Iodine Metabolism in Urine and Breast Milk among Lactating Women with Adequate Iodine.

BACKGROUND: In lactating women, iodine metabolism is regulated and maintained by the kidneys and mammary glands. Limited research exists on how iodine absorbed by lactating women is distributed between the kidneys and breasts. OBJECTIVES: This study aimed to accurately evaluate the total iodine intake (TII), urinary iodine excretion (UIE), and breast milk iodine excretion (BMIE) in lactating women and explore the relationship between TII and total iodine excretion (TIE). METHODS: A 7-d iodine metabolism study was conducted on 41 lactating women with a mean age of 30 y in Yuncheng and Gaoqing, China, from December 2021 to August 2023. TII and TIE were calculated by measuring the iodine content in food, water, 24-h urine, feces, and breast milk. The urinary iodine excretion rate (UIER), breast milk iodine excretion rate (BMIER), and partitioning of iodine excretion between urine and breast milk were determined. RESULTS: Iodine metabolism studies were performed for 285 d. The median TII and TIE values were 255 and 263 µg/d, respectively. With an increase in TII, UIER, and BMIER, the UIE and BMIE to TII ratio exhibited a downward trend. The median UIER, BMIER, and proportion of iodine excreted in urine and breast milk were 51.5%, 38.5%, 52%, and 37%, respectively. When the TII was <120 µg/d, the BMIER decreased with the increase of the TII (ß: -0.90; 95% confidence interval: -1.08, -0.72). CONCLUSIONS: When maternal iodine intake is low, the proportion in breast milk increases, ensuring sufficient iodine nutrition for infants. In addition, the UIE of lactating women with adequate iodine concentrations is higher than their BMIE. This study was registered at clinicaltrials.gov as NCT04492657.

Salivary iodine concentration in pregnant women and its association with iodine status and thyroid function.

PURPOSE: There have been no reports on the application of salivary iodine concentration (SIC) in evaluating iodine nutrition in pregnant women. This study aimed to clarify the relationship between SIC and indicators of iodine nutritional status and thyroid function during pregnancy, to investigate whether salivary iodine can be applied to the evaluation of iodine nutritional status in pregnant women, and to provide a reference basis for establishing a normal range of salivary iodine values during pregnancy. METHODS: Pregnant women were enrolled in the Department of Obstetrics, the people's hospital of Yuncheng Country, Shandong Province, from July 2021 to December 2022, using random cluster sampling. Saliva, urine, and blood samples were collected from pregnant women to assess iodine nutritional status, and venous blood was collected to determine thyroid function. RESULTS: A total of 609 pregnant women were included in this study. The median spot urinary iodine concentration (SUIC) was 261 µg/L. The median SIC was 297 µg/L. SIC was positively correlated with SUIC (r = 0.46, P < 0.0001), 24-h UIC (r = 0.30, P < 0.0001), 24-h urinary iodine excretion (24-h UIE) (r = 0.41, P < 0.0001), and estimated iodine intake (EII) (r = 0.52, P < 0.0001). After adjusting for confounders, there was a weak correlation between SIC and serum total iodine and serum non-protein-bound iodine (P = 0.02, P = 0.04, respectively). Pregnant women with a SIC < 176 µg/L had a higher risk of insufficient iodine status (OR = 2.07, 95% CI 1.35-3.19) and thyroid dysfunction (OR = 2.71, 95% CI 1.18-6.21) compared to those with higher SIC. Those having SIC > 529 µg/L were more likely to have excessive iodine status (OR = 2.82, 95% CI 1.81-4.38) and thyroid dysfunction (OR = 3.04, 95% CI 1.36-6.78) than those with lower SIC values. CONCLUSION: SIC is associated with urinary iodine concentration and thyroid function in pregnant women. SIC < 176 µg/L was associated with an increased risk for iodine deficiency and hypothyroxinemia, while SIC > 529 µg/L was related to excess and thyrotoxicosis. SIC can be used as a reference indicator for evaluating the iodine nutrition status of pregnant women, but it needs further investigation and verification. TRIAL REGISTRATION: NCT04492657(Aug 9, 2022).

