Induced emotion counter-regulation affects attentional inhibition of emotional information: ERP evidence from a randomized manipulation approach.

Automatic emotion counter-regulation refers to an unintentional attentional shift away from the current emotional state and toward information of the opposite valence. It is a useful emotion regulation skill that prevents the escalation of current emotional state. However, the cognitive mechanisms of emotion counter-regulation are not fully understood. Using a randomization approach, this study investigated how automatic emotion counter-regulation impacted attentional inhibition of emotional stimuli, an important aspect of emotion processing closely associated with emotion regulation and mental health. Forty-six university students were randomly assigned to an emotion counter-regulation group and a control group. The former group watched an anger-inducing video to evoke automatic emotion counter-regulation of anger, while the latter group watched an emotionally neutral video. Next, both groups completed a negative priming task of facial expressions with EEG recorded. In the emotion counter-regulation group, we observed an enhanced attentional inhibition of the angry, but not happy, faces, as indicated by a prolonger response time, a larger N2, and a smaller P3 in response to angry versus happy stimuli. These patterns were not observed in the control group, supporting the role of elicited emotion counter-regulation of anger in causing these modulation patterns in responses.

Chronic Excess Iodine Intake Inhibits Bone Reconstruction Leading to Osteoporosis in Rats.

BACKGROUND: Although iodine modulates bone metabolism in the treatment of thyroid disease, the effect of iodine intake on bone metabolism remains less known. OBJECTIVE: This study evaluated the effect of excess iodine intake in rats on bone reconstruction in the 6th and 12th month of intervention. METHOD: Rats were treated with different doses of iodinated water: the normal group (NI, 6.15 µg/d), 5-fold high iodine group (5HI, 30.75 µg/d), 10-fold high iodine group (10HI, 61.5 µg/d), 50-fold high iodine group (50HI, 307.5 µg/d), and 100-fold high iodine group (100HI, 615 µg/d). Thyroid hormone concentrations were determined by a chemiluminescent immunoassay. Morphometry and microstructure of bone trabecula were observed by hematoxylin and eosin staining and microcomputed tomography, respectively. Alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) staining were performed to evaluate the activity of osteoblasts and osteoclasts, respectively. RESULTS: The 24-h urine iodine concentration increased with iodine intake. The rats in the HI groups had higher serum thyroid-stimulating hormone and decreased serum free thyroxine concentrations in the 12th month than the NI group (all P < 0.05). The percentage of the trabecular bone area and osteoblast perimeter in the 100HI group were significantly lower than those in the NI group (P < 0.05). Increased structure model index was observed in the 50HI and 100HI groups compared with the NI group in the 6th month and increased trabecular separation in the 12th month (all P < 0.05). ALP and TRAP staining revealed osteoblastic bone formation was reduced, and the number of TRAP+ multinucleated cells decreased with increasing iodine intake. CONCLUSIONS: Excess iodine intake may increase the risk of hypothyroidism in rats. Chronic excess iodine intake can lead to abnormal changes in skeletal structure, resulting in reduced activity of osteoblasts and osteoclasts, which inhibits the process of bone reconstruction and may lead to osteoporosis.

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.

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.

Mechanism of multi-organ compensation under different iodine intake in pregnant rats: results from a repeated-measures study of iodine metabolism.

PURPOSE: This study aimed to explore the differences in iodine metabolism and expression of NIS and Pendrin in pregnant rats under different iodine nutritional status. METHODS: Female Wistar rats were divided into four groups: low iodine (LI), normal iodine (NI), ten fold high iodine (10HI), and fifty fold high iodine (50HI). The intervention began after one week of adaptive feeding. Iodine metabolism experiments were performed beginning on the 15th day of pregnancy. 24-h iodine intake and excretion were calculated. The concentrations of iodine in urine, fecal, thyroid, and placenta were measured by ICP-MS. PCR and Western Blot were used to detect the mRNA levels and cell membrane protein of sodium/iodide symporter (NIS) and Pendrin in the small intestine, thyroid, kidney, and placenta. RESULTS: Fecal iodine excretion (FIE) and urinary iodine excretion (UIE) in the 50HI group were significantly higher than those in the NI group (P < 0.05). The NIS protein and mRNA in the kidney and small intestine have an upward trend in iodine deficiency and a downward trend in iodine excess. Thyroid and placental iodine storage in the 50HI group were significantly higher than those in the NI group (P < 0.05). NIS, Pendrin protein, and mRNA in the thyroid and placenta tend to increase when iodine is deficient and decrease when there is excess. CONCLUSION: Iodine excretion and iodine stores in the placenta and thyroid gland are positively correlated with iodine intake. NIS and Pendrin are also regulated by iodine intake.

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).

Clinical Experience With Acute Phase Repair of Facial Nerve Dissections.

