Retrospective Cross-Sectional Study of the Relationship of Thyroid Volume and Function with Anthropometric Measurements, Body Composition Analysis Parameters, and the Diagnosis of Metabolic Syndrome in Euthyroid People Aged 18-65.

Background and Objectives: The thyroid is a key endocrine gland for the regulation of metabolic processes. A body composition analysis (BCA) is a valuable complement to the assessment of body mass index, which is derived only from body weight and height. This cross-sectional retrospective study aimed to investigate the relationships between thyroid volume (TV) and thyroid function parameters, anthropometric measurements, BCA parameters, and the presence of metabolic syndrome (MetS) in adults without clinically overt thyroid disease. Material and Methods: This study involved 45 people (females: 57.8%; MetS: 28.9%) hospitalized for planned diagnostics without signs of acute illness or a deterioration of their health and without thyroid disease, who underwent thyroid ultrasound scans, biochemical tests to assess their thyroid function, MetS assessments, anthropometric measurements, and BCAs using the bioelectrical impedance method. Results: The TV was significantly larger in people with MetS compared to people without MetS. The TV was significantly higher and the serum thyrotropin (TSH) concentration was significantly lower in overweight and obese people than in normal and underweight people. The free triiodothyronine (FT3) serum concentration and TV were correlated with waist circumference and some parameters of the BCA, and the FT3 concentration was also correlated with the body mass index, waist-hip ratio, and waist-height ratio. No significant correlations were found between the FT4 and TSH and the results of the anthropometric and BCA measurements. Conclusions: Even in a population of euthyroid patients without clinically overt thyroid disease, there were some significant relationships between the volume and function of the thyroid gland and the results of their anthropometric parameters, BCAs, and the presence of MetS features.

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

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

Study on influential factors and reference values for thyroid volume in Chinese children aged 6-12 years.

The purpose of the current study was to research the factors influencing thyroid volume (TVOL) in 6-12-year-old children and update the reference values. A cross-sectional study was carried out in iodine-sufficient areas of four provinces in China. Urine, edible salt and drinking water samples were collected from children. Children's height, weight and TVOL were measured. Ridge regression was used to screen variables for solving the multicollinearity problem. Quantile regression was used to analyse the relationship between the quantiles of TVOL and other variables. In total, 5653 children aged 6-12 years were enrolled in this study, including 2838 boys and 2815 girls. There was no significant difference in TVOL between boys and girls (P > 0·05). Spearman correlation analysis showed that total TVOL was positively correlated with age, height, weight, body surface area (BSA) and BMI, and the correlation coefficients were 0·616, 0·663, 0·669, 0·685 and 0·479, respectively. Among them, the correlation between TVOL and BSA was the strongest. According to the ridge regression results, age and BSA influenced TVOL, and the ridge regression coefficients were 0·13 and 0·94, respectively. Quantile regression further showed that age and BSA had significant influences on the whole TVOL distribution (P < 0·001). Therefore, the TVOL of children aged 6-12 years in China was mainly influenced by age and BSA, and reference values for TVOL of different genders based on age and BSA were established.

Comparative Analysis of Five Correction Methods for Thyroid Volume by Ultrasound and Their Recommended Reference Values in Chinese Children Aged 8-10 Years.

Considering the influence of body's growth and development on thyroid volume (TVOL), whether five existed corrected methods could be applied to correct TVOL remains unclear, in terms of Chinese children's increased growth and development trends. This study aimed to compare the applicability of five correction methods for TVOL: Body Surface Area corrected Volume (BSAV), Body Mass Indicator corrected Volume (BMIV), Weight and Height corrected Volume Indicator (WHVI), Height corrected Volume Indicator 1 (HVI1) and Height corrected Volume Indicator 2 (HVI2); to establish the reference values for correction methods. The data of Iodine Nutrition and Thyroid Function Survey was used to analyse the differences in TVOL between normal and abnormal thyroid function children. Data of National Iodine Deficiency Disorders Survey were used to compare five correction methods and to establish their reference values. The median urinary iodine concentration of children surveyed were 256.1µg/L in 2009 and 192.6µg/L in 2019, respectively. No significant difference was found in TVOL and thyroid goitre rate between children with normal and abnormal thyroid function. In the determination of goitre, HVI1, HVI2, BSAV and BMIV all showed high agreement with TVOL, while the area under the ROC curve (AUC) of WHVI was relatively low for children aged 8(AUC=0.8993) and 9(AUC=0.8866). Most differences of TVOL between light and heavy weight, short and tall height children can be eliminated by BSAV correction. BSAV was the best method of TVOL correction in this research. Reference values were established for corrected thyroid volumes in Chinese children aged 8-10 years by sex.