Study of iodine transport and thyroid hormone levels in the human placenta under different iodine nutritional status.

Iodine and thyroid hormones (TH) transport in the placenta are essential for fetal growth and development, but there is little research focus on the human placenta. The research aimed to investigate iodine and TH transport mechanisms in the human placenta. The placenta was collected from sixty healthy pregnant women. Urinary iodine concentration (UIC), serum iodine concentration (SIC), placenta iodine storage (PIS) and the concentration of serum and placenta TH were examined. Five pregnant women were selected as insufficient intake (II), adequate intake (AI) and above requirements intake (ARI) groups. Localisation/expression of placental sodium/iodide symporter (NIS) and Pendrin were also studied. Results showed that PIS positively correlated with the UIC (R = 0·58, P < 0·001) and SIC (R = 0·55, P < 0·001), and PIS was higher in the ARI group than that in the AI group (P = 0·017). NIS in the ARI group was higher than that in the AI group on the maternal side of the placenta (P < 0·05). NIS in the II group was higher than that in the AI group on the fetal side (P < 0·05). In the II group, NIS on the fetal side was higher than on the maternal side (P < 0·05). Pendrin was higher in the II group than in the AI group on the maternal side (P < 0·05). Free triiodothyronine (r = 0·44, P = 0·0067) and thyroid-stimulating hormone (r = 0·75, P < 0·001) between maternal and fetal side is positively correlated. This study suggests that maternal iodine intake changes the expression of NIS and Pendrin, thereby affecting PIS. Serum TH levels were not correlated with placental TH levels.

The association between thyroid-stimulating hormone and thyroid nodules, goiter and thyroid antibody positivity.

Background: The relationship between normal thyroid-stimulating hormone (TSH) levels and thyroid disease in adults remains controversial. This study aimed to investigate the correlation between serum TSH levels, particularly those falling within the normal range, and thyroid diseases in Chinese adults, including thyroid nodules (TN), goiter (GR), and thyroid antibody positivity. Materials and methods: This research was a cross-sectional study conducted in an adult population in Tianjin, China. Thyroid volume (Tvol) and TN were assessed using thyroid ultrasonography. Fasting venous blood and spot urine samples were collected to evaluate thyroid function and iodine status. Results: A total of 2460 subjects participated in the survey. The prevalence of thyroid dysfunction was 9.76%, and abnormal TSH levels were found to potentially increase the risk of GR and thyroid antibody positivity in adults. A total of 2220 subjects with TSH within the normal reference range were included in the further study. In these patients, Tvol decreased as TSH levels increased, in both men and women (P < 0.0001). Low TSH levels (0.27-1.41 IU/mL) were identified as a risk factor for TN (odds ratio [OR], 1.46; 95% CI: 1.14-1.87) and GR (OR 5.90, 95% CI 2.27-15.3). Upon stratification by sex and age, the risk of TN was found to be higher in women and elderly individuals (≥60 years old), while the risk of GR was found to be higher in men and younger individuals (<60 years old). High TSH levels (2.55-4.2 IU/mL) were identified as a risk factor for thyroid antibody positivity (OR, 1.53; 95% CI: 1.11-2.10). Men and younger individuals with high TSH levels exhibited a higher risk of thyroid antibody positivity. Conclusion: In adults with normal TSH levels, low TSH levels were associated with an increased risk of TN and GR, whereas high TSH levels were associated with thyroid antibody positivity. The research also suggests that adults whose TSH levels at upper or lower limits of the normal range should be reviewed regularly.

Iodine-specific food frequency questionnaire can evaluate iodine intakes of Chinese pregnant women.

