Summary Objective This study aims to evaluate the association of serum iodine concentration (SIC) with urinary iodine concentration (UIC) and thyroid function in pregnant women, as well as to provide the reference range of SIC of pregnant women in iodine‐sufficiency area. Methods Pregnant women were enrolled in the Department of Obstetrics, Tanggu Maternity Hospital, Tianjin from March 2016 to May 2017. Fasting venous blood and spot urine samples were collected. Serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid‐stimulating hormone (TSH), thyroglobulin (Tg), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), UIC and SIC were measured. Results One thousand and ninety‐nine participants were included in this study. The median UIC was 156 μg/L. The median SIC was 108 μg/L, and the 95% reference interval for SIC was 65.6‐164.7 μg/L. SIC was positively correlated with UIC ( r = 0.12, P < 0.001), FT3 ( r = 0.23, P < 0.001), and FT4 ( r = 0.50, P < 0.001) and was inversely correlated with TSH ( r = −0.14, P < 0.001). Pregnant women with a SIC < 79.9 μg/L had a higher risk of hypothyroxinemia compared to those with higher SIC (OR = 2.44, 95% CI: 1.31‐4.75). Those having SIC > 138.5 μg/L were more likely to have thyrotoxicosis than those with lower SIC values (OR = 13.52, 95% CI: 4.21‐43.36). Conclusions Serum iodine level is associated with UIC and thyroid function in pregnant women. Low SIC was associated with increased risk for iodine deficiency and hypothyroxinemia, while high SIC was related to excess and thyrotoxicosis.
Introduction: The effect of T lymphocytes on atrial fibrillation (AF) is still unclear. We aimed to assess the associations between the T-lymphocyte subgroup distribution and incident AF and AF prognosis. Methods: Consecutive patients were enrolled from June 2020 to October 2021. Their T-cell subgroups, including CD3, CD4, and CD8 T cells, and the CD4/CD8 ratio (CDR) were measured. We assessed the relationships between the CDR and composite endpoints, including hospitalization due to heart failure, stroke or systemic embolism, and cardiovascular mortality rates. Results: A total of 45,905 patients, among whom 818 had AF, were enrolled. The proportions of the T-lymphocyte subgroups CD3 (OR: 0.9995; 95% CI: 0.9993–0.9997, p < 0.001), CD4 (OR: 0.9995; 95% CI: 0.9991–0.9998, p = 0.004), and CD8 (OR: 0.9988; 95% CI: 0.9984–0.9992, p < 0.001) and the CDR (OR: 1.2714; 95% CI: 1.1355–1.4165, p < 0.001) were correlated with AF incidence. The CDR was associated with AF incidence (OR: 1.1998; 95% CI: 1.0746–1.3336, p < 0.001) after adjustment. High CDR was associated with a higher rate of hospitalization due to heart failure (HR: 3.45; 95% CI: 1.71–6.96, p < 0.001), stroke, or systemic embolism (HR: 2.54; 95% CI: 1.32–4.91, p = 0.005), and cardiovascular mortality (HR: 2.25; 95% CI: 1.05–4.84, p = 0.038). There was no significant difference in all-cause mortality between CDR strata (HR: 1.61; 95% CI: 0.90–2.87, p = 0.111). Conclusion: Elevated CDR was positively associated with the incidence and prognosis of AF. This finding may help improve the prevention and treatment of AF.
Variations in different urinary measurements for evaluating iodine status are concerning to clinicians and researchers. The present study aimed to analyze the interindividual and intraindividual variations in the urinary iodine concentration (UIC) and urinary iodine/creatinine (UI/Cr) ratio and evaluate their application in assessing the iodine nutrition of preschool children. Four repeated spot urine samples were collected from 163 children at different times within one day. The urinary iodine concentration (UIC) and urinary creatinine concentration (UCr) were measured, and the UI/Cr ratio was calculated. The UIC ( < 0.001) and urinary iodine/creatinine ratio ( = 0.019) of multiple measurements were significantly different. The UIC of morning urine was highest (99.83 μg/L) and then gradually decreased with collection time ( < 0.001). In contrast, the UI/Cr ratio of morning urine samples increased with collection time. By computing the mean intraindividual and interindividual coefficients of variance (CV), the intraindividual variation of the UI/Cr ratio (68%) was significantly lower than that of the UIC (86%). Nevertheless, the interindividual variation was lowest in the UIC (78.62%) of morning urine. In addition, the UIC and UI/Cr ratio showed moderate correlations (r = 0.52, < 0.001), with kappa values of 0.42 in assessing iodine nutrition. The UIC of morning urine samples taken at 8:00–10:00 am was perhaps more stable and reliable in evaluating the iodine nutrition of preschool children at the population level. The UI/Cr ratio showed lower intraindividual variation and may be more suitable for assessing individual iodine nutrition.