The purpose of this study was to evaluate the facial nerve recovery of patients with traumatic facial nerve transections after tension-free end-to-end nerve epineural anastomosis during the acute phase. A total of 11 patients with traumatic facial nerve transections during the acute phase were surgically treated in the authors' department from November 2016 to August 2022. The case data and imaging data were collected from the patients, and the House-Brackman evaluation system of the facial nerve was applied to assess the recovery of facial nerve function, and the higher the grade, the worse the facial nerve function. Of the patients, 90.9% recovered to H-B grade II or below, and there were differences in the degree of recovery of the facial nerve function among the branches, and the ones that recovered to H-B grade II or below after surgery were 100% of the zygomatic branch, of which 80% were H-B grade I, 100% of the buccal branch, of which 44.4% were H-B grade I, 88.9% of the marginal mandibular branch, and 66.7% of the temporal branch. The study showed that the recovery rate of young patients was better than that of middle-aged and old people, and the best recovery of each branch of the facial nerve was the zygomatic branch, followed by the buccal branch, the marginal mandibular branch, and the worse was the temporal branch.

Effect of Tissue Pedicle Position on Postoperative Recovery From Severe Auricular Laceration.

BACKGROUND: Postoperative recovery from severe auricular lacerations varies significantly. However, few studies have sought to clarify the risk factors associated with the prognosis of severe auricular lacerations, and little attention has been paid to the intraoperative management of severe auricular lacerations and early postoperative intervention. The purpose of this study was to analyze the risk factors that may affect the prognosis of severe auricular lacerations. METHODS: Case data and imaging data of patients with severe auricular lacerations treated in our department between January 2018 and September 2022 were collected. A total of 90 patients (90 severe auricular lacerations) were included in the analysis and were divided into good group (68 cases) and poor group (22 cases) according to postoperative recovery, which was defined as poor postoperative recovery when postoperative auricular blood supply disorders required interventional treatment or second stage plastic surgery. RESULTS: The percentage of ventral tissue pedicles in the poor recovery group was 77.3% ( P <0.001). The proportion of ventral tissue pedicle was significantly higher in the poor postoperative group than in the good postoperative group, and ventral tissue pedicle [odds ratio (OR)=12.22, P =0.002] was an independent risk factor for poor postoperative recovery from severe auricular laceration. CONCLUSIONS: The prognosis of patients with severe auricular lacerations differs between the different tissue pedicle locations, and prophylactic treatment of patients with ventral tissue pedicles is beneficial. In addition, patients with ventral tissue pedicles should be informed in advance of their increased risk of surgical failure.

Two new iridoid glycosides from the whole plant of Rehmania piasezkii.

Two new iridoid glycosides, piasezkiiosides A (1) and B (2), were isolated from aqueous extract of the whole plant of Rehmannia piasezkii. Their structures were established from the spectroscopic data, chemical transformation, and X-ray diffraction analysis. Compound 1 exhibited weak hepatoprotective activity against APAP-induced HepG2 cell damage.

Four new iridoid glycosides from the roots of Rehmannia glutinosa.

Four new iridoid glycosides (1-4), rehmaglutosides L-O, were isolated from the air-dried roots of Rehmannia glutinosa. Their structures were established from the spectroscopic data obtained and by chemical evidence. The known mellittoside (5) and ajugol (6) were also obtained in the current investigation, and the structure of mellittoside was unequivocally defined using X-ray diffraction data. Compounds 1-6 were tested for their cytotoxicity against five human tumor cell lines and proliferation effects on Lactobacillus Reuteri.

Seven new pentasaccharides from the roots of Rehmannia glutinosa.

Seven new pentasaccharides (1-7), rehmaglupentasaccharides A-G, were isolated from the air-dried roots of Rehmannia glutinosa. Their structures were established from the spectroscopic data obtained and by chemical evidence. The known verbascose (8) and stachyose (9) were also obtained in the current investigation, and the structure of stachyose was unequivocally defined using X-ray diffraction data. Compounds 1-9 were tested for their cytotoxicity against five human tumor cell lines, influence on dopamine receptor activation, and proliferation effects against Lactobacillus reuteri.

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.

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.

Adsorption Recycling and High-Value Reutilization of Heavy-Metal Ions from Wastewater: As a High-Performance Anode Lithium Battery.

The dazzling adsorbent products make people overlook the harm of heavy metals adsorbed on them. Hazardous waste adsorbents cause secondary pollution. In this study, waste lignocellulose was dissolved by alkaline urea solvent and high-intensity ultrasound, then cross-linked by epichlorohydrin to make hydrogel, which was utilized to adsorb toxic heavy-metal wastewater. In situ deposition and high-temperature carbonization turn the gel that has absorbed heavy metals into carbon aerogel-loaded metal oxide energy storage materials that may be employed as anodes in lithium-ion batteries with excellent electrochemical performance. The best reversible capacity was 435.86 mAh g-1 after 100 cycles at 0.2C, indicating that the hazardous solid waste generated by the removal of heavy metals using biomass-based adsorbent has potential lithium battery applications. Thus, we provide a fresh perspective on the efficient recycling of heavy metals as well as an environmentally friendly, high-value conservation strategy for lowering the danger of heavy-metal hazardous wastes.