Iodine is an essential trace element for the synthesis of thyroid hormones, which play an important role in growth and development, metabolism, and body organ function. There is no iodine-specific food frequency questionnaire (I-FFQ) for pregnant women in China. This study aimed to validate and optimize an I-FFQ. A total of 1802 pregnant women were included in this study. The iodine nutrition survey was performed using I-FFQ and 3-day estimated food diary (3DEFD). Seventy-one women of reproductive age repeated the I-FFQ twice to assess for FFQ reproducibility. Further optimization of the I-FFQ was accomplished by integrating iodine contributions to simplified questionnaire items. Correlation and Bland-Altman analyses were used to verify the consistency of I-FFQ with 3DEFD, as well as the stability and feasibility of I-FFQ optimization. The I-FFQ and 3DEFD had a strong correlation (R = 0.76, P < .001) and agreement (Kappa = 0.731, P < .001). A Bland-Altman plot showed that 5.1% of participants exceeded the limit of agreement. Nonpregnant women of reproductive age completed the I-FFQ twice, and the results had a strong correlation (R = 0.72, P < .001). A Bland-Altman analysis showed that 5.6% of individuals were located outside the limit of agreement. The consistency of I-FFQ before and after optimization was good (Kappa = 0.982, P < .001). Therefore, I-FFQ could be used as a valid tool to estimate iodine intake among Chinese pregnant women. The optimized I-FFQ could shorten survey time without affecting its accuracy.

The Relationship Between Iodine Excess and Thyroid Function During Pregnancy and Infantile Neurodevelopment at 18-24 Months.

BACKGROUND: Thyroid disease is a prevalent condition during pregnancy, and excessive iodine intake can lead to changes in thyroid function. However, research on the relationship between maternal iodine excess, thyroid hormones during pregnancy, and infantile neurodevelopment is limited. OBJECTIVES: This study aimed to explore the relationship between maternal iodine excess and thyroid hormones during pregnancy and infantile neurodevelopment. The objective was to provide evidence to support and enhance the prevention of neurodevelopmental retardation in infants. METHODS: From 2016 to 2018, a prospective study was conducted from pregnancy to 18-24 mo postpartum. Maternal urinary iodine concentration (UIC), thyroid-stimulating hormone (TSH), total serum iodine (TSI), and nonprotein-bound serum iodine during pregnancy were determined. The Gesell Development Scale was used to assess neurodevelopment of infants aged 18-24 mo. The iodine status of pregnant females was divided into following 4 groups on the basis of the distribution of maternal UIC: <100 µg/L (moderate deficiency), 100-149 µg/L (mild deficiency), 150-249 µg/L (sufficiency), and >250 µg/L (above requirement). RESULTS: Our study included 469 mother-infant pairs. Compared with the maternal UIC of 150-249 µg/L during pregnancy, risk of adaptive developmental delay was increased in infants with maternal UIC ≥250 µg/L (OR: 2.38; 95% CI: 1.06, 5.35). Pregnant females with TSI >90th quantiles were more likely to have offspring with language developmental delay than those with lower TSI in 10th-90th quantiles (OR: 3.06; 95% CI: 1.09, 8.58). Risk of fine motor developmental delay was increased in infants with maternal TSH ≥2.5 mIU/L during pregnancy (OR: 4.32; 95% CI: 1.43, 13.0). CONCLUSIONS: Maternal iodine nutritional status above requirement (UIC ≥250 µg/L or TSI >90th quantiles) during pregnancy negatively affects infantile neurodevelopment. Maternal TSH ≥2.5 mIU/L during pregnancy was an independent risk factor for infantile neurodevelopment. This trial was registered at clinicaltrials.gov as NCT03710148.

Clinical characteristics of patients with prenatal hydronephrosis in early postnatal period: a single center retrospective study.

