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The effect of a ketogenic diet versus a high-carbohydrate, low-fat diet on sleep, cognition, thyroid function, and cardiovascular health independent of weight loss: study protocol for a randomized controlled trial.
Iacovides, S, Meiring, RM
Trials. 2018;(1):62
Abstract
BACKGROUND Many physiological health benefits observed after following a ketogenic diet (KD) can be attributed to the associated weight loss. The KD has become more prominent as a popular health choice, not only in obese/overweight individuals, but also in healthy adults. The study aims to determine the effects of a KD, independent of weight loss, on various aspects of physiological health including: sleep, thyroid function, cognition, and cardio-metabolic health. The study will also aim to determine whether a change in basal metabolic rate may be associated with any changes observed. METHODS Twenty healthy men and women between 18 and 50 years of age will take part in this study. In a randomized controlled, cross-over design, participants will follow two isocaloric diets: a high-carbohydrate, low-fat diet (55% CHO, 20% fat, 25% protein) and a KD (15% CHO, 60% fat, 25% protein). Each dietary intervention will last for a minimum of 3 weeks, with a 1-week washout period in between. Before and after each diet, participants will be assessed for sleep quality, cognitive function, thyroid function, and basal metabolic rate. A blood sample will also be taken for the measurement of cardio-metabolic and immune markers. DISCUSSION The present study will help in understanding the potential effects of a KD on aspects of physiological health in healthy adults, without the confounding factor of weight loss. The study aims to fill a significant void in the academic literature with regards to the benefits and/or risks of a KD in a healthy population, but will also explore whether diet-related metabolic changes may be responsible for the changes observed in physiological health. TRIAL REGISTRATION Pan African Clinical Trial Registry ( www.pactr.org ), trial number: PACTR201707002406306 . Registered on 20 July 2017.
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2.
Dietary Selenium Intake and Subclinical Hypothyroidism: A Cross-Sectional Analysis of the ELSA-Brasil Study.
Andrade, GRG, Gorgulho, B, Lotufo, PA, Bensenor, IM, Marchioni, DM
Nutrients. 2018;(6)
Abstract
Selenium (Se) participates in several enzymatic reactions necessary for regulating the homeostasis of thyroid hormones. We aimed to analyze the association between dietary Se intake and subclinical hypothyroidism. Baseline data from the Longitudinal Study of Adult Health (Estudo Longitudinal de Saúde do Adulto-ELSA-Brasil) in Brazil were analyzed, with a final sample size of 14,283 employees of both sexes aged 35⁻74 years. Dietary data was collected using a previously validated food frequency questionnaire. Subclinical hypothyroidism was categorized as thyroid-stimulating hormone levels of >4.0 IU/mL and free prohormone thyroxine levels within normal limits, without administering drugs for thyroid disease. A multiple logistic regression model was used to assess the relationship between the presence of subclinical hypothyroidism and tertiles of Se consumption. The prevalence of subclinical hypothyroidism in the study sample was 5.4% (95% confidence interval [CI], 3.8⁻7.0%). Compared with the first tertile of Se intake, the second (odds ratio [OR], 0.79; 95% CI, 0.65⁻0.96%) and third (OR, 0.72; 95% CI, 0.58⁻0.90%) tertiles were inversely associated with subclinical hypothyroidism, however further research is needed to confirm the involvement of Se in subclinical hypothyroidism using more accurate methodologies of dietary assessment and nutritional status to evaluate this relationship.
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Congenital Hypothyroidism.
Wassner, AJ
Clinics in perinatology. 2018;(1):1-18
Abstract
Congenital hypothyroidism is common and can cause severe neurodevelopmental morbidity. Prompt diagnosis and treatment are critical to optimizing long-term outcomes. Universal newborn screening is an important tool for detecting congenital hypothyroidism, but awareness of its limitations, repeated screening in high-risk infants, and a high index of clinical suspicion are needed to ensure that all affected infants are appropriately identified and treated. Careful evaluation will usually reveal the etiology of congenital hypothyroidism, which may inform treatment and prognosis. Early and adequate treatment with levothyroxine results in excellent neurodevelopmental outcomes for most patients with congenital hypothyroidism.
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4.
Bilateral Keratoconus Induced by Secondary Hypothyroidism After Radioactive Iodine Therapy.