Study on association between height, weight, iodine supplementation and thyroid volume.

The policy of Universal Salt Iodisation (USI) could reduce population's thyroid volume (TVOL) in iodine deficiency areas. Conversely, the improved growth and developmental status of children might increase the TVOL accordingly. Whether the decreased TVOL by USI conceals the increase effect of height and weight on TVOL is unclear. The aim of this study was to analyse the association between height, weight, iodine supplementation and TVOL. Five national Iodine Deficiency Disorder surveys were matched into four pairs according to the purpose of analysis. County-level data of both detected by paired surveys were incorporated; 1:1 random pairing method was used to match counties or individuals. The difference of TVOL between different height, weight, different iodine supplementation measures groups and the association between TVOL and them were studied. The mean height and weight of children aged 8-10 years increased from 129·9 cm and 26·9 kg in 2002 to 136·2 cm and 32·1 kg in 2019, while the median TVOL decreased from 3·10 ml to 2·61 ml. Iodine supplementation measures can affect TVOL; after excluding iodine effects, the median TVOL was increased with the height and weight. On the other side, after excluding the influence of height and weight, the median TVOL remained decreased. Only age, weight and salt iodine were significantly associated with TVOL in multiple linear models. Development of height and weight in children is the evidence of improved nutrition. The decreased TVOL caused by iodised salt measures conceals the increase effect of height and weight on TVOL. Age, weight and salt iodine affect TVOL significantly.

Association between exposure to radioactive iodine after the Chernobyl accident and thyroid volume in Belarus 10-15 years later.

BACKGROUND: While there is a robust literature on environmental exposure to iodine-131 (131I) in childhood and adolescence and the risk of thyroid cancer and benign nodules, little is known about its effects on thyroid volume. METHODS: To assess the effect of 131I dose to the thyroid on the volume of the thyroid gland, we examined the data from the baseline screening of the Belarusian-American Cohort Study of residents of Belarus who were exposed to the Chernobyl fallout at ages ≤18 years. Thyroid dose estimates were based on individual thyroid activity measurements made shortly after the accident and dosimetric data from questionnaires obtained 10-15 years later at baseline screening. During baseline screening, thyroid gland volume was assessed from thyroid ultrasound measurements. The association between radiation dose and thyroid volume was modeled using linear regression where radiation dose was expressed with power terms to address non-linearity. The model was adjusted for attained age, sex, and place of residence, and their modifying effects were examined. RESULTS: The analysis was based on 10,703 subjects. We found a statistically significant positive association between radiation dose and thyroid volume (P < 0.001). Heterogeneity of association was observed by attained age (P < 0.001) with statistically significant association remaining only in the subgroup of ≥18 years at screening (P < 0.001). For this group, increase in dose from 0.0005 to 0.15 Gy was associated with a 1.27 ml (95% CI: 0.46, 2.07) increase in thyroid volume. The estimated effect did not change with increasing doses above 0.15 Gy. CONCLUSIONS: This is the first study to examine the association between 131I dose to the thyroid gland and thyroid volume in a population of individuals exposed during childhood and systematically screened 10-15 years later. It provides evidence for a moderate statistically significant increase in thyroid volume among those who were ≥ 18 years at screening. Given that this effect was observed at very low doses and was restricted to a narrow dose range, further studies are necessary to better understand the effect.

