impacted arsenic (As) biotransformation and reduced As-induced oxidative stress. To further characterize the role of the gut microbiota in BRB-mediated As toxicity, we utilized the dietary intervention of BRBs combined with a mouse model to demonstrate microbial changes by examining associated alterations in the gut microbiota, especially its functional metabolites. Results showed that BRB consumption changed As-induced gut microbial alterations through restoring and modifying the gut microbiome, including its composition, functions and metabolites. A number of functional metabolites in addition to bacterial genera were significantly altered, which may be linked to the effects of BRBs on arsenic exposure. Results of the present study suggest functional interactions between dietary administration of black raspberries and As exposure through the lens of the gut microbiota, and modulation of the gut microbiota and its functional metabolites could contribute to effects of administration of BRBs on As toxicity.

Quantifying the associations of the air pollutant SO2 on outpatient visits for conjunctivitis in Hangzhou, China.

The aim of this study is to further investigate the single and cumulative associations of SO2 on outpatient visits for conjunctivitis. Data from outpatient visits, air pollutants, and meteorology was collected by the Eye Center of the Second Affiliated Hospital of the Zhejiang University School of Medicine, the Environmental Protection Department of Zhejiang Province, and the Meteorological Administration of Zhejiang Province from July 1, 2014, to November 30, 2019. A Poisson generalized linear regression model (PGLM), combined with a distributed lag nonlinear model (DLNM), was employed to analyze the association between SO2 and outpatient visits for conjunctivitis using PM2.5 and NO2 as covariates. Of the 539,649 outpatients for conjunctivitis recruited for analysis, 58.1% were female. Obvious single associations of SO2 were observed in outpatient visits for conjunctivitis, which is consistent with our previous results using a time-stratified case crossover design. A delay in the associations of SO2 on outpatient visits for conjunctivitis was further confirmed, with the longest lag being 12 days. The strongest lag effect was found at lag 0-11 with RR95th vs 25th = 1.30 (1.24, 1.37), and RR90h vs 25th = 1.23 (1.18, 1.28). Furthermore, the results showed that old people may be more sensitive to the associations of SO2 than adults and the younger ones. Our study provides the first evidence that outpatient visits for conjunctivitis are positively associated with both single and cumulative air pollutant SO2 exposure, suggesting that people especially elders had better to decrease outdoor activities when the SO2 concentration is above safe level.

Effects of iodine supplementation during pregnancy on maternal and offspring health: a review / 预防医学

@#Iodine is an essential nutrient required for thyroid hormone synthesis and human growth and development. Iodine requirements increase substantially during pregnancy, and insufficient iodine intake may affect the health of pregnant women, and fetal growth and development. Iodized salt-based iodine supplementation is effective to improve maternal iodine levels, reduce risk of thyroid dysfunctions, and plays a vital role in improvements of offspring growth and development and prevention of intellectual disability. However, excessive iodine supplementation during pregnancy may affect maternal thyroid functions and the nerve development of offspring. Precise and personalized iodine supplementation schemes are therefore required tailored to local iodine deficiency degree and pregnant women's individual iodine status. This review summarizes the advances in the impact of iodine supplementation during pregnancy on maternal and offspring health, so as to provide insights into the guidance of iodine supplementation during pregnancy.

The effects of temperature variability on mortality in patients with chronic obstructive pulmonary disease: a time-series analysis in Hangzhou, China.

Chronic obstructive pulmonary disease (COPD) is a leading cause of death in people aged over 60 years old. Research has been reported that ambient temperature and diurnal temperature range (DTR), as representative indices of temperature variability, are contributors to the development and exacerbation of COPD. However, few studies are available in Chinese population. In this study, we aimed to assess the associations of temperature variability on COPD mortality in a fast developing city in China. Using the mortality surveillance system, we obtained a total of 7,863 deaths attributed to COPD from 2014 to 2016. Quasi-Poisson generalized linear regression with distributed lag non-linear model was applied to explore the associations between temperature variability and COPD deaths, after controlling for the potential confounders, including relative humidity, day of week, public holiday, and long-term trend. A J-shaped association of DTR and a reversely J-shaped association of temperature for COPD mortality were observed. Risk estimates showed that the relative risks (RRs) of COPD mortality with extreme high DTR at lag 0 and 0-7 days were 1.045 (95% CI: 0.949-1.151) and 1.460 (95% CI: 1.118-1.908), and the extreme high temperature at lag 0 and 0-7 days were 1.090 (95% CI: 0.945-1.256) and 1.352 (95% CI: 1.163-1.572). Our findings suggest that short-term exposure to extreme temperature was associated with mortality for COPD in Hangzhou. The evidence has implications for policy decision-making and targeted interventions.