Transcriptome analyses shed light on floral organ morphogenesis and bract color formation in Bougainvillea.

BACKGROUND: Bougainvillea is a popular ornamental plant with brilliant color and long flowering periods. It is widely distributed in the tropics and subtropics. The primary ornamental part of the plant is its colorful and unusual bracts, rich in the stable pigment betalain. The developmental mechanism of the bracts is not clear, and the pathway of betalain biosynthesis is well characterized in Bougainvillea. RESULTS: At the whole-genome level, we found 23,469 protein-coding genes by assembling the RNA-Seq and Iso-Seq data of floral and leaf tissues. Genome evolution analysis revealed that Bougainvillea is related to spinach; the two diverged approximately 52.7 million years ago (MYA). Transcriptome analysis of floral organs revealed that flower development of Bougainvillea was regulated by the ABCE flower development genes; A-class, B-class, and E-class genes exhibited high expression levels in bracts. Eight key genes of the betalain biosynthetic pathway were identified by homologous alignment, all of which were upregulated concurrently with bract development and betalain accumulation during the bract initiation stage of development. We found 47 genes specifically expressed in stamens, including seven highly expressed genes belonging to the pentose and glucuronate interconversion pathways. BgSEP2b, BgSWEET11, and BgRD22 are hub genes and interacted with many transcription factors and genes in the carpel co-expression network. CONCLUSIONS: We assembled protein-coding genes of Bougainvilea, identified the floral development genes, and constructed the gene co-expression network of petal, stamens, and carpel. Our results provide fundamental information about the mechanism of flower development and pigment accumulation in Bougainvillea, and will facilitate breeding of cultivars with high ornamental value.

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.

Four ionones and ionone glycosides from the whole plant of Rehmannia piasezkii.

Four new ionones and ionone glycosides (1-4) were isolated from the whole plant of Rehmannia piasezkii Maxim. Their planar structures as well as absolute configuration were confirmed via spectroscopic analysis, ECD calculation, and X-ray crystallography. Compounds 1-4 were tested for their cytotoxicity against five human tumor cell lines and ability to inhibit LPS-activated NO production in the BV2 cell line.

[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.

Intra-individual and inter-individual variations in iodine intake and excretion in adult women: implications for sampling.

Iodine intake and excretion vary widely; however, these variations remain a large source of geometric uncertainty. The present study aims to analyse variations in iodine intake and excretion and provide implications for sampling in studies of individuals or populations. Twenty-four healthy women volunteers were recruited for a 12-d sampling period during the 4-week experiment. The duplicate-portion technique was used to measure iodine intake, while 24-h urine was collected to estimate iodine excretion. The mean intra-individual variations in iodine intake, 24-h UIE (24-h urinary iodine excretion) and 24-h UIC (24-h urinary iodine concentration) were 63, 48 and 55 %, respectively, while the inter-individual variations for these parameters were 14, 24 and 32 %, respectively. For 95 % confidence, approximately 500 diet samples or 24-h urine samples should be taken from an individual to estimate their iodine intake or iodine status at a precision range of ±5%. Obtaining a precision range of ±5% in a population would require twenty-five diet samples or 150 24-h urine samples. The intra-individual variations in iodine intake and excretion were higher than the inter-individual variations, which indicates the need for more samples in a study on individual participants.

Trimester-Specific Thyroid Function in Pregnant Women with Different Iodine Statuses.

OBJECTIVES: To explore trimester-specific thyroid function changes under different iodine statuses throughout pregnancy. METHODS: A cross-sectional study was conducted to assess the pregnancy iodine status, and 2,378 healthy pregnant women covering all 3 trimesters were recruited. Urinary iodine concentration (UIC) was measured by collecting spot urine samples. Blood samples were collected to evaluate thyroid function. Thyroid B-ultrasonography was conducted to measure the thyroid volume (Tvol). RESULTS: The median UIC was 168 µg/L (111-263 µg/L). The UIC, free triiodothyronine (FT3), and free thyroxine (FT4) were significantly decreased as the pregnancy progressed (p < 0.001, p for trend <0.001), while Tvol increased (p < 0.001, p for trend <0.001). Thyrotropin (TSH) was significantly different between the 3 trimesters and showed an upward trend (p < 0.001), but the p for trend was not significant (p for trend = 0.88). After stratification by UIC, there were no significant differences in serum TSH, FT4, or FT3 level between UIC groups. Tvol was significantly higher in the UIC ≥500 µg/L group in the first trimester (ß: 2.41, 95% CI: 1.09-3.72, p <0.001), as well as in the 250 ≤ UIC < 500 µg/L group (ß: 1.65, 95% CI: 0.61-2.70, p < 0.001) and UIC ≥500 µg/L group (ß: 3.35, 95% CI: 1.96-4.74, p < 0.001) in the third trimester. CONCLUSIONS: No difference was observed in TSH, FT3, or FT4 among the different iodine status groups throughout pregnancy. Tvol increased as the pregnancy progressed, and it was especially higher in the UIC ≥500 µg/L group in the first and third trimesters.