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Huang PC, Chen HC, Leung SH, Lin YJ, Huang HB, Chang WT, Huang HI, Chang JW. Associations between paraben exposure, thyroid capacity, homeostasis and pituitary thyrotropic function in the general Taiwanese: Taiwan Environmental Survey for Toxicants (TEST) 2013. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:1288-1303. [PMID: 38038926 DOI: 10.1007/s11356-023-31277-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 11/24/2023] [Indexed: 12/02/2023]
Abstract
Several studies have suggested that some endocrine disruptors such as synthetic phenols, parabens and phthalates may disrupt thyroid hormone signaling and associated negative feed-backs with the central hypothalamic-pituitary-thyroid (HPT) axis. Therefore, we investigated urinary paraben and blood thyroid hormone levels in the Taiwanese population. Our sample comprised 264 adults (aged 18-97 years) and 75 minors (aged 7-17 years) from Taiwan Environmental Survey for Toxicants 2013. Urinary levels of methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP) were assessed. Hormones of particular interest include: thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4). We sought integrated parameters to describe the transfer of thyroid hormones in homeostatic models. The geometric mean urinary paraben levels of the adults were higher than those of the minors (adults vs. minors; MeP: 383 vs. 62.4 ng/mL; PrP: 109 vs. 8.00 ng/mL; EtP: 39.5 vs. 2.38 ng/mL, and BuP: 6.36 vs. 2.13 ng/mL). In the male adults, we discovered that 0.253% (p = 0.032), 0.256% (p = 0.041) and 0.257% (p = 0.037) decreases in the TSH, TSH/T4 and TSH/FreeT4 ratio was associated with 1% EtP increases, respectively. In the female minors, 0.093% (p = 0.044), 0.072% (p = 0.047) and 0.156 (p = 0.004) increases in the TSH ratios were associated with a 1% MeP, EtP and BuP increase, respectively. Moreover, 0.151% (p = 0.008) and 0.177% (p = 0.001) increases in TSH/T4 and TSH/free T4 ratios were associated with a BuP 1% increase, respectively. Finally, EtP was positively associated with SPINA-GT (β: 15.66, p = 0.036) in the male adults. By contrast, EtP were positively associated with Jostel's TSH index and sTSHI (β: 0.072, p = 0.049; β: 0.107, p = 0.049) in the female minors. The Taiwanese population is commonly exposed to parabens, which can potentially lead to alteration of thyroid hormone homeostasis.
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Affiliation(s)
- Po-Chin Huang
- National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
- Research Center for Precision Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Safety, Health and Environmental Engineering, National United University, Miaoli, Taiwan
| | - Hsin-Chang Chen
- Department of Chemistry, Tunghai University, Taichung, Taiwan
| | - Shih-Hao Leung
- Institute of Environmental and Occupational Health Sciences, School of Medicine, National Yang Ming Chiao Tung University, 155 Li-Nong Street, Sec. 2, Beitou, Taipei, 112, Taiwan
| | - Yu-Jung Lin
- National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Han-Bin Huang
- School of Public Health, National Defense Medical Center, Taipei, Taiwan
| | - Wan-Ting Chang
- National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Hsin-I Huang
- National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Jung-Wei Chang
- Institute of Environmental and Occupational Health Sciences, School of Medicine, National Yang Ming Chiao Tung University, 155 Li-Nong Street, Sec. 2, Beitou, Taipei, 112, Taiwan.
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D'Aurizio F, Kratzsch J, Gruson D, Petranović Ovčariček P, Giovanella L. Free thyroxine measurement in clinical practice: how to optimize indications, analytical procedures, and interpretation criteria while waiting for global standardization. Crit Rev Clin Lab Sci 2023; 60:101-140. [PMID: 36227760 DOI: 10.1080/10408363.2022.2121960] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Thyroid dysfunctions are among the most common endocrine disorders and accurate biochemical testing is needed to confirm or rule out a diagnosis. Notably, true hyperthyroidism and hypothyroidism in the setting of a normal thyroid-stimulating hormone level are highly unlikely, making the assessment of free thyroxine (FT4) inappropriate in most new cases. However, FT4 measurement is integral in both the diagnosis and management of relevant central dysfunctions (central hypothyroidism and central hyperthyroidism) as well as for monitoring therapy in hyperthyroid patients treated with anti-thyroid drugs or radioiodine. In such settings, accurate FT4 quantification is required. Global standardization will improve the comparability of the results across laboratories and allow the development of common clinical decision limits in evidence-based guidelines. The International Federation of Clinical Chemistry and Laboratory Medicine Committee for Standardization of Thyroid Function Tests has undertaken FT4 immunoassay method comparison and recalibration studies and developed a reference measurement procedure that is currently being validated. However, technical and implementation challenges, including the establishment of different clinical decision limits for distinct patient groups, still remain. Accordingly, different assays and reference values cannot be interchanged. Two-way communication between the laboratory and clinical specialists is pivotal to properly select a reliable FT4 assay, establish reference intervals, investigate discordant results, and monitor the analytical and clinical performance of the method over time.