The Effects of Physical Activity and Sedentary Behaviors on Overweight and Obesity among Boys may Differ from those among Girls in China: An Open Cohort Study.

BACKGROUND: Childhood overweight and obesity are increasing steadily in China, yet few studies have focused on exploring the risk factors associated with sex differences. OBJECTIVES: We tested the hypothesis that the effects of physical activity and sedentary behaviors on overweight and obesity differ between boys and girls. METHODS: We used data collected from 4520 children and adolescents aged 6-18 y from 2004 to 2015 in an ongoing open-cohort study, the China Health and Nutrition Survey, to explore the effects of physical activity and sedentary behaviors on the risk of overweight and obesity in Chinese children and adolescents. We collected detailed information on physical activity and sedentary behavior along with dietary data, and we measured height and weight with standardized methods. We used random-effects logistic regression models to analyze the associations between total physical activity and sedentary behavior and overweight and obesity. RESULTS: The effects of sedentary behaviors and vigorous physical activity were only significant among girls. Vigorous physical activity decreased the risk of overweight and obesity by 63% (OR: 0.37; 95% CI: 0.20, 0.67) among girls ages 6-11 y and by 54% (OR: 0.46; 95% CI: 0.25, 0.85) among girls ages 12-18 y. High sedentary-hour values increased the risk by 96% (OR: 1.96; 95% CI: 1.09, 3.54) among girls ages 12-18 y. None of the effects were significant among boys. CONCLUSION: Low physical activity and high sedentary time increase the risk of overweight and obesity, particularly among adolescent girls. The effects of physical activity and sedentary behaviors on overweight and obesity among boys may differ from those among girls. Sex effects should be taken into consideration when promoting physical activity. Whether this sex difference is a result of high male preferences in China that preclude many activities among boys or other factors requires further study.

Low Iodine Intake May Decrease Women's Fecundity: A Population-Based Cross-Sectional Study.

Salt iodization is one of the most cost-effective strategies to eliminate iodine deficiency disorders (IDD). However, China's dismantling of salt monopoly has reduced the availability of iodized salt in the susceptible population in pregnancy, which might cause IDD and have adverse health effects on both themselves and their offspring. The aim of our study was therefore to explore the association between IDD and women's reproductive health. This is a population-based cross-sectional study conducted in 2018 in Zhejiang Province, China. A total of 1653 pregnant women participated in this study. Median urinary iodine concentration (UIC) in the population was used to assess iodine intake. Cox regression analyses were used to estimate the association between iodine intake and time to pregnancy, which was indicated with fecundability ratio (FR) and 95% confidence interval (CI). The percentage of participants with iodine deficiency who had been waiting longer than 13 months to get pregnant (20%; median UIC 119.6 µg/L) was significantly higher than those with iodine sufficiency (14%; median UIC 147.1 µg/L). A significant decrease in fecundity was observed in participants with iodine deficiency (FR, 0.820; 95% CI, 0.725-0.929) than those with iodine sufficiency. These findings indicate the importance of ongoing monitoring of iodine nutrition in women of reproductive age. Keeping a safe and optimal level of iodine nutrition during pregnancy should be emphasized.

Association between outpatient visits for pterygium and air pollution in Hangzhou, China.

Air pollution could be a risk factor for the development of pterygium. This study aimed to investigate the potential associations between outpatient visits for pterygium and air pollutants. Using a time-stratified case-crossover design, the data of 3017 outpatients with pterygium visiting an eye center in Hangzhou, China, and the air pollution data of the Environmental Protection Department of Zhejiang Province between July 1, 2014, and November 30, 2019, were examined. The relationships between the air pollutants nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone, and fine particulate matter (PM) with median aerometric diameter <2.5 µm (PM2.5) and <10 µm (PM10) and outpatient visits for primary pterygium were assessed using single- and multiple-pollutant models. Significant associations between outpatient visits for pterygium and air pollutants (PM2.5, PM10, SO2, and NO2) were observed. Younger patients were found to be more sensitive to air pollution. Interestingly, the younger female patients with pterygium were more vulnerable to PM2.5 exposure during the warm season, while the younger male patients with pterygium were more sensitive to NO2 during the cold season. Significant effects were also observed between the pterygium outpatients and PM2.5 (odds ratio [OR] = 1.06, P = 0.02), PM10 (OR = 1.04, P = 0.01), and SO2 (OR = 1.26, P = 0.01) during the warm season, as well as NO2 (OR = 1.06, P = 0.01) during the cold season. Our study provides evidence that outpatient visits for pterygium are positively associated with increases in the air pollutants PM2.5, PM10, SO2, and NO2, revealing the important role of air pollution in the occurrence and development of pterygium.