BACKGROUND: The study aims to investigate the clinical characteristics of early postnatal period in children with prenatal hydronephrosis (HN) in our single center for 8 years. STUDY DESIGN: The clinical data of 1137 children with prenatal HN from 2012 to 2020 were retrospectively analyzed in our center. Variables of our study mainly included different malformations and urinary tract dilation (UTD) classification, and main outcomes were recurrent hospitalization, urinary tract infection (UTI), jaundice, and surgery. RESULTS: Among the 1137 children with prenatal HN in our center, 188 cases (16.5%) were followed-up in early postnatal period, and 110 cases (58.5%) were found malformations. The incidence of recurrent hospitalization (29.8%) and UTI (72.5%) were higher in malformation, but the incidence of jaundice (46.2%) was higher in non-malformation(P < 0.001). Furthermore, UTI and jaundice were higher in vesicoureteral reflux (VUR) than those in uretero-pelvic junction obstruction (UPJO) (P < 0.05). Meanwhile, Children with UTD P2 and UTD P3 were prone to recurrent UTI, but UTD P0 was prone to jaundice (P < 0.001). In addition, 30 cases (16.0%) of surgery were all with malformations, and the surgical rates of UTD P2 and UTD P3 were higher than those of UTD P0 and UTD P1 (P < 0.001). Lastly, we concluded that the first follow-up should be less than 7 days, the first assessment should be 2 months, and the follow up should be at least once every 3 months. CONCLUSION: Children with prenatal HN have been found many malformations in early postnatal period, and with high-grade UTD were more prone to recurrent UTI, even to surgery. So, prenatal HN with malformations and high-grade UTD should be followed up in early postnatal period regularly.

An Iodine Balance Study in Chinese School-age Children.

CONTEXT: Few iodine balance studies have been conducted in school-age children. OBJECTIVE: This study aimed to conduct an iodine balance study in school-age children. METHODS: We measured daily iodine intake, excretion, and retention for 3 consecutive days without any dietary interventions in school-age children. Linear mixed-effects models were used to fit the relationship between total iodine intake and iodine retention. RESULTS: 29 children aged 7-12 years (mean age 10.2 ± 1.4 years) with normal thyroid function and thyroid volume were recruited. The 0 balance value (iodine intake = iodine excretion, iodine retention = 0 µg/day) shifted with iodine intake in an iodine sufficient population. The 0 balance value for school-age children with an iodine intake of 235 (133, 401) µg/day is 164 µg/day. Children aged 7-12 years with iodine intake >400 µg/day were almost all in a positive iodine state. CONCLUSION: An iodine intake of 235 (133, 401) µg/day for children aged 7-10 years achieved a 0 balance value of 164 µg/day. Long-term iodine intake of >400 µg/day is not recommended.

Adverse Effects on the Thyroid of Chinese Pregnant Women Exposed to Long-Term Iodine Excess: Optimal and Safe Tolerable Upper Intake Levels of Iodine.

Ensuring optimal iodine nutrition in pregnant women is a global public health concern. However, there is no direct data on safe tolerable upper intake levels (ULs) for pregnant women. A cross-sectional study was performed to determine the ULs of pregnant women. A total of 744 pregnant women were enrolled in this study. The median (IQR) urinary iodine concentration (UIC) in pregnant women was 150.2 (87.6, 268.0) µg/L, and the urinary iodine excretion (UIE) over 24 h was 204.2 (116.0, 387.0) µg/day. Compared with those with a UIE figure of between 150-250 µg/day, the reference group, the prevalence of thyroid dysfunction was 5.7 times higher (95%CI: 1.7, 19.2) in pregnant women with a UIE figure of between 450-550 µg/day, and 3.9 times higher (95%CI: 1.5, 10.3) in pregnant women with a UIE figure of ≥550 µg/day. Compared with an estimated iodine intake (EII) of between 100-200 µg/day, the reference group, the prevalence of thyroid dysfunction was 4.3 times higher (95%CI: 1.3, 14.4) in pregnant women with a UIE figure of between 500-600 µg/day, and 3.6 times higher (95%CI: 1.5, 8.9) in pregnant women with UIE of ≥600 µg/day. In general, our cross-sectional study found that excessive iodine intake during pregnancy appears to directly increase the risk of thyroid dysfunction. Avoiding chronic iodine intakes of 500 µg/day or higher or having a UIE figure of ≥450 µg/day is recommended for pregnant women in China.