Metabolic syndrome and its components are associated with thyroid volume in adolescents.

OBJECTIVE: To explore the association between metabolic syndrome (MetS) and its component and thyroid volume in Chinese adolescents, and to compare the detection rate of MetS under the three different diagnostic criteria. METHODS: A total of 1097 school students (610 males and 487 females, ages 12-15 years) were enrolled. All the participants underwent physical examination, biochemical test, and thyroid gland ultrasonography. The thyroid volume of normal, overweight and obese group was compared. We also analyzed the association between the number of MetS components and thyroid volume. Linear and multiple linear regression were applied to explore the association between metabolic parameters and thyroid volume. RESULTS: The thyroid volume of the males in overweight (t = 3.784, P < 0.001) and obese group (t = 5.068, P < 0.001) was significantly larger than that in normal group; the thyroid volume of the females in overweight group (t = 4.627,P < 0.001) was significantly larger than that of normal group. As the number of MetS components increased, the thyroid volume also increased significantly (F = 10.64, P < 0.01). Height, weight, body mass index (BMI), waist circumference, hip circumference, systolic blood pressure, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), uric acid and triglyceride were all positively associated with thyroid volume in the adolescents (P all < 0.001). Meanwhile, there was a negative association between high-density lipoprotein cholesterol (HDL-C) and thyroid volume (P < 0.001). According to multiple linear regression, waist circumference (ß = 0.029, 95 %CI: 0.015 ~ 0.042; P < 0.01) and waist height ratio (ß = 3.317, 95 %CI: 1.661 ~ 4.973; P < 0.01) were predict factors of thyroid volume. No statistical difference was found in the detection rates of metabolic syndrome under the three diagnostic criteria. CONCLUSIONS: Overweight, obesity and metabolic syndrome was associated with adolescent thyroid volume. Central obesity may be an independent risk factor for thyroid enlargement in adolescents.

Long-term Observation of Thyroid Volume Changes in Hashimoto's Thyroiditis in a Series of Women on or off Levo-Thyroxine Treatment in an Area of Moderate Iodine Sufficiency.

CONTEXT: Large variations in thyroid volume (TV) have been reported in Hashimoto's thyroiditis (HT). The need for long-term levo-thyroxine (L-T4) administration in order to control TV, as well as to normalise thyroid function, has not been well defined. SUBJECTS AND METHODS: Retrospective data on TV in 94 adult women with HT were analysed in an ambulatory setting in Liguria, an area of moderate iodine sufficiency. TV was evaluated by means of ultrasonography (US). Thyroid function, anthropometric data, smoking habits and pharmaceutical drugs were registered at each examination. RESULTS: At the baseline, an atrophic gland was noted in 16% of the women, and goitre in 13%. The women were evaluated 56 and 102 months after the baseline examination. At the time of each examination, 50%, 78% and 83% of women, respectively, were on L-T4 treatment. Baseline TV was not significantly different in women on/off L-T4 treatment. However, in those on L-T4, TV decreased significantly over the period of follow-up, while in those without L-T4 treatment, it did not change. By the end of the study, the percentage of L-T4-treated women with an atrophic gland had increased to 27%, and that of women with goitre had dropped to 6%; in untreated women, only minor changes were noted. There was a significant negative correlation between TV% change and baseline TSH levels in HT women on L-T4 treatment. CONCLUSION: The majority of HT women living in an area of moderate iodine sufficiency have normal TV. Moreover, long-term L-T4 treatment can be used to control TV, as well as to maintain normal thyroid parameters.

The course of Autoimmune Thyroiditis in WOMEN.

