• Safety and Health at Work
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• 제12권3호
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• pp.390-395
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• 2021

Background: Health-care providers typically undergo shift work and are subjected to increased stress. Night shift work may induce disturbed sleep cycles and circadian rhythm. The objective of this study was to explore if night shift workers (NSWs) show an increased risk of abnormal thyroid-stimulating hormone (TSH). Methods: We conducted a retrospective cohort study of 574 employees without thyroid disease and abnormal TSH at baseline who underwent annual check-ups between 2007 and 2016 in a medical center. NSWs were defined as those with working time schedules other than daytime hours. We calculated the incidence rate and estimated the adjusted hazard ratio (HR) for incident abnormal TSH and subclinical hypothyroidism compared with non-NSWs using a Cox regression model. Results: A total of 56 incident abnormal TSH cases and 39 subclinical hypothyroidism cases in NSWs were identified during 3000 person-years of follow-up. In models adjusted for age, sex, obesity, and working departments, we found no increased relative risk for incident abnormal TSH (HR: 0.72, 95% confidence interval: 0.33-1.60) or subclinical hypothyroidism (HR: 0.52, 95% confidence interval: 0.19-1.45) when comparing NSWs to non-NSWs; nor were incidence rates significantly different among exclusively medical employees after excluding administrative staff. Conclusion: In this hospital-based nine-year follow-up retrospective cohort study, NSWs were not associated with increased relative risk of incident abnormal TSH and subclinical hypothyroidism, in contrast to previous cross-sectional studies.

• Journal of Nutrition and Health
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• 제45권3호
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• pp.218-228
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• 2012

The prevalence rate of thyroid dysfunction (hypothyroidism and hyperthyroidism) has increased within the Korean population and seems to be affected by iodine dietary habits. Some studies reported that the prevalence of thyroid dysfunction increase both in the area of iodine deficiency and excess. In this study, we tried to discover the difference in iodine intake, anthropometric measurements, and blood parameters between male subjects with or without subclinical thyroid dysfunction. A total of 5,249 subjects (Euthyroid: 4706, SubHypo: 454, SubHyper: 89) were used in this study. There were no significant differences in BMI, body fat, visceral fat, waist circumference, SBP, DBP, total cholesterol, HDL-cholesterol, LDL-cholesterol, TG, fasting serum glucose, HbA1c, alcohol intake, however significant differences were noticed in both age and smoking status. Through a food frequency questionnaire (FFQ), iodine intake per day was estimated. The average iodine intake was similar (SubHypo $392.9{\pm}279.0{\mu}g$, Euthyroid $376.5{\pm}281.7{\mu}g$, SubHyper $357.3{\pm}253.8 {\mu}g$) among groups. The main source of iodine intake was eggs (52.8%, 54.2%, 52.4%) followed by milk (16.3%, 15.8%, 17.8%), then sea mustard & sea tangle (12.4%, 11.9%, 11.6%). The prevalence of subclinical hypothyroidism and subclinical hyperthyroidism was higher in subjects whose intake was higher than the recommended nutrient intake (RNI). These results suggest that the excess consumption of iodine intake may act as one of the risk factors regarding thyroid dysfunction in Korea. Therefore, an adequate amount of iodine intake is necessary in order to prevent subclinical thyroid dysfunction and clinical thyroid dysfunction.

• 성인간호학회지
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• 제22권1호
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• pp.80-89
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• 2010

Purpose: This paper has attempted to investigate the association between the subclinical thyroid function disorder caused by natural change in thyroid hormones or thyroid remedies and the incidence of CHD. Methods: Data was analyzed of 7,675 women who had undergone health examinations in a hospital in Gyeonggi-do between January 2007 and December 2008. The covariation of the coronary risk factors such as age, BMI, HbA1C, systolic blood pressure, LDL:HDL-cholesterol ratio, CRP, smoking and exercise were analyzed by using logistic regression analysis. Results: A significant increase in serum TSH was observed with higher age (F=26.91, p=.00). In terms of age, the risk of CHD started to gradually increase since the 40s and sharply since the 60s (${\chi}^2$=113.29, p=.00). The serum TSH was the most significant parameter influencing CHD (B=.12, p=.00). The risk of coronary heart disease was 3.12 times higher in the subclinical hypothyroidism group (OR=3.12) while no significant difference was observed in the subclinical hyperthyroidism group. Conclusion: Subclinical hypothyroidism may be an independent risk factors for CHD. A nurse nursing patients with thyroid disorder should be well informed of their state of subclinical thyroid function disorder and make efforts to extend their health expectancy.