Increasing mortality caused by chronic obstructive pulmonary disease (COPD) in relation with exposure to ambient fine particulate matters: an analysis in Southeastern China.

The objective of this study was to investigate the association between ambient particulate matters (PMs) and chronic obstructive pulmonary disease (COPD) mortality. generalized additive mixed model was employed to investigate the effects of ambient fine and coarse PMs on COPD mortality using 13,066 deaths from 2014 to 2016 among six cities in Zhejiang Province in Southeastern China. The daily average death count due to COPD was 3, varying from 1 to 7 among six cities. The daily 24-h mean concentrations were diverse among cities, from 29.7 to 56.8 µg/m3 for PM2.5, 16.7 to 30.3 µg/m3 for PM2.5-10, and 50.3 to 87.1 µg/m3 for PM10, respectively. The analysis showed that daily exposure to PM2.5 and PM10 was associated with increased mortality due to COPD and that weak effects were observed between PM2.5-10 and COPD mortality. Our results provided solid evidence that the fine particles in air pollution have stronger functions on adverse health effects other than coarser particles in Southeastern China, which may be considered as a potential clinic target in PM-associated COPD.

Elevated cadmium and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in residents living near electroplating industries.

This study aims to evaluate the body burdens of cadmium (Cd) associated with potential health impairment in residents living near electroplating industries. A total of 269 residents from exposure area and 106 from control area were recruited. We measured the blood and urinary Cd levels using an inductively coupled plasma mass spectrometer (ICP-MS); performed physical examinations; determined the urinary levels of ß2-microglobulin (ß2-MG), Nacetyl-ß-D-glucosaminidase (NAG), and 8-hydroxy-2'-deoxyguanosine (8-OHdG); and evaluated the associations between Cd and these biomarkers. Blood and urinary Cd levels in exposure group were statistically higher than in control group (1.712 vs. 1.159 µg/L; 1.980 vs. 1.740 µg/L, respectively, p < 0.05). Urinary ß2-MG and 8-OHdG levels in exposure group were also statistically higher (0.448 vs. 0.090 mg/L; 12.759 vs. 12.115 µg/L, respectively, p < 0.05), but urinary NAG levels showed no significant difference between the two groups (13.614 vs. 8.246 IU/L, p > 0.05). The proportion of abnormal nasal symptoms occurring in exposed subjects (88.8%) was much higher than in control subjects (78.2%, p < 0.05). Urinary Cd levels were positively correlated with blood Cd levels, urinary 8-OHdG, and NAG levels (r = 0.307, r = 0.185, r = 0.150, p < 0.05), but not correlated with urinary ß2-MG levels (p > 0.05). In conclusion, our study revealed that residents living in close proximity to electroplating industries had elevated body burdens of Cd levels, as well as slight renal dysfunction and DNA oxidation damage.

Geographical influences on thyroid abnormalities in adult population from iodine-replete regions: a cross-sectional study.

The studies on the increasing incidence of thyroid abnormalities are scarce. The aim of this current study was to ascertain the effects of geographical region on thyroid abnormalities under the context of universal salt iodization (USI). We randomly selected 1255 participants residing in inland and 1248 in coast, with the determination of urinary iodine concentration (UIC) and functional and morphological abnormalities of thyroid gland. The median UIC was significantly higher for the inland participants (188.5 µg/L) than the coastal participants (128.5 µg/L; p < 0.001), indicating iodine sufficiency in both populations according to the recommended assessment criteria by the World Health Organization. However, the spectrum of thyroid abnormalities varied between regions, with hypothyroidism prevalent in inland and thyroid nodules in coast. The associations between region and thyroid abnormalities via binary logistic regression models showed that the coastal participants were at a higher risk of total thyroid abnormalities than those from the inland (OR 1.216, 95% CI 1.020-1.449), after the adjustment of ten confounders (demographical characteristics, smoking status, metabolism syndrome, and hyperuricemia). These results indicated that further investigations of the adverse effects of hypothyroidism and thyroid nodules on health burden is urgently needed to sustain USI program.

Integrative Analysis of DNA Methylation and Gene Expression Identified Follicular Thyroid Cancer-Specific Diagnostic Biomarkers.