Context: Although, many studies have been made on the clinical course of autoimmune thyroiditis, this study focused on women and the factors effecting the natural course such as Selenium. Objective: The study aimed to determine Hashimoto's thyroiditis (HT) clinical course in adults and the factors that could affect it. Design: The study was in a retrospective manner between 2010-2018. Subjects and Methods: 101 patients with HT were followed for 60.7±32.7 months. Biochemical and ultrasonographic data were collected. We investigated whether the age at diagnosis, family history, smoking habits, levothyroxine replacement therapy, and serum selenium (Se) levels influenced the disease course. Results: No relationship was observed between age and thyroid functions, thyroid volumes (TV), and autoantibody (Ab) levels at diagnosis. Ab levels were irrelevant with TV, echogenicity, and nodularity at diagnosis. However, initial TSH levels were significantly associated with anti-TPO levels (p=0.028, r=0.218). In the untreated group, thyroid functions seemed to be stable. TV decreased significantly in both treated and untreated patients (p<0.001). The decrease in TV was significantly higher in the treatment group (p=0.002). In euthyroid and subclinical hypothyroid patients, levothyroxine therapy did not affect the decrease in TV. Ab levels remained stable in untreated patients, but anti-TPO levels significantly decreased in treated patients (p<0.001). Smoking seemed to increase only anti-Tg levels (p=0.009). Family history was not associated with any of the studied parameters. Serum Se level was negatively correlated only with thyroid echostructure and only in treated patients. TV showed a "Gaussian distribution" in all patients at the diagnosis and at the end, independent of levothyroxine treatment. Conclusions: Most euthyroid patients remained euthyroid during five years of follow-up. The decrease in TV was significantly prominent with LT4 treatment. Importantly, TV followed a normal distribution instead of the bimodal distribution that is classically described.

Is there a Relationship between Serum IGF-1 and Thyroid Nodule, Thyroid or Ovarian Volume in Polycystic Ovarian Syndrome?

CONTEXT: Studies investigating the association between serum IGF-1, and thyroid nodule, ovarian or thyroid volume in polycystic ovarian syndrome (PCOS) are limited. OBJECTIVE: We aimed to analyze the association between serum IGF-1 level, and ovarian or thyroid volume, or thyroid nodule in PCOS. DESIGN: The study was performed between June 2017 and August 2019 as prospective design. SUBJECTS AND METHODS: Adult females with new-onset PCOS were included. The patients having comorbid illness, or using medication were excluded. Basic tests, thyroid and ovarian sonography were performed. The patients were grouped according to thyroid nodule(absent/present) and ovarian volume (<10mL/≥10mL). We planned to find a positive association between IGF-1, and thyroid nodule, thyroid or ovarian volume in PCOS. RESULTS: Of total 118 patients, 11(9%) had thyroid nodule. The patients with thyroid nodule had a higher ovarian volume (p=0.006). No correlation was found between GH or IGF-1, and thyroid or ovarian volume. IGF-1 was not a predictor for thyroid nodule or higher ovarian volume. Thyroid nodule was a significant predictor for higher ovarian volume. CONCLUSION: Our study is the first to analyze the association between IGF-1 and thyroid nodule in PCOS. We found that thyroid nodule was associated with thyroid and ovarian volume, but IGF-1 was not associated with thyroid nodule, thyroid or ovarian volume.

Schoolchildren thyroid volume in North Macedonia: data from a national survey in an iodine-sufficient country.

PURPOSE: North Macedonia is historically iodine deficient, but due to the longstanding and effective preventive measures, it has been considered iodine replete since 2003. The aim of the recent national survey was to re-evaluate iodine status and to measure thyroid volume (TVol) by ultrasound in schoolchildren as a representative of the general population. METHODS: A stratified probability proportionate to size cluster sampling was used to obtain a representative national sample of school children aged 7-10 years between the 28th of March and 4th of October 2016. Thyroid volume (TVol) was measured using ultrasonography in 1188 children. All TVol measurements were done by a single operator and their medians were compared with an international reference standard. RESULTS: Significant positive correlation was found between Tvol and age, height, weight, body surface area (BSA), body mass index (BMI) in both girls and boys (p < 0.001), but not between TVol and urinary ioidine concentration (UIC). The most important predictors for Tvol in all children were age, height, weight, BMI, and BSA ( all p < 0.001). In multivariate regression, independent predictors for TVol were only BSA (p < 0.001) and age (p = 0.004) after being adjusted for sex, BMI, and UIC (R2 = 0.291). The 97th percentile of Tvol in our survey was generally higher than in the reference study and goiter prevalence of 18.3% in boys and 15.6% in girls was found compared to the international standard. CONCLUSION: In our survey, Tvol of schoolchildren was larger than in the international reference study, although iodine nutritional status of the country has been considered sufficient for many years. In countries and regions with long and effective, well-documented iodine prophylaxis, the optimal way to have realistic normative TVol would be to create their TVol reference limits. Therefore, the provided data for TVol measured in our survey could be proposed as the national reference TVol for schoolchildren aged 7-10 years.