• 대한한방내과학회지
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• 제39권4호
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• pp.645-661
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• 2018

Objectives: The aim of this paper was to aid Korean clinical practices for determining clinical and subclinical hypothyroidism and to identify further relevant studies by summarizing the present domestic clinical studies. Methods: The research consisted of a review of articles up to July, 2018 found by searching 'Hypothyroidism' and 'Hashimoto's thyroiditis' as keywords in five domestic electronic databases. Results: Only nine studies satisfied the selection criteria and were analyzed. These included six case reports, two controlled clinical trials, and one randomized controlled trial. Of these, Anjeonleejoong-tang was the most frequent herbal medicine used to treat hypothyroidism. Conclusions: Systematic and large-scale research studies are needed to standardize the guidelines for traditional Korean treatment of hypothyroidism.

• Clinical and Experimental Pediatrics
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• 제63권3호
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• pp.110-114
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• 2020

Background: Subclinical hypothyroidism (SH) is a common condition in obese children. However, its effect on glucose and lipid metabolism in obese children remains controversial. Purpose: The present study aimed to investigate the association between SH and metabolic parameters. Methods: A total of 215 obese children and adolescents aged 6-18 years were included in this retrospective cross-sectional study. The patients' anthropometric measurements such as thyrotropin (TSH), free thyroxine (fT4), fasting plasma glucose, and insulin levels, as well as homeostasis model assessment for insulin resistance (HOMA-IR) index, and lipid profiles were evaluated. The patients were allocated to the SH group (fT4 normal, TSH 5-10 mIU/L) (n=77) or the control group (fT4 normal, TSH<5 mIU/L) (n=138). The glucose and lipid metabolisms of the 2 groups were compared. Results: SH was identified in 77 of 215 patients (36%). Mean body mass index was similar in both groups. The mean serum insulin, HOMA-IR, and triglyceride (TG) levels were higher and the mean high-density lipoprotein cholesterol level was lower in the SH group than in the control group (P=0.007, P=0.004, P=0.01, and P=0.02, respectively). A positive correlation was observed between TSH level and insulin level, HOMA-IR, and TG level. Conclusion: SH was identified in some of the obese children and adolescents. A clear association was observed between SH, insulin resistance, and dyslipidemia in obese children.

• Journal of Nutrition and Health
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• 제55권2호
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• pp.250-262
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• 2022

Purpose: Elevated iodine intake is related to a higher prevalence of subclinical hypothyroidism (SCH). We investigated the short-term effect of dietary iodine restriction on thyroid function in patients with SCH with high iodine intakes. Methods: The iodine levels in 64 SCH patients with serum TSH levels from 4.0 to 10.0 mIU/L and normal serum fT4 levels (n = 64) were assessed using 24-hour urine iodine test results and iodine intake levels calculated using a semi-quantitative food frequency questionnaire. Dietary iodine restriction was not recommended for patients with an iodine intake in the normal range (group A, n = 13), but seaweed restriction was recommended for patients with high iodine intakes (group B, n = 33). Thyroid functions and iodine levels were rechecked after three months. Another eighteen patients were prescribed thyroid hormone replacement therapy according to clinical criteria. Results: Median baseline iodine intake for the 64 patients was 290.61 ㎍/day, and median 24-hour urine iodine was 33.65 µmol/g of creatinine. The major source of dietary iodine was seaweed, which accounted for 72.2% of median baseline intake. Urine iodine and calculated iodine intake levels were positively correlated with serum TSH levels (p < 0.001 and p = 0.027, respectively), and calculated iodine intakes were significantly correlated with urine iodine levels (p = 0.001). In group B, iodine restriction significantly decreased urine iodine (p = 0.042) and TSH levels (p = 0.004), and conversion to euthyroid status was achieved in 16 of the 33 patients (48.5%). Conclusion: Iodine intake and urine iodine levels are correlated with thyroid function in SCH patients, and dietary iodine restriction can aid functional thyroid recovery in patients with elevated iodine intakes.

• Clinical and Experimental Pediatrics
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• 제63권2호
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• pp.52-55
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• 2020

Background: Immunomodulatory properties of interferon (IFN) have been documented. It may induce autoimmune diseases such as autoimmune thyroiditis with hypo- or hyperthyroidism. In addition, it may impair thyroid hormone synthesis through affecting iodide organification in thyroid gland. Purpose: The aim of this study was to describe thyroid function tests disturbances in children with chronic hepatitis C (CHC) receiving pegylated interferon-alpha (PEG IFN-α) plus ribavirin. Methods: Fifty children with CHC virus infection who received combined pegylated interferon-alpha with ribavirin were selected. Other 50 apparently healthy children of matched age and sex (considered as control group) were selected. All children (100) were subject to liver function tests, virological studies, and follow-up of thyroid function test during and after the treatment course. Results: Our study showed that 28% of children received combined PEG IFN-α plus ribavirin showed subclinical hypothyroidism. After 24 weeks treatment with combined therapy of IFN plus ribavirin, the mean level of thyroid stimulating hormone (TSH) was 3.23±88 mU/mL, while TSH was 1.16±0.77 mU/mL before starting treatment. On the other hand, mean TSH was 1.09±0.92 mU/mL in normal control group. Conclusion: This study revealed an association between subclinical thyroid dysfunction and treatment with IFN-alpha and ribavirin in children. Further studies on larger number of patients and longer follow-up duration are recommended for further confirmation.