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Affiliation(s)
- Federica D'Aurizio
- Department of Laboratory Medicine, University Hospital of Udine, Udine, Italy
| | - Jürgen Kratzsch
- Institute for Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital, University of Leipzig, Leipzig, Germany
| | - Damien Gruson
- Department of Clinical Biochemistry, Cliniques Universitaires St-Luc and Université Catholique de Louvain, Brussels, Belgium
| | - Petra Petranović Ovčariček
- Department of Oncology and Nuclear Medicine, University Hospital Center Sestre milosrdnice, Zagreb, Croatia
| | - Luca Giovanella
- Clinic for Nuclear Medicine and Competence Center for Thyroid Diseases, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Bellinzona, Switzerland.,Clinic for Nuclear Medicine and Thyroid Center, University and University Hospital of Zurich, Zurich, Switzerland
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Fitzgerald SP, Falhammar H. Redefinition of Successful Treatment of Patients With Hypothyroidism. Is TSH the Best Biomarker of Euthyroidism? Front Endocrinol (Lausanne) 2022; 13:920854. [PMID: 35784560 PMCID: PMC9243528 DOI: 10.3389/fendo.2022.920854] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 05/10/2022] [Indexed: 12/14/2022] Open
Abstract
In recent years evidence has accumulated supporting a revised view of the nature of euthyroidism and the biomarkers of thyroid function. Within the normal range, variations in thyroid hormone levels are associated with variations in clinical parameters and outcomes. There are therefore no readily identified individually specific optimum levels of thyroid hormones for any individual. Levels around the middle of the normal population range may best reflect euthyroidism. These levels may have evolutionary advantages on the basis that adverse outcomes often increase with divergence from such levels, and physiological processes tend to minimise such inter-individual and intra-individual divergence. In populations of predominantly untreated individuals, levels of thyroid hormones and in particular levels of free thyroxine (FT4) correlate more often with clinical parameters than do levels of thyrotropin (TSH). Levels of thyroid hormones may therefore be regarded as the best available biomarkers of euthyroidism and dysthyroidism. It follows that 'subclinical hypothyroidism' (normal FT4/raised TSH levels), rather than being an accurate marker of peripheral tissue hypothyroidism is more a marker of decreased thyroid reserve and prognosis. The recent evidence suggests that treatment of hypothyroxinemia, regardless of the TSH level, and monitoring therapy using FT4 and/or triiodothyronine levels, depending on the replacement regime, may result in more successful treatment of hypothyroidism than relying on thyrotropin levels for patient selection and subsequent treatment monitoring. The equivalents of mid-range levels of thyroid hormones (especially FT4), adjusted by individual comorbidity concerns, may be rational general replacement targets. These implications of the new evidence may create opportunities for novel trials of thyroid replacement therapy.
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Affiliation(s)
- Stephen P. Fitzgerald
- The Departments of General Medicine and Endocrinology, The Royal Adelaide Hospital, Adelaide, SA, Australia
- School of Medicine, The University of Adelaide, Adelaide, SA, Australia
| | - Henrik Falhammar
- Department of Endocrinology, Karolinska University Hospital, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Menzies School of Health Research and Royal Darwin Hospital, Tiwi, NT, Australia
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Hegedüs L, Bianco AC, Jonklaas J, Pearce SH, Weetman AP, Perros P. Primary hypothyroidism and quality of life. Nat Rev Endocrinol 2022; 18:230-242. [PMID: 35042968 PMCID: PMC8930682 DOI: 10.1038/s41574-021-00625-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/17/2021] [Indexed: 12/15/2022]
Abstract
In the 1970s, treatment with thyroid extract was superseded by levothyroxine, a synthetic L form of tetraiodothyronine. Since then, no major innovation has emerged for the treatment of hypothyroidism. The biochemical definition of subclinical hypothyroidism is a matter of debate. Indiscriminate screening for hypothyroidism has led to overdiagnosis and treatment initiation at lower serum levels of thyroid-stimulating hormone (TSH) than previously. Adverse health effects have been documented in individuals with hypothyroidism or hyperthyroidism, and these adverse effects can affect health-related quality of life (QOL). Levothyroxine substitution improves, but does not always normalize, QOL, especially for individuals with mild hypothyroidism. However, neither studies combining levothyroxine and liothyronine (the synthetic form of tri-iodothyronine) nor the use of desiccated thyroid extract have shown robust improvements in patient satisfaction. Future studies should focus not only on a better understanding of an individual's TSH set point (the innate narrow physiological range of serum concentration of TSH in an individual, before the onset of hypothyroidism) and alternative thyroid hormone combinations and formulations, but also on autoimmunity and comorbidities unrelated to hypothyroidism as drivers of patient dissatisfaction. Attention to the long-term health consequences of hypothyroidism, beyond QOL, and the risks of overtreatment is imperative.