Iodine Intakes of <150 µg/day or >550 µg/day are Not Recommended during Pregnancy: A Balance Study.

BACKGROUND: Adequate iodine intake during pregnancy is critical for maintaining maternal and fetal thyroid function and development. There are only limited data from iodine-balance studies to inform iodine requirements during pregnancy. OBJECTIVES: This is an iodine-balance study conducted to explore the associations among iodine intake, excretion, and retention to provide information regarding iodine requirements during pregnancy. METHODS: A 7-d iodine-balance experiment enrolled 93 healthy pregnant Chinese women from Hebei, Tanjin, and Shandong. Duplicates of all foods and beverages consumed were systematically collected and measured for iodine content. Iodine excretion was measured by collecting 24-h urine and feces samples. Simple linear regression models were used to assess relationships between total iodine intake and iodine retention, whereas mixed effect models were used to assess the relationship between daily iodine intake and iodine retention. RESULTS: The mean ± SD age of participating pregnant women was 29 ± 2 y at a median 22 (IQR: 13-30) wk of gestation. The mean 7-d iodine retention was 43.0 ± 1060 µg/7 d. A negative iodine balance was present in 56% of women whereas 44% had a positive balance. Pregnant women with iodine intakes <150 µg/d were in negative balance whereas those with intakes >550 µg/d were in positive balance. The daily iodine intake at zero balance was 343 µg/d, which was higher in women from Shandong (492 µg/d) than in those from Hebei and Tianjin (202 µg/d). CONCLUSIONS: Iodine intake at zero balance determined in pregnant women with adequate iodine nutrition is 202 µg/d, and the calculated recommended nutrient intake (RNI) is 280 µg/d. Iodine intakes of <150 µg/d and >550 µg/d are not recommended during pregnancy. This trial was registered at clinicaltrials.gov as NCT03710148.

The simplified iodine-specific food frequency questionnaire can evaluate iodine intake in Chinese adults.

We hypothesized that an effective iodine-specific food frequency questionnaire (I-FFQ) simplification method could expand the application of the I-FFQ in evaluating long-term iodine intake. An adult I-FFQ was developed and was simplified by deleting food items with iodine contribution rates ≤0.1%, combining food items with similar species and iodine contribution rates, and calculating the iodine content of combined food by a weighted calculation method. A 3-day (3-d) diet diary tested the validity of the I-FFQ. We evaluated the relationship between iodine intake estimated using the I-FFQ and the urinary iodine to creatinine ratio, thyroid volume (Tvol), and thyroid function. The Kappa value was 0.62 for the original I-FFQ and the 3-d diet diary (P < .001), 0.78 for the short-version I-FFQ and the 3-d diet diary (P < .001), and 0.76 for the original I-FFQ and the short-version I-FFQ (P < .001). The mean difference before and after simplification was 27.1 µg/d. The Tvol was different between the I-FFQ groups and showed an upward trend (P for trend = .01). Tvol was higher in the 284 347 µg/d (ß = 0.72; 95% CI, 0.16-1.28; P = .01) groups after simplification. The I-FFQ is an effective method for evaluating iodine nutritional status in adults. After streamlining, the food items were reduced from 58 to 15, which shortened the investigation time while retaining evaluation efficiency; it is also easier to get the cooperation of the subjects and improve the availability of I-FFQ.

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.

Effects of maternal iodine nutritional status on neurodevelopmental and cognitive function of rat offspring.

