Cholestyramine Use for Rapid Reversion to Euthyroid States in Patients with Thyrotoxicosis

Cholestyramine (CS) is an ion exchange resin, which binds to iodothyronines and would lower serum thyroid hormone level. The use of CS added to conventional antithyroid drugs to control thyrotoxicosis has been applied since 1980's, and several studies indicate that using CS in combination with methimazole (MZ) produces a more rapid decline in serum thyroid hormones than with only MZ treatment. Our recent retrospective review of five patients taking high dose MZ and CS, compared to age-, gender-, initial free thyroxine (T4) level-, and MZ dose-matched 12 patients with MZ use only, showed more rapid decline of both free T4 and triiodothyronine levels without more adverse events. CS could be safely applicable short-term adjunctive therapy when first-line antithyroid medications are not enough to adequately control severe thyrotoxicosis or side effects of antithyroid drug would be of great concern

Sex differences in risk factors for subclinical hypothyroidism

Objective: To investigate the prevalence of subclinical hypothyroidism (SCH) in Korean adults and identify the risk factors for the occurrence of SCH by sex. Design and methods: This study used data from the Sixth Korea National Health and Nutrition Examination Survey (KNHANES VI), a cross-sectional, nationally representative survey, which comprises a health interview survey, a health examination survey and a nutrition survey. To examine SCH, the reference range of thyroid-stimulating hormone (TSH) was defined using both the range provided by the test kit manufacturer (SCH-M) and a population-based range (SCH-P). We investigated the prevalence of SCH and its risk factors by sex using both reference ranges. Results: The prevalence of SCH in Koreans according to SCH-M (0.35–5.5 μIU/mL) was 5.6%, and 3.3% with SCH-P (0.62–6.68 μIU/mL). For men, smoking significantly reduced the incidence of SCH, positive anti-thyroid peroxidase antibody (TPOAb) significantly increased the risk of SCH, and in an adjusted model, the risk of SCH in all quartiles increased as the urine iodine creatinine ratio (UICR) quartile increased. For women, positive TPOAb was confirmed as a risk factor for SCH, as was the highest UICR quartile. Furthermore, the odds ratio for SCH in urban vs rural residence was 1.78. Conclusions: The prevalence rates of SCH were similar to those reported in the literature and previously known risk factors were confirmed using both TSH reference ranges. The notable findings from this study are that the increased risk of SCH with increased iodine intake was more marked in men than in women and that residential area may be a risk factor for SCH in women

Photoacoustic analysis of thyroid cancer in vivo: a pilot study

Thyroid cancer is one of the most prevalent cancers. About 3-8% of the people in the United States have thyroid nodules, and 5-15% of these nodules are malignant. Fine-needle aspiration biopsy (FNAB) is a standard procedure to diagnose malignity of nodules. However, about 10-20% of FNABs produce indeterminable results, which leads to repeat biopsies and unnecessary surgical operations. We have explored photoacoustic (PA) imaging as a new method to identify cancerous nodules. In a pilot study to test its feasibility, we recruited patients with thyroid nodules (currently 36 cases with 21 malignant and 15 benign nodules), acquired in vivo PA and ultrasound (US) images of the nodules in real time using a recently-developed clinical PA/US imaging system, and analyzed the acquired data offline. The preliminary results show that malignant and benign nodules could be differentiated by utilizing their PA amplitudes at different excitation wavelengths. This is the first in vivo PA analysis of thyroid nodules. Although a larger-scale study is needed for statistical significance, the preliminary results show the good potential of PA imaging as a non-invasive tool for triaging thyroid cancer.1

High Normal Range of Free Thyroxine is Associated with Decreased Triglycerides and with Increased High-Density Lipoprotein Cholesterol Based on Population Representative Data