Lee, R, Hafezi, F, Randleman, JB
Journal of refractive surgery (Thorofare, N.J. : 1995). 2018;(5):351-353
Abstract
PURPOSE To present a case of new-onset, bilateral, rapidly progressive keratoconus induced by secondary hypothyroidism after radioactive iodine therapy during the sixth decade of life that was successfully treated with corneal cross-linking. METHODS Case report and literature review. RESULTS A 53-year-old woman with no ocular complaints but with a history of Graves' disease and thyrotoxicosis was treated with radioactive iodine therapy and oral levothyroxine for secondary acquired hypothyroidism 3 years prior. Initially, uncorrected distance visual acuity (UDVA) was 20/40 and corrected distance visual acuity (CDVA) was 20/25 in both eyes. Over the following 3 years, the patient developed worsening UDVA and CDVA, with increasing manifest astigmatism of greater than 7.00 diopters (D) in the right eye and 4.75 D in the left eye, with corneal thinning and focal steepening and was diagnosed as having bilateral progressive keratoconus. The patient underwent sequential corneal cross-linking with resultant postoperative CDVA of 20/20 and reduced maximum keratometry and manifest astigmatism in both eyes. The patient's thyroid levels were within normal limits throughout the clinical course. CONCLUSIONS This case provides evidence of the relationship between keratoconus development and thyroid gland dysfunction. The pathophysiology of this relationship has yet to be completely elucidated, but elevated levels of thyroxine in the aqueous humor and tear film and thyroxine receptors in the cornea likely play a role. Screening topographies for patients with thyroid gland dysfunction may be of value for these higher risk patients. [J Refract Surg. 2018;34(5):351-353.].
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Early Determinants of Thyroid Function Outcomes in Children with Congenital Hypothyroidism and a Normally Located Thyroid Gland: A Regional Cohort Study.
Saba, C, Guilmin-Crepon, S, Zénaty, D, Martinerie, L, Paulsen, A, Simon, D, Storey, C, Dos Santos, S, Haignere, J, Mohamed, D, et al
Thyroid : official journal of the American Thyroid Association. 2018;(8):959-967
Abstract
BACKGROUND An increase in the incidence of congenital hypothyroidism (CH) with a normally located gland has been reported worldwide. Affected individuals display transient or permanent CH during follow-up in childhood. This study aimed to determine the prevalence of transient CH and to investigate the possibility of distinguishing between transient and permanent CH in early infancy. METHODS This observational cohort study included all patients identified by systematic neonatal screening for CH in the northern Parisian region between 2002 and 2012 and treated for CH with a normally sited gland. A standardized data collection form was completed prospectively at diagnosis. Patients were classified during follow-up as having transient or permanent CH. RESULTS Of the 92 patients initially treated for CH with a normally located gland during the neonatal period, 49 (54%) had a transient form of CH after the cessation of levothyroxine (LT4) treatment at 1.5 (0.6-3.2) years of age. Multivariate analysis revealed that transient CH was associated with a lower likelihood of having a first-degree family history of CH (p = 0.03) and a lower LT4 dose at six months of age (p = 0.03) than permanent CH. Sex, ethnicity, neonatal problems (e.g., prematurity, being small for gestational age, and/or neonatal distress), iodine status, coexisting malformations, initial CH severity, and thyroid morphology at diagnosis had no effect. Receiver operating characteristics curve analysis showed that a cutoff of 3.2 μg/kg/day for LT4 dose requirement at six months of age had a sensitivity of 71% and a specificity of 79% for predicting transient CH, with values below this threshold considered predictive of transient CH. CONCLUSION In patients with CH and a normally located gland, these findings highlight the need to evaluate LT4 dose requirements early, at six months of age, particularly in patients with no family history of CH, for early identification of the approximately 50% of patients for whom treatment should be stopped.
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Longitudinal Trajectories of Gestational Thyroid Function: A New Approach to Better Understand Changes in Thyroid Function.
Pop, V, Broeren, M, Wijnen, H, Endendijk, J, van Baar, A, Wiersinga, W, Williams, GR
The Journal of clinical endocrinology and metabolism. 2018;(8):2889-2900
Abstract
CONTEXT Most studies of thyroid function changes during pregnancy use a cross-sectional design comparing means between groups rather than similarities within groups. OBJECTIVE Latent class growth analysis (LCGA) is a novel approach to investigate longitudinal changes that provide dynamic understanding of the relationship between thyroid status and advancing pregnancy. DESIGN Prospective observational study with repeated assessments. SETTING General community. PATIENTS Eleven hundred healthy women were included at 12 weeks' gestation. MAIN OUTCOME MEASURES The existence of both free T4 (fT4) and TSH trajectories throughout pregnancy determined by LCGA. RESULTS LCGA revealed three trajectory classes. Class 1 (n = 1019; 92.4%), a low increasing TSH reference group, had a gradual increase in TSH throughout gestation (from 1.1 to 1.3 IU/L). Class 2 (n = 30; 2.8%), a high increasing TSH group, displayed the largest increase in TSH (from 1.9 to 3.3 IU/L). Class 3 (n = 51; 4.6%), a decreasing TSH group, had the largest fall in TSH (from 3.2 to 2.4 IU/L). Subclinical hypothyroidism at 12 weeks occurred in up to 60% of class 3 women and was accompanied by elevated thyroid peroxidase antibodies (TPO-Ab) titers (50%) and a parental history of thyroid dysfunction (23%). In class 2, 70% of women were nulliparous compared with 46% in class 1 and 49% in class 3. CONCLUSIONS LCGA revealed distinct trajectories of longitudinal changes in fT4 and TSH levels during pregnancy in 7.4% of women. These trajectories were correlated with parity and TPO-Ab status and followed patterns that might reflect differences in pregnancy-specific immune tolerance between nulliparous and multiparous women.