• 생물정신의학
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• 제20권4호
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• pp.151-158
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• 2013

Objectives To investigate the pattern of subclinical hypothyroidism (SCH) in patients with bipolar disorders managed by lithium or valproic acid. Methods The study participants were 106 patients with DSM-IV bipolar disorders receiving planned maintenance treatment at the Mood Disorders Clinic of Seoul National University Bundang Hospital (aged between 17 and 64, mean duration of follow-up = 875.65 days). Using the bipolar disorder registry, thyroid function data were analyzed to assess the frequency of and the risk factors for SCH in patients managed by lithium (n = 64) or valproic acid (n = 42) for more than 5 months. Results Overall frequencies of SCH were 20.3% (13/64) in the lithium group, 14.3% (6/42) in the valproic acid group, and between the two groups there is no difference (p = 0.43). No differences were observed in the potential risk factors for SCH between the two groups including age, sex, subtype of bipolar disorder, baseline TSH, and concomitant antipsychotic use. In cases with SCH, thyroid-stimulating hormone (TSH) showed a tendency to increase at 3 month after the initiation of lithium or valproic acid. A gradual increase in the number of patients showing SCH was found within the first 3 years of medication. Conclusions With regular monitoring and careful assessment, there was no difference in the risk of SCH between lithium and valproic acid maintenance. The risk of mood stabilizer-associated SCH may gradually increase within 3 years following the commencement of medication, thereby mandating close monitoring for the first 3 years of treatment. Further studies with large sample size would be needed to confirm these findings.

• Clinical and Experimental Reproductive Medicine
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• 제42권4호
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• pp.131-135
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• 2015

The thyroid hormones act on nearly every cell in the body. Moreover, the thyroid gland continuously interacts with the ovaries, and the thyroid hormones are involved in almost all phases of reproduction. Thyroid dysfunctions are relatively common among women of reproductive age, and can affect fertility in various ways, resulting in anovulatory cycles, high prolactin levels, and sex hormone imbalances. Undiagnosed and untreated thyroid disease can be a cause of subfertility. Subclinical hypothyroidism (SCH), also known as mild thyroid failure, is diagnosed when peripheral thyroid hormone levels are within the normal reference laboratory range, but serum thyroid-stimulating hormone levels are mildly elevated. Thyroid autoimmunity (TAI) is characterized by the presence of anti-thyroid antibodies, which include anti-thyroperoxidase and anti-thyroglobulin antibodies. SCH and TAI may remain latent, asymptomatic, or even undiagnosed for an extended period. It has also been demonstrated that controlled ovarian hyperstimulation has a significant impact on thyroid function, particularly in women with TAI. In the current review, we describe the interactions between thyroid dysfunctions and subfertility, as well as the proper work-up and management of thyroid dysfunctions in subfertile women.

• 대한의료기공학회지
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• 제20권1호
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• pp.85-103
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• 2020

Objective : A common treatment for hypothyroidism is to supplement the deficient hormones. However, taking hormone medication does not improve clinical symptoms or side effects, so it is necessary to develop other improved treatments. The purpose of this study is to report that the Korean medicine treatment along with Whidam's Gokgol(CV2) Sugi therapy has improved symptoms of hypothyroidism and related the level of TSH, free T4 after halting the use of levothyroxine. Methods : We employed Korean medicine treatment; herbal-medication(延齡固本丹 and 加減平胃散), acupuncture, and cupping therapy, and so forth. At the same time, we treated the patient with Whidam's Sugi therapy(especially, Gokgol Sugi therapy). We treated the patient more than five times a week for the first month and treated more than three times a week for the next three months. Since then, we have treated the patient once or twice a week. The patient took a total of four blood tests during her treatment in 2012 and 2017. Results : 1. Both TSH and free T4 levels and clinical symptoms were normalized for patient with hypothyroidism who stopped taking levothyroxine by treating the patient with Korean medicine treatment and Whidam's Sugi therapy. 2. The combination of Korean medicine treatment and Whidam's Sugi therapy was also used in the case of subclinical hypothyroidism patient. 3. The combination of Korean medicine treatment and Whidam's Sugi therapy for hypothyroidism lasted for five years, not just for a short period of time. Conclusions : The combination of Korean medicine treatment and Whidam's Sugi therapy(especially, Gokgol Sugi therapy) was effective in the treatment of hypothyroidism and it helped to normalize the level of TSH, free T4. It is hoped that further clinical research will continue in the future so that it can be used not only for hypothyroidism but also for other endocrine diseases.