Background: We aimed to evaluate the association between thyroid hormone (free thyroxine, free T4) level and lipid profiles in nationally representative data. Methods: This study was based on cross-sectional survey data from the sixth Korea National Health and Nutrition Examination Survey IV. After exclusion of subjects with a history of thyroid disease or abnormal thyroid function test and those on medication for dyslipidemia and/or cardiovascular disease, a total of 3548 subjects were included in the study. Results: There was a significant decrease in serum triglyceride levels and increase in serum high-density lipoprotein (HDL) cholesterol levels with high free T4 quartiles after adjustment for confounding factors (p for trend = 0.001 and p for trend = 0.014, respectively). Risk of hypertriglyceridemia was significantly decreased (odds ratio of 0.72 (95% confidential interval 0.53–0.98)) in the highest free T4 quartile compared to the lowest free T4 quartile, p = 0.044). Conclusions: Serum free T4 levels within normal range negatively correlated with serum triglyceride level and positively correlated with HDL-cholesterol level. Therefore, a close surveillance in terms of lipid profiles could be considered in subjects with low normal serum free T4 levels

Elastography Can Effectively Decrease the Number of Fine Needle Aspiration Biopsies on Patients with Calcified Thyroid Nodules

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Association between Sleep Duration and Subclinical Thyroid Dysfunction Based on Nationally Representative Data

Background: Sleep duration is an identified risk factor for adverse health outcomes. As the endocrine system is closely intertwined with sleep duration and quality, the association between endocrine dysfunction and sleep has been evaluated. Thyroid function, particularly that related to thyrotropin (TSH), is also known to be influenced by the sleep/awake status and circadian rhythm. Additionally, a link between sleep duration and autoimmunity, which is a common cause of thyroid dysfunction, has been suggested; however, depending on the sleep deprivation method used in studies, the effects of sleep on thyroid function vary. The relationship between subclinical thyroid dysfunction and sleep duration is poorly documented. Thus, to elucidate the impact of sleep on thyroid function, we investigated the association of subclinical thyroid dysfunction with sleep duration using representative data from the sixth Korea National Health and Nutrition Examination Survey, conducted from 2013 to 2015. Methods: In all, 4945 participants (2543 male and 2402 female) were included after excluding subjects using the following criteria: <19 years of age, free T4 level outside the normal range, history of thyroid disease, or incomplete data. The population was classified into three groups: short sleeper (<7 h/day), normal sleeper (7–8 h/day), and long sleeper (>8 h/day). The odds ratio (OR) for subclinical hypothyroidism or hyperthyroidism according to sleep duration was evaluated. Results: The short, normal, and long sleeper groups consisted of 2097, 2514, and 334 subjects, respectively. On multiple logistic regression analysis, compared to normal sleepers, short sleepers showed a significantly increased risk of subclinical hyperthyroidism (OR 1.37, 95% confidential interval (CI) 1.02–1.84, p = 0.036), while the risk of subclinical hypothyroidism in short sleepers was not elevated. Comparing long sleepers to normal sleepers, the OR for subclinical hyperthyroidism and hypothyroidism was 1.79 (95% CI 1.12–2.86, p = 0.015) and 1.91 (95% CI 1.03–3.53, p = 0.039), respectively. Conclusions: Both shorter and longer sleep durations were associated with an increase in the risk of subclinical thyroid dysfunction compared to the optimal sleep duration. This analysis of representative population data shows that sleep duration could intertwine with thyroid function resulting in increased risk of subclinical thyroid dysfunction

A Significant Association of Upper Limb Muscle Strength with Thyroid Function in Overweight and Obese Population: A Study of the Sixth Korea National Health and Nutrition Examination Survey (KNHANES 2014-2015)