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Affiliation(s)
- Laszlo Hegedüs
- Department of Endocrinology, Odense University Hospital, Odense, Denmark.
| | - Antonio C Bianco
- Section of Adult and Paediatric Endocrinology, Diabetes & Metabolism, Department of Medicine, University of Chicago, Chicago, IL, USA
| | | | - Simon H Pearce
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
- Department of Endocrinology, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Anthony P Weetman
- Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | - Petros Perros
- Department of Endocrinology, Royal Victoria Infirmary, Newcastle upon Tyne, UK
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Zhang Y, He DH, Jiang SN, Wang HL, Xu XH, Kong LR. Biological variation of thyroid function biomarkers over 24 hours. Clin Chim Acta 2021; 523:519-524. [PMID: 34762936 DOI: 10.1016/j.cca.2021.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/29/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022]
Abstract
BACKGROUND Thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free T3 (FT3), and free T4 (FT4) are used to diagnose thyroid diseases and monitor treatment effects. Reliable biological variation (BV) data is required to ensure accurate clinical decisions. METHODS Blood samples were collected from 31 healthy subjects at 00:00, 04:00, 08:00, 12:00, 16:00, and 20:00; each sample was analyzed twice for TSH, T3, T4, FT3, and FT4. After outlier exclusion, normality assessment, and variance homogeneity, sex-stratified BV, including within-subject (CVI) and between-subject (CVG), was defined using nested ANOVA. RESULTS Concentrations of five biomarkers were significantly different between sexes. The CVI and CVG estimates were 34.54% and 34.43% for TSH, 5.89% and 14.18% for T3, 4.48% and 14.96% for T4, 5.37% and 11.23% for FT3, and 3.57% and 8.03% for FT4, respectively. The individual indexes (IIs) of all the biomarkers (except TSH) were ≤ 0.63. Males had lower CVIs and IIs than females. CONCLUSION CVI estimates of all hormones, except TSH, were lower than those reported on the BV website, showing low IIs and differences between sexes. We provide updated data on the short-term BV of thyroid function biomarkers according to sex and complement BV data of thyroid function biomarkers.
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Affiliation(s)
- Yan Zhang
- Department of Clinical Laboratory, Traditional Chinese Medicine Hospital of Pidu District, Chengdu, China
| | - Da-Hai He
- Department of Clinical Laboratory, Traditional Chinese Medicine Hospital of Pidu District, Chengdu, China
| | - Shun-Ning Jiang
- Department of Clinical Laboratory, Traditional Chinese Medicine Hospital of Pidu District, Chengdu, China
| | - Hua-Li Wang
- Department of Clinical Laboratory, Traditional Chinese Medicine Hospital of Pidu District, Chengdu, China
| | - Xiao-Hua Xu
- Department of Clinical Laboratory, Traditional Chinese Medicine Hospital of Pidu District, Chengdu, China
| | - Li-Rui Kong
- Department of Clinical Laboratory, Traditional Chinese Medicine Hospital of Pidu District, Chengdu, China.
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Fitzgerald SP, Bean NG, Hennessey JV, Falhammar H. Thyroid testing paradigm switch from thyrotropin to thyroid hormones-Future directions and opportunities in clinical medicine and research. Endocrine 2021; 74:285-289. [PMID: 34449031 PMCID: PMC8497305 DOI: 10.1007/s12020-021-02851-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/12/2021] [Indexed: 12/26/2022]
Abstract
PURPOSE Recently published papers have demonstrated that particularly in untreated individuals, clinical parameters more often associate with thyroid hormone, particularly free thyroxine (FT4), levels than with thyrotropin (TSH) levels. Clinical and research assessments of the thyroid state of peripheral tissues would therefore be more precise if they were based on FT4 levels rather than on TSH levels. In this paper we describe implications of, and opportunities provided by, this discovery. CONCLUSIONS The FT4 level may be the best single test of thyroid function. The addition of free triiodothyronine (FT3) and TSH levels would further enhance test sensitivity and distinguish primary from secondary thyroid dysfunction respectively. There are opportunities to reconsider testing algorithms. Additional potential thyroidology research subjects include the peripheral differences between circulating FT4 and FT3 action, and outcomes in patients on thyroid replacement therapy in terms of thyroid hormone levels. Previously performed negative studies of therapy for subclinical thyroid dysfunction could be repeated using thyroid hormone levels rather than TSH levels for subject selection and the monitoring of treatment. Studies of outcomes in older individuals with treatment of high normal FT4 levels, and pregnant women with borderline high or low FT4 levels would appear to be the most likely to show positive results. There are fresh indications to critically re-analyse the physiological rationale for the current preference for TSH levels in the assessment of the thyroid state of the peripheral tissues. There may be opportunities to apply these research principles to analogous parameters in other endocrine systems.