Assessment of thyroid functions and thyroid volume in normal pregnant Egyptian females.

The normal range of thyroid functions during pregnancy differs between ethnic groups. This study assessed the thyroid functions in normal pregnant Egyptian females. Thyroid peroxidase antibodies (TPO Abs) and thyroid volume were also assessed. The study included 150 normal pregnant Egyptian females, recruited from Cairo University Hospital Antenatal Care Clinic (50 in each trimester), with 40 age-matched non-pregnant females, as a control group. Serum thyroid stimulating hormone (TSH) and TPO Abs were measured. Thyroid volume was assessed by ultrasonography. TSH ranges were 0.21-1.7, 0.52-3.2 and 0.72-2.6 mIU/L during first, second and third trimesters, respectively. The mean TSH level in pregnant females was significantly lower than that of non-pregnant women (1.2 ± 0.7 vs 2.7 ± 0.9 mIU/L, p < .001). TPO Abs were significantly higher in the first trimester compared to both second and third trimesters (p < .001 for both). Thyroid volume of pregnant females was non-significantly higher than that of non-pregnant control subjects (p = .126). A significant positive correlation was found between thyroid volume and body mass index in pregnant females (p < 0.001). Our study established trimester-specific reference ranges for thyroid functions in normal pregnant Egyptian females. A larger population-based study would help to confirm those ranges. Thyroid volume was non-significantly higher than that of non-pregnant control subjects.

Thyroid volume and nodular and diffuse thyroid diseases by ultrasonography in pregnant women: A case-control study.

BACKGROUND: Currently, it is shown that pregnancy may have an impact on the thyroid that can be leading to pregnancy complications such as abortion, preeclampsia, and preterm delivery. The objective was to compare the thyroid volume, number and characteristics of thyroid nodules, and prevalence of diffuse thyroid diseases in a sample of Iranian pregnant women in the first trimester to nonpregnant women. MATERIALS AND METHODS: This case-control study was conducted on 298 pregnant and 290 nonpregnant women. Thyroid volume, maximum diameter of thyroid nodules and prevalence of moderate to highly suspicious thyroid nodules, Hashimoto's appearance and goiter were assessed using thyroid ultrasonography. Antithyroperoxidase (TPO) antibodies were measured if the sonographic features were highly suggested for Hashimoto's thyroiditis. RESULTS: The mean of total thyroid volume in pregnant and nonpregnant women was 6 and 6.5 ml, respectively (P = 0.053), and the median (interquartile range) was 6.2 and 5.5, respectively. Nodules were observed in 16.4% of pregnant and 16.6% of nonpregnant women (P = 0.845). Hashimoto's thyroiditis was detected in 6.7% of pregnant and 12.4% of nonpregnant women (P = 0.013). Anti-TPO antibodies were detected in 5% of pregnant and 9.3% of nonpregnant women (P = 0.034). CONCLUSION: The thyroid volume and nodule characteristics in the first trimester of pregnancy were similar to nonpregnant women. Hashimoto's thyroiditis and anti-TPO antibodies in pregnant women were significantly lower than in nonpregnant women.

EXENATIDE TREATMENT REDUCES THYROID GLAND VOLUME, BUT HAS NO EFFECT ON THE SIZE OF THYROID NODULES.