Background. As skeletal muscle is one of main targets of thyroid hormone signalling, an association of thyroid function and muscle strength could be expected. The aim of study is to evaluate the association of free thyroxine (FT4) and thyrotropin (TSH) with upper limb muscle strength, measured by hand grip strength, in subjects with normal FT4 from national representative data. The study utilized the sixth edition of the Korea National Health and Nutrition Examination Survey. After exclusion of subjects with FT4 level out of normal range, a history of thyroid disease or cerebral disease, restricted activity, and incomplete data, a total of 3503 were recruited (age range 19–80 years, 51% male). FT4 positively correlated with upper limb muscle strength (β coefficient = −12.84, p<0.001), while TSH did negatively (β coefficient = −0.37, p=0.002). After adjusting for confounding factors, statistical significance disappeared. However, among subjects with BMI above 23 kg/m2, a negative correlation of TSH with upper limb muscle strength was found in a younger age group (19–39 years old) (β coefficient = −0.56, p=0.021), while FT4 positively correlated with upper limb muscle strength (β coefficient = 3.24, p=0.019) in an older group (above 40 years old). In overweight and obese subjects, a significant association of thyroid function with upper limb muscle strength was observed in nation-wide representative data. High TSH in a younger group and low FT4 in an older group could be risk factors for decreased upper limb muscle strength in obese population

Parathyroid hormone and vitamin D are associated with the risk of metabolic obesity in a middle-aged and older Korean population with preserved renal function: A cross-sectional study.

In general, obesity is a major contributor to metabolic syndrome (MetS) and is associated with insulin resistance (IR). Metabolically obese but normal weight (MONW) individuals present metabolic abnormalities and features of MetS despite having a normal range of body mass index (BMI). In recent years, different subtypes of obesity have been introduced, including metabolically healthy obese (MHO) and metabolically obese obese (MOO). Also, it has been reported that vitamin D and parathyroid hormone (PTH) are possibly linked with MetS.In this study, we aimed to evaluate the association between serum 25(OH)D, serum PTH, and the risk of metabolic obesity in four subtypes using nationally representative survey data for a Korean population conducted between 2008 and 2010. Of the 29,235 Korean participants, 18,997 subjects aged under 50 years were excluded. Participants with diabetes (n = 1,520), renal insufficiency (glomerular filtration rate [GFR] < 45 ml/min/1.73 m2, chronic kidney disease [CKD] stage 3b, 4, and 5 according to KDOQI classification [1]) (n = 49), history of treatment for osteoporosis (n = 455), insufficient data (n = 1,613), and fasting time less than 8 hours prior to blood collection (n = 771) were excluded for analysis. Ultimately, 5,830 adults (2,582 men and 3,248 women) were eligible for the present study. And, subtypes of obesity were divided into four types: Metabolically healthy normal weight (MHNW), Metabolically healthy obese (MHO), Metabolically obese but normal weight (MONW), and Metabolically obese obese (MOO). Female subjects with metabolic obesity were more likely to have higher levels of PTH and Male subjects with metabolic health were more likely to have higher serum 25(OH)D levels.We concluded that a positive association between serum PTH concentration and metabolic obesity among female subjects and an inverse relationship between serum 25(OH)D levels and the risk of metabolic obesity were found among male subjects. Further prospective studies are necessary to explore the biological mechanisms underlying these sex-specific findings

Gender specific association of parathyroid hormone and vitamin D with metabolic syndrome in population with preserved renal function

Abstract The association of parathyroid hormone (PTH) and vitamin D with Metabolic syndrome (MetS) was evaluated using representative data from the Korean population. Data from 7004 subjects aged 50 or older with preserved renal function (excluding chronic kidney disease stage 3b to 5) who were included in the Korean National Health and Nutrition Examination Survey between 2008 and 2010 were analysed. Higher PTH levels (pg/ml) were observed in subjects with MetS than in those without MetS among both genders (60.1 (58.6–61.6) vs. 62.4 (60.7–64.2) in males p = 0.018, 60.7 (59.4–62.1) vs. 63.9 (62.4–65.6) in females, p < 0.001). For females, PTH levels were significantly higher in subjects with MetS than in those without MetS after adjustment for possible covariates. Lower 25(OH)D levels were significantly associated with MetS only in male subjects (p = 0.004). As the number of MetS components increased, a significant rise in PTH levels (p for trend 0.005 in males and 0.024 in females) and a decrease in 25(OH)D levels (p for trend < 0.001 in males and 0.053 in females) were observed. In conclusion, among subjects with preserved renal function, PTH levels were possibly associated with MetS in females, whereas vitamin D levels exhibited a possible link to MetS in males