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Affiliation(s)
- Stephen P Fitzgerald
- The Departments of General Medicine and Endocrinology, The Royal Adelaide Hospital, Adelaide, SA, South Australia.
- The University of Adelaide, School of Medicine, Adelaide, SA, Australia.
| | - Nigel G Bean
- School of Mathematical Sciences and ARC Centre of Excellence for Mathematical and Statistical Frontiers, University of Adelaide, Adelaide, SA, Australia
| | - James V Hennessey
- Division of Endocrinology, Department of Medicine Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Henrik Falhammar
- Department of Endocrinology, Karolinska University Hospital, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Menzies School of Health Research and Royal Darwin Hospital, DARWIN, NT, Australia
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Davis CQ, Hamilton R. Reference ranges for clinical electrophysiology of vision. Doc Ophthalmol 2021; 143:155-170. [PMID: 33880667 PMCID: PMC8494724 DOI: 10.1007/s10633-021-09831-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/16/2021] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Establishing robust reference intervals for clinical procedures has received much attention from international clinical laboratories, with approved guidelines. Physiological measurement laboratories have given this topic less attention; however, most of the principles are transferable. METHODS Herein, we summarise those principles and expand them to cover bilateral measurements and one-tailed reference intervals, which are common issues for those interpreting clinical visual electrophysiology tests such as electroretinograms (ERGs), visual evoked potentials (VEPs) and electrooculograms (EOGs). RESULTS The gold standard process of establishing and defining reference intervals, which are adequately reliable, entails collecting data from a minimum of 120 suitable reference individuals for each partition (e.g. sex, age) and defining limits with nonparametric methods. Parametric techniques may be used under some conditions. A brief outline of methods for defining reference limits from patient data (indirect sampling) is given. Reference intervals established elsewhere, or with older protocols, can be transferred or verified with as few as 40 and 20 suitable reference individuals, respectively. Consideration is given to small numbers of reference subjects, interpretation of serial measurements using subject-based reference values, multidimensional reference regions and age-dependent reference values. Bilateral measurements, despite their correlation, can be used to improve reference intervals although additional care is required in computing the confidence in the reference interval or the reference interval itself when bilateral measurements are only available from some of subjects. DISCUSSION Good quality reference limits minimise false-positive and false-negative results, thereby maximising the clinical utility and patient benefit. Quality indicators include using appropriately sized reference datasets with appropriate numerical handling for reporting; using subject-based reference limits where appropriate; and limiting tests for each patient to only those which are clinically indicated, independent and highly discriminating.
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Affiliation(s)
| | - Ruth Hamilton
- Department of Clinical Physics and Bioengineering, Royal Hospital for Children, NHS Greater Glasgow and Clyde, Glasgow, UK.
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
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Lado-Baleato Ó, Roca-Pardiñas J, Cadarso-Suárez C, Gude F. Modeling conditional reference regions: Application to glycemic markers. Stat Med 2021; 40:5926-5946. [PMID: 34396576 DOI: 10.1002/sim.9163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/07/2021] [Accepted: 07/29/2021] [Indexed: 12/31/2022]
Abstract
Many clinical decisions are taken based on the results of continuous diagnostic tests. Usually, only the results of one single test is taken into consideration, the interpretation of which requires a reference range for the healthy population. However, the use of two different tests, can be necessary in the diagnosis of certain diseases. This obliges a bivariate reference region be available for their interpretation. It should also be remembered that reference regions may depend on patient variables (eg, age and sex) independent of the suspected disease. However, few proposals have been made regarding the statistical modeling of such reference regions, and those put forward have always assumed a Gaussian distribution, which can be rather restrictive. The present work describes a new statistical method that allows such reference regions to be estimated with no insistence on the results being normally distributed. The proposed method is based on a bivariate location-scale model that provides probabilistic regions covering a specific percentage of the bivariate data, dependent on certain covariates. The reference region is estimated nonparametrically and the nonlinear effects of continuous covariates via polynomial kernel smoothers in additive models. The bivariate model is estimated using a backfitting algorithm, and the optimal smoothing parameters of the kernel smoothers selected by cross-validation. The model performed satisfactorily in simulation studies under the assumption of non-Gaussian conditions. Finally, the proposed methodology was found to be useful in estimating a reference region for two continuous diagnostic tests for diabetes (fasting plasma glucose and glycated hemoglobin), taking into account the age of the patient.