Objectives: This study aimed to explore the effect of maternal iodine status on the brain development of offspring in rats. Since in human studies, the interference of environmental factors and other nutrients cannot be removed. Materials and methods: A total of 48 female Wistar rats were randomly divided into four groups: low iodine (LI), normal iodine (NI), 10-fold high iodine (10HI), and 50-fold high iodine (50HI). The rats were killed on the 15th day of pregnancy and lactation after collecting 24-h urine. The iodine concentration in 24-h urine, blood, and placenta of pregnant rats, and 24-h urine, milk, blood, and mammary glands of lactating rats was determined by inductively coupled plasma mass spectrometry. The thyroid hormone of pregnant and lactating rats was detected by chemiluminescence. The offspring were subjected to the Morris water maze on the 10th day after birth. Serum was collected to detect the thyroid hormone of offspring. The protein expression of neuroendocrine-specific protein (NSP)-A and brain-derived neurotrophic factor (BDNF) in the offspring brain were studied. Results: Iodine storage in the placenta during pregnancy and mammary glands during lactation was positively correlated with iodine intake, and iodine storage in the placenta and mammary glands in the 50HI group was significantly higher than that in the NI group (P = 0.045 and P = 0.040). Compared with the NI group, the offspring thyroid-stimulating hormone (TSH) level was significantly higher in the 10HI group (P = 0.046), and the FT4 level was significantly lower in the 50HI group (P = 0.032). The Morris water maze showed that LI and 50HI groups required longer time and distance to find the platform than the NI group (P < 0.001). The platform crossing numbers in the LI and 50HI groups decreased significantly (P < 0.001). The expression of NSP-A in offspring brain was lower in the 10HI and 50HI groups than in the NI group (P = 0.026 and P = 0,008). BDNF expression levels were significantly lower in the LI, 10HI, and 50HI groups than in the NI group (P < 0.001). Conclusion: Maternal iodine intake affects iodine storage in the placenta and lactating mammary gland, which in turn affects thyroid function and BDNF and NSP-A expression in the offspring.

Characteristics and predictors of breast milk iodine in exclusively breastfed infants: Results from a repeated-measures study of iodine metabolism.

Background: The iodine supply of exclusively breastfed infants entirely depends upon breast milk. Changes in breast milk iodine affect infants' iodine nutritional status. This study aimed to comprehensively assess the characteristics and predictors of breast milk iodine concentration (BMIC). Materials and methods: This 7-day iodine metabolism experiment was conducted in 25 exclusively breastfed mother-infant pairs. The duplicate portion method was used to measure the mother's daily iodine intake from foods and water, and maternal 24-h urine excretion was assessed. We recorded the number of breastfeeds per mother per day and collected breast milk samples before and after each feeding. Results: The median [quartile (Q)1-Q3 range] of BMIC was 115 (86.7, 172) µg/L. The BMIC before breastfeeding was generally higher than that after breastfeeding. Time-sequential analysis found that morning BMIC was most highly correlated with the prior day's iodine intake. Breast milk samples taken in the afternoon or after midnight are closer to the median level of BMIC throughout the day. The number of breast milk samples needed to estimate the iodine level with 95% CI within precision ranges of ± 20% was 83 for a population, 9 for an individual, and 2 for an individual's single day. Maternal total iodine intake (TII) and urine iodine were significantly associated with BMIC. 24-h urinary iodine excretion (24-h UIE) was found to be the best predictive indicator for the BMIC (ß = 0.71, 95% CI: 0.64, 0.79). Conclusion: BMIC is a constantly changing indicator and trended downward during each breastfeeding. Breast milk samples taken in the afternoon or after midnight are most representative. BMIC was significantly associated with recent iodine intake. Maternal 24-h UIE was the best predictor of BMIC.

[Cognition, behavior and demand of iodine nutrition in residents of North China Region from 2019 to 2020].