CONTEXT: Exenatide is a Glucagon-like Peptide-1 receptor agonist, which is widely used for type 2 diabetes mellitus (T2DM). Limited and conflicting results are present about the effect of exenatide on the thyroid gland. OBJECTIVE: The aim of this study was to evaluate the effect of exenatide treatment on structural and functional features of the thyroid gland in patients with T2DM. DESIGN: The study was a prospective study, performed between 2015 and 2017. The laboratory values and thyroid ultrasonography features were compared before and after exenatide treatment. SUBJECTS AND METHODS: The study included 39 obese diabetic patients. After inclusion to the study exenatide was started and patients were followed up for 6 months. Total thyroid volume, thyroid function tests, serum carcinoembryonic antigen (CEA) and calcitonin levels, the size and appearance of thyroid nodules were compared between baseline and after 6 months of treatment. RESULTS: Exenatide at a dose of 5µg bid was started, increased to 10 µg bid after 4 weeks. We found a statistically significant decrease in thyroid volume (p=0.043) and serum thyroid stimulating hormone (TSH) levels (p=0.007), whereas serum ATPO. ATGl, fT4, fT3, CEA and calcitonin levels did no change with 6 months of exenatide treatment. There were no significant differences in the size and appearance of the thyroid nodules with treatment. The thyroid volume decrease was not correlated with TSH, body mass index and HbA1c reduction. CONCLUSION: Exenatide treatment for 6 months decreased serum TSH levels and thyroid volume, but had no effect on thyroid nodules and serum CEA and calcitonin levels.

Iodine status of 8 to 10 years old children within 20 years following compulsory salt iodization policy in Shanghai, China.

BACKGROUND: In 1996, Shanghai implemented universal salt iodization and has became the last provincial unit in China to carry out this intervention. In this study, we summarized achievements in past 20 years, to provide suggestions and evidence for the next stage of iodine supplementation. METHODS: This study summarized and analyzed monitoring data of children from 1997, 1999, 2005, 2011, 2014, and 2017 in Shanghai. In each monitoring year, 30 streets or towns were selected using the probability-proportional-to-size sampling technique. One primary school was selected from each street or town by a simple random sampling technique. From each school, 40 children aged 8 to 10 years were randomly selected. The number of children was divided equally by sex and age. RESULTS: In 1997, 1999, 2005, 2011, 2014, and 2017, median urinary iodine (MUI) was 227.5 µg/L, 214.3 µg/L, 198.1 µg/L, 181.6 µg/L, 171.4 µg/L, and 183.0 µg/L, goiter rate was 3.07, 0.40, 0.08, 0.08, 0.86, and 1.90%, and median thyroid volume (MTvol) was 2.9 mL, 1.2 mL, 2.4 mL, 1.0 mL, 1.8 mL, and 2.8 mL, respectively. There was a linear correlation between goiter rate and median thyroid volume (MTvol) (r = 0.95, P = 0.014). Household salt iodine concentration (SIC) was dropping every monitoring (P < 0.05). There was a significant difference among different household SIC groups in MUI in 1999 and 2017, and in MTvol in 1999 (P < 0.05). No significant differences were detected in the other years. CONCLUSIONS: In Shanghai, the iodine status of 8 to 10 years old children is adequate. Household SIC have little effect on iodine status of children. Future studies should analyze the dietary sources of iodine, especially from pre-packaged and prepared-away-from-home foods or meals. The regular monitoring of iodine status is important to human health.

The association between thyroid hormone balance and thyroid volume in patients with Hashimoto thyroiditis.