The diagnosis of follicular thyroid carcinoma (FTC) prior surgical resection remains a challenge, as routine screening methods, such as ultrasound or even FNAB, could not diagnose FTC preoperatively. Here, we performed an integrative analysis of DNA methylation and RNA array data from our own cohort (14 Follicular thyroid carcinoma vs 16 Benign thyroid lesion) to identify thyroid cancer-specific DNA methylation markers. We first identified differentially methylated and expressed genes and examined their correlations. Candidate DNA methylation sites were selected and further verified in validation set. Among all candidate methylation sites, cg06928209 was the most promising site as a molecular marker for early diagnosis, with a sensitivity of 90%, a specificity of 80% and an AUC of 0.77. Overall, our study demonstrates the potential use of methylation markers in FTC diagnosis and may boost the development of new epigenetic therapies.

The Effect of Iodine Status on the Risk of Thyroid Nodules: A Cross-Sectional Study in Zhejiang, China.

OBJECTIVE: The aim of this study was to explore whether iodine nutrition is associated with the risk of thyroid nodules among adult population in Zhejiang Province, China. METHODS: A cross-sectional study was conducted in the general population aged 18 years or older. A total of 2,710 subjects received physical examination, questionnaires, and thyroid ultrasonography. Urinary iodine concentration (UIC) and thyroid hormone levels were measured and documented for each subject. 4 multiple logistic regression models adjusted for other risk factors were applied to analyze the association between iodine nutrition and thyroid nodules. RESULTS: The prevalence of thyroid nodules was 15.5% among all adults. As indicated by all 4 models, subjects with UIC varying from 200 µg l-1 to 399 µg l-1 had lower risk of thyroid nodules compared with those with relatively low UIC (<100 µg l-1), with approximately 37-57 percent reduction in risk. Moreover, subjects with UIC between 100 and 199 µg l-1 had a decreased risk of thyroid nodules in model 1 and 2 (OR = 0.75, 95% CI, 0.58-0.97; OR = 0.75, 95% CI, 0.58-0.97, respectively). However, there was no significant difference of risk in thyroid nodules between subjects with high UIC (≥400 µg l-1) and low UIC (<100 µg l-1). Furthermore, intake of iodized salt was inversely associated with risk of thyroid nodules, with approximately 69-77 percent reduction in risk. CONCLUSION: The relationship between UIC and the risk of thyroid nodules is U-shaped. Consumption of noniodized salt is an independent risk factor of thyroid nodules.

Geographical influences on the iodine status in pregnant women, neonates, and school-age children in China.

BACKGROUND: Pregnant women, neonates, and school-age children are vulnerable to iodine deficiency. The iodine contents in the environment (drinking water and household salt for cooking) vary by geographical location in China. The aim of this study was to assess the iodine status in vulnerable groups from different geographical zones and analyze the iodine content in household salt and drinking water from these zones. METHODS: In coastal and inland regions of Zhejiang Province, China, samples of spot urine, drinking water, and household salt for cooking from both pregnant women and school-age children were determined for iodine concentration between 2017 and 2018. Thyroid-stimulating hormone (TSH) levels from neonates born between 2014 and 2015 were acquired from the Newborns Screening Information System. The iodine status of the vulnerable populations was assessed according to the criteria recommended by the World Health Organization. RESULTS: The median UIC of pregnant women was significantly lower in the coastal region (113.0 µg/L) than the inland region (134.9 µg/L; p < 0.001). The median UICs of pregnant women from these two regions were below the lower optimal iodine cutoff level of 150 µg/L. The percentage of neonates with elevated TSH (> 5 mIU/L) was significantly higher in the coastal region (15.8%) than the inland region (10.5%; p < 0.001). The percentage of neonates with elevated TSH from each region decreased within the range of mild iodine deficiency of 3-19.9%. The median UIC of the coastal school-age children was 156.0 µg/L, and the median UIC of inland children was 181.5 µg/L. Both medians fell within the recommended optimal iodine range of 100-299 µg/L. The iodine concentrations in drinking water varied from 1.0 µg/L in the inland region to 2.0 µg/L in the coastal region. The proportion of households that consumed iodized salt was lower in the coastal region (nearly 65%) than the inland region (approximately 95%). CONCLUSIONS: In these two regions with low iodine contents in drinking water, both pregnant women and neonates were iodine-deficient, although school-age children were iodine-sufficient. Urgent efforts are needed to improve the iodine status of pregnant women and neonates.