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The role of functional thyroid capacity in pituitary thyroid feedback regulation.
Hoermann, R, Midgley, JEM, Larisch, R, Dietrich, JW
European journal of clinical investigation. 2018;(10):e13003
Abstract
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.
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Horner syndrome as a complication after thyroid microwave ablation: Case report and brief literature review.
Zhang, X, Ge, Y, Ren, P, Liu, J, Chen, G
Medicine. 2018;(34):e11884
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Abstract
RATIONALE Horner's syndrome (HS) can present as a complication of thyroid surgery, particularly after thyroid microwave ablation (MWA). HS presents clinically with eyelid ptosis, miosis, enophthalmos, anhidrosis, and vascular dilatation, all of which result from a damaged oculosympathetic chain. We aimed to try to avoid such devastating symptoms in future cases by exploring reasons for the destruction of the cervical sympathetic trunk. PATIENT CONCERNS HS has previously been reported in the literature as a complication of thyroid surgery. Here, we report the case of a 44-year-old female patient who presented with miosis and eyelid ptosis following thyroid MWA. DIAGNOSES This patient was subsequently diagnosed with HS. INTERVENTIONS Mecobalamin was administered immediately. OUTCOMES After 5 months of follow up, the patient's miosis and ptosis was incompletely relieved. LESSONS Although HS is a rare complication of thyroid MWA, surgeons must be aware of the anatomic relationship of the cervical sympathetic trunk and thyroid gland with adjacent structures. Moreover, we hope this case presentation enables surgeons to take measures to minimize the possibility of oculosympathetic damage. Long-term follow up and comprehensive assessments are important for the patient's prognosis.
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Impact of Thyroid Autoimmunity on Thyroid Function in 12-year-old Children With Celiac Disease.
Norström, F, van der Pals, M, Myléus, A, Hammarroth, S, Högberg, L, Isaksson, A, Ivarsson, A, Carlsson, A
Journal of pediatric gastroenterology and nutrition. 2018;(1):64-68
Abstract
OBJECTIVES Celiac disease (CD) is associated with thyroid autoimmunity and other autoimmune diseases. Data are, however, lacking regarding the relationship between thyroid autoimmunity and thyroid function, especially in regard to CD. Our aim was to investigate the impact of thyroid autoimmunity on thyroid function in 12-year-old children with CD compared to their healthy peers. METHODS A case-referent study was conducted as part of a CD screening of 12-year-olds. Our study included 335 children with CD and 1695 randomly selected referents. Thyroid autoimmunity was assessed with antibodies against thyroid peroxidase (TPOAb). Thyroid function was assessed with thyroid-stimulating hormone and free thyroxine. RESULTS TPOAb positivity significantly increased the risk of developing hypothyroidism in all children. The odds ratios (with 95% confidence intervals) were 5.3 (2.7-11) in healthy 12-year-olds, 10 (3.2-32) in screening-detected CD cases, 19 (2.6-135) in previously diagnosed CD cases, and 12 (4.4-32) in all CD cases together. Among children with TPOAb positivity, hypothyroidism was significantly more common (odds ratio 3.1; 95% CI 1.03-9.6) in children with CD (10/19) than in children without CD (12/46). CONCLUSIONS The risk of thyroid dysfunction due to thyroid autoimmunity is larger for those with CD than their healthy peers. Our study indicates that a gluten-free diet does not reduce the risk of thyroid dysfunction. Further studies are required for improved understanding of the role of the gluten-free diet for the risk of autoimmune diseases in children with CD.
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Effect of iodinated contrast medium on thyroid function: a study in children undergoing cardiac computed tomography.
Belloni, E, Tentoni, S, Puci, MV, Avogliero, F, Della Latta, D, Storti, S, Alberti, B, Bottoni, A, Bortolotto, C, Fiorina, I, et al
Pediatric radiology. 2018;(10):1417-1422
Abstract
BACKGROUND Few studies, and with conflicting results, have evaluated the potential effects of iodinated contrast media on children's thyroid function. OBJECTIVE To investigate the effects of iodinated contrast medium on thyroid function in neonates, infants and young children with congenital heart disease undergoing cardiac computed tomography (CT). MATERIALS AND METHODS We retrospectively evaluated 10 neonates (group 1) and 23 infants and young children (group 2) without thyroid or renal disease for serum levels of thyroid-stimulating hormone, free triiodothyronine and free thyroxine before contrast-enhanced cardiac CT, 48 h after CT and at discharge from the hospital. Cardiac CT was performed with intravenous administration of 1.14±0.17 mL/kg of body weight of iopromide (containing 370 mg of iodine/mL). RESULTS Group 1 had a reduction of thyroid-stimulating hormone from baseline to 48 h post injection (P=0.002). Group 2 had a reduction of thyroid-stimulating hormone median levels from baseline to 48 h post injection and an increase from 48 h to discharge (P=0.0005 and P=0.0001, respectively). CONCLUSION Intravenous iodinated contrast medium in children with congenital heart disease caused transient thyroid-stimulating hormone decrease 48 h after CT, with thyroid-stimulating hormone returning to normal range at discharge.