OBJECTIVE: To evaluate residents in North China cognition level of iodine nutrition and their intention to evaluate individual iodine status. METHODS: From February 2019 to June 2020, randomly selected six provinces and cities in north China and more than three cities or areas, then randomly selected local investigators and distributed questionnaires to urban and rural residents. The questionnaire was divided into three parts: basic information, iodine nutrition knowledge, iodine status evaluation demand and approaches. RESULTS: Finally, there are 740 questionnaires were included. The scores of iodine knowledge of the subjects were generally low, about 71.22% of the subjects with less than 6 points(full score of 12 points). Residents who did not know how to choose the type of salt accounted for 25.14%. Provinces and cities with low utilization rate of iodized salt(Tianjin, Shandong) had higher requirements for salt use guidance and iodine status evaluation. The awareness rate of the subjects to the harm of iodine deficiency was low(34.46%), especially the hazard to pregnant women and infants(7.57%, 4.59%). Subjects had a high demand for using wechat mini-program or kit to evaluate individual iodine nutrition(87.45%, 89.39%). CONCLUSION: At present, residents in North China have a low cognitive level of iodine nutrition, which lead to them the doubts when choosing salt types. The selection of iodized salt can be effectively guided by propagating iodine nutrition knowledge and promoting accurate iodine nutrition evaluation.

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.

Clinical Characteristics, In Silico Analysis, and Intervention of Neonatal-Onset Inflammatory Bowel Disease With Combined Immunodeficiency Caused by Novel TTC7A Variants.

We aimed to explore the genotypic and phenotypic characteristics of neonatal-onset inflammatory bowel disease (IBD) with combined immunodeficiency due to TTC7A mutation. We examined the clinical manifestations, imaging results, endoscopic and histological findings, interventions, and prognosis of a proband with neonatal-onset IBD and performed biochemical analyses, whole-exome sequencing (WES), and in silico analysis. Our proband developed severe early-onset diarrhea, malnutrition, electrolyte imbalance, dehydration, and recurrent infections after birth. Radiographic and ultrasonic images showed no specific manifestations. Endoscopic and histological examination revealed chronic inflammation. Immune function examination indicated immunodeficiency. WES identified compound heterozygous TTC7A mutations (c.2355+4A>G, c.643G>T) in the proband. In the expression analysis, no abnormal splicing in the TTC7A sequence was observed due to the c.2355+4A>G mutation; however, the mRNA expression was reduced. The proband's condition did not improve after treatment with methylprednisolone or leflunomide. The proband died when treatment was stopped at the age of 5 months and 19 days. Compound heterozygous mutations (c.2355+4A>G, c.643G>T) in the TTC7A gene are described and verified for the first time. Our report expands the phenotypic spectrum of TTC7A mutations and the genotypic spectrum of very early-onset IBD with combined immunodeficiency.

Exploration of the optimal range of urinary iodine concentration in Chinese pregnant women in mildly iodine-deficient and -sufficient areas.

PURPOSE: There is some uncertainty about the optimal ranges for urinary iodine concentration (UIC) during pregnancy. This study aimed to explore associations between maternal UIC and thyroid function in iodine sufficient and mildly iodine deficient areas. METHODS: It was a cross-sectional study in which 1461 healthy pregnant women were enrolled to collect their blood and urine samples during their routine antenatal care in Tianjin and Wuqiang, China. Wuqiang was a mildly iodine-deficient region, while Tianjin was iodine sufficient. UIC, free triiodothyronine (FT3), free thyroid hormone (FT4), thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), serum iodine concentration (SIC) including total serum iodine concentration (tSIC) and non-protein bound serum iodine concentration (nbSIC) were assessed during the routine antenatal care visits. RESULTS: The median UIC in pregnant women was 174 (113, 249) µg/L in Tianjin and 111 (63, 167) µg/L in Wuqiang, respectively. Compared with Tianjin, UIC, FT3 and TSH were lower, and FT4, tSIC, nbSIC, rates of TPOAb and TgAb positivity and the thyroid dysfunction rate (TDR) were higher in Wuqiang (P < 0.001). FT3, FT4, tSIC and nbSIC increased during pregnancy in Tianjin with increasing UIC, while only FT3 and nbSIC increased in Wuqiang (P < 0.05). In Tianjin, the TDR increased with UIC and peaked at UIC ≥ 500 µg/L (P = 0.002), while in Wuqiang, the TDR showed a weak "U-shaped" relationship with UIC and the rate was lowest with UIC 100-149 µg/L. CONCLUSIONS: In iodine-deficient areas, there was a lower TDR in pregnant women with UIC 100-149 µg/L. We suspected that the optimal UIC criteria recommended by WHO may be a little high for pregnant women in mild-to-moderate iodine-deficient countries.