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Affiliation(s)
- Óscar Lado-Baleato
- Department of Statistics, Mathematical Analysis, and Optimization, Universidade de Santiago de Compostela, Galicia, Spain
| | - Javier Roca-Pardiñas
- Statistical Inference, Decision and Operations Research, Universidade de Vigo, Galicia, Spain
| | - Carmen Cadarso-Suárez
- Department of Statistics, Mathematical Analysis, and Optimization, Universidade de Santiago de Compostela, Galicia, Spain
| | - Francisco Gude
- Clinical Epidemiology Unit, Complexo Hospitalario de Santiago de Compostela, Galicia, Spain
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Zhou Y, Ke S, Wu K, Huang J, Gao X, Li B, Lin X, Liu X, Liu X, Ma L, Wang L, Wu L, Wu L, Xie C, Xu J, Wang Y, Liu L. Correlation between Thyroid Homeostasis and Obesity in Subclinical Hypothyroidism: Community-Based Cross-Sectional Research. Int J Endocrinol 2021; 2021:6663553. [PMID: 34135958 PMCID: PMC8179776 DOI: 10.1155/2021/6663553] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/26/2021] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE It remains unknown whether obesity has an effect on the pituitary-thyroid feedback control axis in subclinical hypothyroidism (SCH). We aimed to investigate the association of thyroid homeostasis with obesity in a SCH population. METHODS Our study consisted of a community-based and cross-sectional study from the Epidemiological Survey of Thyroid Diseases in Fujian Province, China. A total of 193 subjects with SCH (90 males and 103 females) without a history of treatment of thyroid disease, such as surgery, radiation, and thyroid hormone or antithyroid medication, were included in the present study. Indices of obesity, including body mass index (BMI), waist circumference (WC), and waist-height ratio (WHtR) were measured. RESULTS Our results showed that the secretory capacity of the thyroid gland (SPINA-GT) and Jostel's thyrotropin index (TSHI) were negatively correlated with BMI, WC, and WHtR, whereas the reciprocal of the thyrotroph thyroid hormone resistance index (TTSI-1) was positively correlated with BMI (all p < 0.05). After adjustment for age, sex, smoking, iodine status, and glucolipid metabolism, the associations between TSHI, TTSI (reciprocal transformation), and BMI still persisted (all p < 0.05). CONCLUSIONS These results suggest that low levels of thyroid homeostasis indexes may be associated with overall obesity in SCH, rather than central adiposity.
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Affiliation(s)
- Yu Zhou
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
- Department of Clinical Pharmacy and Pharmacy Administration, School of Pharmacy, Fujian Medical University, Fuzhou 350122, Fujian, China
| | - Sujie Ke
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Kejun Wu
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Jingze Huang
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Xuelin Gao
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Beibei Li
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Xiaoying Lin
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Xiaohong Liu
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Xiaoying Liu
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Li Ma
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Linxi Wang
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Li Wu
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Lijuan Wu
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Chengwen Xie
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Junjun Xu
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Yanping Wang
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
| | - Libin Liu
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, Fujian, China
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Fitzgerald SP, Bean NG, Falhammar H, Tuke J. Clinical Parameters Are More Likely to Be Associated with Thyroid Hormone Levels than with Thyrotropin Levels: A Systematic Review and Meta-Analysis. Thyroid 2020; 30:1695-1709. [PMID: 32349628 PMCID: PMC7757573 DOI: 10.1089/thy.2019.0535] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background: Though the functional states of other endocrine systems are not defined on the basis of levels of controlling hormones, the assessment of thyroid function is based on levels of the controlling hormone thyrotropin (TSH). We, therefore, addressed the question as to whether levels of thyroid hormones [free thyroxine (fT4), total triiodothyronine (TT3)/free triiodothyronine (fT3)], or TSH levels, within and beyond the reference ranges, provide the better guide to the range of clinical parameters associated with thyroid status. Methods: A PubMed/MEDLINE search of studies up to October 2019, examining associations of levels of thyroid hormones and TSH, taken simultaneously in the same individuals, with clinical parameters was performed. We analyzed atrial fibrillation, other cardiac parameters, osteoporosis and fracture, cancer, dementia, frailty, mortality, features of the metabolic syndrome, and pregnancy outcomes. Studies were assessed for quality by using a modified Newcastle-Ottawa score. Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed. A meta-analysis of the associations was performed to determine the relative likelihood of fT4, TT3/fT3, and TSH levels that are associated with the clinical parameters. Results: We identified 58 suitable articles and a total of 1880 associations. In general, clinical parameters were associated with thyroid hormone levels significantly more often than with TSH levels-the converse was not true for any of the clinical parameters. In the 1880 considered associations, fT4 levels were significantly associated with clinical parameters in 50% of analyses. The respective frequencies for TT3/fT3 and TSH levels were 53% and 23% (p < 0.0001 for both fT4 and TT3/fT3 vs. TSH). The fT4 and TT3/fT3 levels were comparably associated with clinical parameters (p = 0.71). More sophisticated statistical analyses, however, indicated that the associations with TT3/fT3 were not as robust as the associations with fT4. Conclusions: Thyroid hormones levels, and in particular fT4 levels, seem to have stronger associations with clinical parameters than do TSH levels. Associations of clinical parameters with TSH levels can be explained by the strong negative population correlation between thyroid hormones and TSH. Clinical and research components of thyroidology currently based on the measurement of the thyroid state by reference to TSH levels warrant reconsideration.