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.
Abstract Context The effectiveness of saliva iodine concentration (SIC) in evaluating iodine status in children is not clear. Objective We aimed to explore associations between SIC and assessed indicators of iodine status and thyroid function. Design Cross-sectional study. Setting Primary schools in Shandong, China. Participants Local children aged 8 to 13 years with no known thyroid disease were recruited to this study. Main outcome measures Blood, saliva, and urine samples were collected to evaluate thyroid function and iodine status. Results SIC positively correlated with spot urinary iodine concentration (r = 0.29, P < 0.0001), 24-hour urinary iodine concentration (r = 0.35, P < 0.0001), and 24-hour urinary iodine excretion (r = 0.40, P < 0.0001). The prevalence of thyroid nodules (TN) and goiter showed an upward trend with SIC quantiles (P for trend < 0.05). Children with SIC <105 μg/L had a higher risk of insufficient iodine status (OR = 4.18; 95% CI, 2.67-6.56) compared with those with higher SIC. Those having SIC >273 μg/L were associated with greater risks of TN (OR = 2.70; 95% CI, 1.38-5.26) and excessive iodine status (OR = 18.56; 95% CI, 5.66-60.91) than those with lower SIC values. Conclusions There is a good correlation between SIC and urinary iodine concentrations. It is of significant reference value for the diagnosis of iodine deficiency with SIC of less than 105 μg/L and for the diagnosis of iodine excess and TN with SIC of more than 273 μg/L. Given the sanitary nature and convenience of saliva iodine collection, SIC is highly recommended as a good biomarker of recent iodine status in school-aged children.
Abstract 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.
Abstract Background The relationship between low serum iodine and thyroid dysfunctions in adults is not well understood. This study aimed to explore the relationship between serum and urinary iodine and thyroid dysfunctions in the adult population. Methods : A total of 1320 participants were included in the final analysis. We collected basic demographic information, as well as blood and spot urine samples, to determine serological indices and iodine nutritional status of subjects. Results : The median (IQR) serum iodine (SI) level was 70.5µg/L (59.6–83.6µg/L). Compared to those with 59.6µg/L ≤ SI < 83.6µg/L, subjects with SI ≤ 59.6µg/L had a higher risk of thyroid dysfunctions (OR = 1.72, 95%CI: 1.08–2.75), clinical hypothyroidism (OR = 16.4, 95%CI: 3.72–72.2) and sUIC < 100µg/L (OR = 1.41, 95%CI: 1.05–2.00). The areas under the ROC curve of SI (0.554, P = 0.02) was significantly higher than that of sUIC/UCr (0.446, P = 0.005). Conclusions : Serum iodine is more sensitive than urine iodine in the diagnosis of thyroid dysfunctions. Low serum iodine concentration is associated with an increased risk of thyroid dysfunctions, especially hypothyroidism.
Background: The relationship between low serum iodine and thyroid dysfunctions in adults is not well understood. This study aimed to explore the relationship between serum and urinary iodine and thyroid dysfunctions in the adult population.Methods: A total of 1320 participants were included in the final analysis. We collected basic demographic information, as well as blood and spot urine samples, to determine serological indices and iodine nutritional status of subjects.Results: The median (IQR) serum iodine (SI) 1 level was 70.5μg/L (59.6-83.6μg/L). Compared to those with 59.6μg/L ≤ SI < 83.6μg/L, subjects with SI ≤ 59.6μg/L had a higher risk of thyroid dysfunctions (OR = 1.72, 95%CI: 1.08 – 2.75), clinical hypothyroidism (OR = 16.4, 95%CI: 3.72 – 72.2) and sUIC < 100μg/L (OR = 1.41, 95%CI: 1.05 - 2.00). The areas under the ROC curve of SI (0.554, P =0.02) was significantly higher than that of sUIC/UCr (0.446, P =0.005).Conclusions: Serum iodine is more sensitive than urine iodine in the diagnosis of thyroid dysfunctions. Low serum iodine concentration is associated with an increased risk of thyroid dysfunction, especially hypothyroidism.
<b><i>Objectives:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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) (β = 7.22, 95% CI: 5.33, 9.12), thyroid-stimulating hormone (TSH) (β = −1.48, 95% CI: −2.39, −0.57), thyroid nodules (TNs) (β = 6.70, 95% CI: 2.19, 11.22), and metabolic syndrome (MetS) (β = 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 (β = 9.64, 95% CI: 2.66, 16.61), TSH (β = −0.78, 95% CI: −1.16, −0.39), and TNs (β = 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. <b><i>Conclusions:</i></b> 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.
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