New Reference Values for Thyroid Volume and a Comprehensive Assessment for Influencing Factors in Chinese Adults with Iodine Sufficiency.

OBJECTIVES: The reference values for thyroid volume (Tvol) determined by ultrasound require supportive data of normal Tvol from local iodine-sufficient populations. This study aimed to explore new reference values for Tvol in Chinese adults and comprehensively evaluate the factors associated with enlarged Tvol. METHODS: A cross-sectional study was conducted in Tianjin, China. Tvol was measured by ultrasound in adults with long-term iodine sufficiency. Blood and urine samples were collected to evaluate biochemical indexes, thyroid function, and iodine status. RESULTS: A total of 1,991 adults from the urban and suburban areas were analysed. The trend of Tvol increasing with age was observed in men under age 40 years and in women under age 52 years. In the quantile regression analyses, we found that body surface area (BSA) (ß = 7.22, 95% CI: 5.33, 9.12), thyroid-stimulating hormone (TSH) (ß = -1.48, 95% CI: -2.39, -0.57), thyroid nodules (TNs) (ß = 6.70, 95% CI: 2.19, 11.22), and metabolic syndrome (MetS) (ß = 1.40, 95% CI: 0.63, 2.17) had a strong effect on Tvol at higher percentiles in males. The dominant factors influencing Tvol were BSA (ß = 9.64, 95% CI: 2.66, 16.61), TSH (ß = -0.78, 95% CI: -1.16, -0.39), and TNs (ß = 1.11, 95% CI: 0.43, 1.79) in females. The largest reference values for Tvol based on BSA were 20.18 (17.79, 24.32) mL in males and 15.31 (14.05, 16.70) mL in females. CONCLUSIONS: Quantile regression analyses showed that a high BSA index, a decreased TSH level, and the prevalence of TNs were essential factors associated with the enlargement of the thyroid gland. Our findings reported the new reference values for Tvol determined by ultrasound based on gender and BSA in Chinese adults.

Evaluation of variation of saliva iodine and recommendations for sample size and sampling time: Implications for assessing iodine nutritional status.

BACKGROUND: Saliva iodine concentration (SIC) has been found to be a good indicator of iodine nutritional status. However, limited information is available regarding saliva iodine characteristics. AIMS: The study aimed to evaluate intra-day, intra-individual, and population SIC variation in order to provide information on optimal sample size and sampling time for assessing iodine nutritional status. METHODS: Twenty-nine healthy school-aged students were recruited. Iodine intake from diet and water, and iodine excretion through urine and feces were assessed over a three-day period. Saliva samples were collected six times a day. RESULTS: Diurnal variations were observed in SIC corresponding to iodine intake. The mean CV in SIC was lower than that for 24-hour urinary iodine concentration (24-h UIC) and 24-hour urinary iodine excretion (24-h UIE) not only at the individual level (42.73% vs. 47.71% and 49.69%) but also at the population level (71.29% vs. 100.43% and 72.49%). The number of saliva samples needed to estimate the iodine level with 95% CI within precision ranges of ±10%, ±20% was 55, 14 in an individual, and 180, 45 in a population. There was a good correlation between post-lunch SIC and total daily iodine intake. CONCLUSIONS: Saliva iodine has utility for evaluating the recent iodine nutrition of individuals and populations. The variation in SIC was lower than that for 24-h UIC and 24-h UIE. Saliva may be preferred over urine because of its ease of collection. Fourteen samples are needed to assess individual iodine status and forty-five saliva samples for assessment of population iodine status with reasonable precision. We recommend that saliva samples be collected after 14:00 in a day.