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Affiliation(s)
- Stephen P. Fitzgerald
- Department of General Medicine and Royal Adelaide Hospital, Adelaide, South Australia
- Department of Endocrinology, Royal Adelaide Hospital, Adelaide, South Australia
- School of Medicine, University of Adelaide, Adelaide, South Australia
| | - Nigel G. Bean
- School of Mathematical Sciences, University of Adelaide, Adelaide, South Australia
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, University of Adelaide, Adelaide, South Australia
| | - Henrik Falhammar
- Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Wellbeing and Chronic Preventable Diseases Division, Menzies School of Health Research and Royal Darwin Hospital, Tiwi, Australia
| | - Jono Tuke
- School of Mathematical Sciences, University of Adelaide, Adelaide, South Australia
- ARC Centre of Excellence for Mathematical and Statistical Frontiers, University of Adelaide, Adelaide, South Australia
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Tan Y, Gao L, Yin Q, Sun Z, Man X, Du Y, Chen Y. Thyroid hormone levels and structural parameters of thyroid homeostasis are correlated with motor subtype and disease severity in euthyroid patients with Parkinson's disease. Int J Neurosci 2020; 131:346-356. [PMID: 32186220 DOI: 10.1080/00207454.2020.1744595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Purpose: This study is to investigate the relationship between thyroid function and Parkinson's disease (PD).Materials and Methods: Totally 77 PD patients were included, who were divided into tremor-dominant-type (TDT), akinetic-rigid-type (ART) and mixed-type (MXT) subgroups. Parkinsonism severity and stage was assessed by modified H-Y stage. Thyroid-stimulating hormone (TSH), fT3 and fT4 levels were detected to analyze thyroid function. Parameters of thyroid homeostasis, including thyroid's secretory capacity (SPINA-GT), the total deiodinase activity (SPINA-GD) and Jostel's TSH index and the thyrotroph thyroid hormone sensitivity index (TTSI), were calculated and compared.Results: Thyroid hormone levels in PD patients were lower than normal controls. Patients with TDT/MXT had significantly higher fT4 level than those with ART. TSH levels were 1.73 ± 0.93 and 2.06 ± 1.04 ulU/ml for patients with TDT/MXT and ART, respectively. The patients in the TDT/MXT group had significantly lower SPINA-GD while significantly higher SPINA-GT than ART group. The fT3 level was significantly higher in early group than advanced group. TSH index in the early group was significantly higher than the advanced group. The fT4 level was negatively correlated with UPDRS motor score. Univariate and multivariable logistic regression analysis indicated that fT4 was positively correlated with PD motor subtype, which disappeared after adjusting for confounding factors. The fT3 level was negatively correlated with PD disease severity, even after adjusting for confounding factors. In female PD patients, fT4 level in TDT/MXT group was significantly higher than ART group. Male PD patients had higher fT4 levels in early patients than advanced patients. Percentage of patients exhibiting ART was decreased significantly in higher fT4 level subgroups. With the increase of TSH index and TTSI, the proportion of advanced PD patients gradually decreased. The proportion of PD patients with TDT/MXT motor subtype gradually increased with the quartiles of SPINA-GT.Conclusion: Thyroid hormone levels and structural parameters of thyroid homeostasis are correlated with motor subtype and disease severity in euthyroid patients with PD.
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Affiliation(s)
- Yinyin Tan
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Lei Gao
- The People Hospital of Huaiyin Jinan, Jinan, China
| | - Qingqing Yin
- Department of Geriatrics, Department of Geriatric Neurology, Shandong Provincial Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Zhanfang Sun
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Xiao Man
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Yifeng Du
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Yan Chen
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
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Challenges in Interpreting Thyroid Stimulating Hormone Results in the Diagnosis of Thyroid Dysfunction. J Thyroid Res 2019; 2019:4106816. [PMID: 31662841 PMCID: PMC6778876 DOI: 10.1155/2019/4106816] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/01/2019] [Indexed: 12/16/2022] Open
Abstract
The pituitary hormone, thyrotropin (TSH), is regarded as the primary biomarker for evaluating thyroid function and is useful in guiding treatment with levothyroxine for patients with hypothyroidism. The amplified response of TSH to slight changes in thyroid hormone levels provides a large and easily measured signal in the routine care setting. Laboratories provide reference ranges with upper and lower cutoffs for TSH to define normal thyroid function. The upper limit of the range, used to diagnose subclinical (mild) hypothyroidism, is itself a matter for debate, with authoritative guidelines recommending treatment to within the lower half of the range. Concomitant diseases, medications, supplements, age, gender, ethnicity, iodine status, time of day, time of year, autoantibodies, heterophilic antibodies, smoking, and other factors influence the level of TSH, or the performance of current TSH assays. The long-term prognostic implications of small deviations of TSH from the reference range are unclear. Correction of TSH to within the reference range does not always bring thyroid and other biomarkers into range and will not always resolve the patient's symptoms. Overt hypothyroidism requires intervention with levothyroxine. It remains important that physicians managing a patient with symptoms suggestive of thyroid disease consider all of the patient's relevant disease, lifestyle, and other factors before intervening on the basis of a marginally raised TSH level alone. Finally, these limitations of TSH testing mitigate against screening the population for the undoubtedly substantial prevalence of undiagnosed thyroid disease, until appropriately designed randomised trials have quantified the benefits and harms from this approach.