While patients with large goitrous thyroid diseases often have a relatively high serum free triiodothyronine (FT3)/free thyroxine (FT4) ratio, athyreotic patients have a relatively low FT3/FT4 ratio. Here we investigated the relationship between thyroid hormone status and thyroid volume (TV) among a large number of euthyroid Hashimoto thyroiditis (HT) patients. We retrospectively enrolled 2,603 untreated HT patients who visited the Kuma hospital from 2012 to 2016, and divided them into four groups as per the TV: normal TV (<20 mL), slight goiter (20 ≤ TV < 50 mL), moderate goiter (50 ≤ TV < 80 mL), and the large goiter group (≥80 mL). Baseline characteristics and laboratory data of each group were compared to those of 1,554 control subjects. The association between FT3/FT4 ratio and TV among HT patients was then analyzed. We observed a change in laboratory parameters among 13 patients in the large goiter group who were prescribed levothyroxine (LT4) for reducing TV. Compared to normal subjects, the moderate and large goiter groups exhibited significantly higher serum FT3 levels, while all HT groups exhibited lower serum FT4 levels. Serum FT3/FT4 ratios showed a positive correlation with TV (r = 0.35, p < 0.01), which was independent of age, sex, body mass index, and TgAb and TSH levels. LT4 treatment lowered serum FT3 levels and FT3/FT4 ratios significantly. Our results indicated that HT patients with increased TV tended to present with high serum FT3, low FT4, and high FT3/FT4 ratios. The elevation of deiodinase activity may be an important factor affecting thyroid hormonal balance in such patients.

Thyroid Nodules Are More Prevalent in Subjects with Colon Polyps, Independent of Insulin Resistance.

OBJECTIVE: Colorectal polyps and thyroid nodules are common disorders linked to hyperinsulinemia and metabolic syndrome (Mets). The direct association between these two diseases is not clear. We aimed to analyze the prevalence of thyroid nodules in subjects with and without colorectal polyps. The secondary aim was to establish the prevalence of Mets and its parameters in both disorders and to determine if insulin resistance and hyperinsulinemia are common underlying pathophysiological mechanisms. SUBJECTS AND METHODS: One hundred and five subjects with colorectal polyps (71 males, 34 females) and 68 controls (28 males, 40 females) were enrolled. The parameters of Mets together with TSH, insulin, low-density lipoprotein cholesterol, and homeostasis model for assessment of insulin resistance levels were calculated. We performed thyroid ultrasonography in all participants. RESULTS: The prevalence of Mets was similar in the colorectal polyp and control groups (37.1 vs. 37.3%, p = 0.982). The prevalence of Mets was nonsignificantly higher in subjects with a documented thyroid nodule compared to subjects without a thyroid nodule (43.0 vs. 32.6%, p = 0.205). The prevalence of thyroid nodules in subjects with colorectal polyps was significantly higher than in subjects without polyps (52.9 vs. 35.3%, p = 0.017). Compared to subjects with no colorectal polyps, we established a significant increase in the odds of having thyroid nodules (OR 2.05; 95% CI: 1.097-3.860, p = 0.017). The presence of colorectal polyps and age in the adjusted model were established to be independent risk factors for having thyroid nodules (p = 0.025 and p = 0.007, respectively). CONCLUSION: These results may support the presence of other common mechanisms in the development of these two pathologies other than insulin resistance and hyperinsulinemia.

Changes in thyroid volume and insulin-like growth factor 1 in pre- and post-pubertal obese children.

BACKGROUND: There is a mutual dynamic interaction between thyroid volume (TV), insulin-like growth factor-1 (IGF-1), and body mass index (BMI). These covariates undergo a change with the transition into puberty. The heterogeneity of the variates and study populations complicate the evaluation of the role of pure pubertal effect. OBJECTIVE: The purpose of this study was to investigate the effect of puberty on IGF-1 and TV in a predetermined homogenous population such as obese children. SUBJECTS AND METHODS: Three hundred and eighty children (202 girls and 178 boys) aged between 6 and 18 were enrolled in this prospective study. The children were assigned to two groups according to their pubertal status, i.e., prepubertal (n = 169) and postpubertal (n = 211). According to age and sex, the obese group (n = 222) was made up of children at and above the 95th percentile, and the control group (n = 158) of children under the 85th percentile. The following parameters were evaluated in all children: BMI, pubertal status, TV, and serum IGF-1, IGFBP-3, and IGF-1:IGFBP-3 molar ratio. RESULTS: In comparison to the prepubertal obese group, the obese group at Tanner stage 2 had a larger mean TV (P = 0.008) and higher IGF-1 level (P = 0.033). There was a positive correlation between IGF-1 and TV both in the prepubertal and pubertal group (r169= 0.369, P = 0.001; r211= 0.316, P = 0.004, respectively), whereas there was no correlation between IGF-1 and BMI (r169= 0.99, P = 0.092; r211= 0.094, P = 0.088, respectively). CONCLUSION: This study showed that the TV and serum IGF-1 levels were increased in obese children in the early stage of puberty and that there was a positive correlation between these two variables in all children, which shows the specific effect of the early stage of puberty on the increase in TV and IGF-1 levels and suggests that increased TV is associated with the increase in IGF-1 levels in a homogenous group such as obese children.