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Hoermann R, Midgley JEM, Larisch R, Dietrich JW. Individualised requirements for optimum treatment of hypothyroidism: complex needs, limited options. Drugs Context 2019; 8:212597. [PMID: 31516533 PMCID: PMC6726361 DOI: 10.7573/dic.212597] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 07/09/2019] [Accepted: 07/15/2019] [Indexed: 12/21/2022] Open
Abstract
Levothyroxine (LT4) therapy has a long history, a well-defined pharmacological profile and a favourable safety record in the alleviation of hypothyroidism. However, questions remain in defining the threshold for the requirement of treatment in patients with subclinical hypothyroidism, assessing the dose adequacy of the drug, and selecting the best treatment mode (LT4 monotherapy versus liothyronine [LT3]/LT4 combinations) for subpopulations with persisting complaints. Supplied as a prodrug, LT4 is enzymatically converted into the biologically more active thyroid hormone, triiodothyronine (T3). Importantly, tetraiodothyronine (T4) to T3 conversion efficiency may be impaired in patients receiving LT4, resulting in a loss of thyroid-stimulating hormone (TSH)-mediated feed-forward control of T3, alteration of the interlocking equilibria between serum concentrations of TSH, free thyroxine (FT4), and free triiodothyonine (FT3), and a decrease in FT3 to FT4 ratios. This downgrades the value of the TSH reference system derived in thyroid health for guiding the replacement dose in the treatment situation. Individualised conditionally defined setpoints may therefore provide appropriate biochemical targets to be clinically tested, together with a stronger focus on clinical presentation and future endpoint markers of tissue thyroid state. This cautionary note encompasses the use of aggregated statistical data from clinical trials which are not safely applicable to the individual level of patient care under these circumstances.
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Affiliation(s)
- Rudolf Hoermann
- Department for Nuclear Medicine, Klinikum Lüdenscheid, Paulmannshöherstr. 14, 58515 Lüdenscheid, Germany
| | | | - Rolf Larisch
- Department for Nuclear Medicine, Klinikum Lüdenscheid, Paulmannshöherstr. 14, 58515 Lüdenscheid, Germany
| | - Johannes W Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Buerkle-de-la-Camp-Platz 1, 44789 Bochum, Germany.,Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Alexandrinenstr. 5, 44791 Bochum, Germany
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Jonklaas J, Razvi S. Reference intervals in the diagnosis of thyroid dysfunction: treating patients not numbers. Lancet Diabetes Endocrinol 2019; 7:473-483. [PMID: 30797750 DOI: 10.1016/s2213-8587(18)30371-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 12/05/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022]
Abstract
Although assigning a diagnosis of thyroid dysfunction appears quite simple, this is often not the case. Issues that make it unclear whether thyroid function is normal include transient changes in thyroid parameters, inter-individual and intra-individual differences in thyroid parameters, age-related differences, and ethnic variations. In addition, a statistically calculated distribution of thyroid analytes does not necessarily coincide with intervals or cutoffs that have predictive value for beneficial or adverse health outcomes. Based on current clincial trial data, it is unclear which individuals with mild thyroid-stimulating hormone elevations will benefit from levothyroxine treatment. For example, only a small number of patients with thyroid-stimulating hormone values of more than 10 mIU/L have been studied in a randomised manner. Even if therapy is initiated for abnormal thyroid function, not all treated individuals are maintained at the desired treatment target, and therefore might still be at risk. The consequence of this is that each patient's thyroid function needs to be assessed on an individual basis with the entire clinical picture in mind. Monitoring also needs to be vigilant, and the targets for treatment reassessed continually.