ASSOCIATIONS OF THYROID VOLUME AND FUNCTION WITH CHILDHOOD OBESITY.

CONTEXT: The links between obesity and thyroid function or thyroid volume in children are still controversial with limited available data. OBJECTIVE: This study aimed to examine thyroid function and volume in obese Turkish school-age children in comparison to normal-weight children. DESIGN: Cross-sectional study. SUBJECTS AND METHODS: One hundred obese children (47 boys, 53 girls; mean age 10.34±2.79 years) with a body mass index (BMI) above 95th percentile, and 100 normal-weight children (42 boys, 58 girls; 10.34±2.79 years) were included. The study parameters were BMI z score (Z-BMI), body surface area (BSA), thyroid volume, free thyroxine (fT4) and thyroid stimulating hormone (TSH) levels. RESULTS: The mean TSH and fT4 levels did not show a significant difference between obese and normal-weight children (p>0.05). The mean thyroid volume was higher in obese children (6.46±5.84 and 4.64±1.44, respectively; p=0.043). fT4 correlated negatively with Z-BMI in both normal-weight and obese children (r=-0.285, p=0.004 and r=-0.289, p=0.004, respectively). Thyroid volume, on the other hand, correlated positively with Z-BMI, again in both normal-weight and obese children (r=0.657, p<0.001 and r=0.444, p<0.001, respectively). Similar associations were found for BSA. CONCLUSIONS: Thyroid volume correlated positively and fT4 correlated negatively with Z-BMI and BSA, in both obese and normal-weight school-age children, whereas TSH appears to be independent of these parameters.

The role of functional thyroid capacity in pituitary thyroid feedback regulation.

BACKGROUND: Thyroid feedback regulation and equilibria between thyroid hormones differ in the presence or absence of a functioning thyroid remnant. MATERIALS AND METHODS: This study examines the relationship between the sensitivity of TSH feedback and thyroid capacity in untreated patients with thyroid autoimmune disease (n = 86) and healthy controls (n = 271). Functional capacity was estimated at maximum TSH stimulation, and pituitary TSH response was FT4-standardised with two established indices, the TSH index and the thyrotroph thyroid hormone resistance index. RESULTS: The two indices correlated inversely with thyroid volume and functional thyroid capacity. Relationships were shifted upwards in patients with thyroid autoimmune disease. This positioned patients with thyroid autoimmune disease predominantly at the lower capacity range and upper part of TSH index. The relationship was modulated by serum FT3 concentrations, shifting 0.19 [95%CI: 0.12, 0.26] mIU/L per pmol FT3 increase. FT3 correlated with TSH index in total group ( τ  = 0.09, P = 0.009) and both subgroups. FT3 levels were maintained despite a substantial capacity loss by progressively increasing conversion rates of T3 from T4, only collapsing at capacities below <1.5 pmol/s. CONCLUSION: Functional thyroid capacity and preferential T3 generation are essential elements in adjusting the sensitivity of hypothalamic-pituitary-thyroid feedback control and balancing system equilibria. This suggests that the indirect regulatory role of glandular T3 co-secretion exceeds its quantitative contribution to the thyroid hormone pool. Implications for clinical practice extend to the diagnostic use of TSH in patients with impaired thyroid reserve.