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Affiliation(s)
| | - Salman Razvi
- Department of Endocrinology, University of Newcastle, Newcastle, UK
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Berberich J, Dietrich JW, Hoermann R, Müller MA. Mathematical Modeling of the Pituitary-Thyroid Feedback Loop: Role of a TSH-T 3-Shunt and Sensitivity Analysis. Front Endocrinol (Lausanne) 2018; 9:91. [PMID: 29619006 PMCID: PMC5871688 DOI: 10.3389/fendo.2018.00091] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 02/26/2018] [Indexed: 01/08/2023] Open
Abstract
Despite significant progress in assay technology, diagnosis of functional thyroid disorders may still be a challenge, as illustrated by the vague upper limit of the reference range for serum thyrotropin (TSH). Diagnostical problems also apply to subjects affected by syndrome T, i.e., those 10% of hypothyroid patients who continue to suffer from poor quality of life despite normal TSH concentrations under substitution therapy with levothyroxine (L-T4). In this paper, we extend a mathematical model of the pituitary-thyroid feedback loop in order to improve the understanding of thyroid hormone homeostasis. In particular, we incorporate a TSH-T3-shunt inside the thyroid, whose existence has recently been demonstrated in several clinical studies. The resulting extended model shows good accordance with various clinical observations, such as a circadian rhythm in free peripheral triiodothyronine (FT3). Furthermore, we perform a sensitivity analysis of the derived model, revealing the dependence of TSH and hormone concentrations on different system parameters. The results have implications for clinical interpretation of thyroid tests, e.g., in the differential diagnosis of subclinical hypothyroidism.
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Affiliation(s)
- Julian Berberich
- Institute for Systems Theory and Automatic Control, University of Stuttgart, Stuttgart, Germany
| | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Witten/Herdecke University, Bochum, Germany
| | - Rudolf Hoermann
- Private Consultancy Research & Development, Yandina, QLD, Australia
| | - Matthias A. Müller
- Institute for Systems Theory and Automatic Control, University of Stuttgart, Stuttgart, Germany
- *Correspondence: Matthias A. Müller,
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Dietrich JW, Midgley JEM, Hoermann R. Editorial: "Homeostasis and Allostasis of Thyroid Function". Front Endocrinol (Lausanne) 2018; 9:287. [PMID: 29922229 PMCID: PMC5996081 DOI: 10.3389/fendo.2018.00287] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/15/2018] [Indexed: 12/14/2022] Open
Affiliation(s)
- Johannes W. Dietrich
- Medical Department 1, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, North Rhine-Westphalia, Germany
- Ruhr Centre of Rare Diseases (CeSER), Ruhr University of Bochum, Bochum, North Rhine-Westphalia, Germany
- Ruhr Centre of Rare Diseases (CeSER), Witten/Herdecke University, Bochum, North Rhine-Westphalia, Germany
- *Correspondence: Johannes W. Dietrich,
| | | | - Rudolf Hoermann
- Private Consultancy, Research and Development, Yandina, QLD, Australia
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Hoermann R, Midgley JEM, Larisch R, Dietrich JWC. Advances in applied homeostatic modelling of the relationship between thyrotropin and free thyroxine. PLoS One 2017; 12:e0187232. [PMID: 29155897 PMCID: PMC5695809 DOI: 10.1371/journal.pone.0187232] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/16/2017] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION The relationship between pituitary TSH and thyroid hormones is central to our understanding of thyroid physiology and thyroid function testing. Here, we generated distribution patterns by using validated tools of thyroid modelling. METHODS We simulated patterns of individual set points under various conditions, based on a homeostatic model of thyroid feedback control. These were compared with observed data points derived from clinical trials. RESULTS A random mix of individual set points was reconstructed by simulative modelling with defined structural parameters. The pattern displayed by the cluster of hypothetical points resembled that observed in a natural control group. Moderate variation of the TSH-FT4 gradient over the functional range introduced further flexibility, implementing a scenario of adaptive set points. Such a scenario may be a realistic possibility for instance in treatment where relationships and equilibria between thyroid parameters are altered by various influences such as LT4 dose and conversion efficiency. CONCLUSIONS We validated a physiologically based homeostatic model that permits simulative reconstruction of individual set points. This produced a pattern resembling the observed data under various conditions. Applied modelling, although still experimental at this stage, shows a potential to aid our physiological understanding of the interplay between TSH and thyroid hormones. It should eventually benefit personalised clinical decision making.
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Affiliation(s)
- Rudolf Hoermann
- Department for Nuclear Medicine, Klinikum Lüdenscheid, Paulmannshöherstr, Lüdenscheid, Germany
| | | | - Rolf Larisch
- Department for Nuclear Medicine, Klinikum Lüdenscheid, Paulmannshöherstr, Lüdenscheid, Germany
| | - Johannes Wolfgang Christian Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum, Alexandrinenstr. 5, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Witten/Herdecke University, Alexandrinenstr. 5, Bochum, Germany
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Hoermann R, Midgley JEM, Dietrich JW, Larisch R. Dual control of pituitary thyroid stimulating hormone secretion by thyroxine and triiodothyronine in athyreotic patients. Ther Adv Endocrinol Metab 2017; 8:83-95. [PMID: 28794850 PMCID: PMC5524252 DOI: 10.1177/2042018817716401] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/29/2017] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Patient responses to levothyroxine (LT4) monotherapy vary considerably. We sought to differentiate contributions of FT4 and FT3 in controlling pituitary thyroid stimulating hormone (TSH) secretion. METHODS We retrospectively assessed the relationships between TSH and thyroid hormones in 319 patients with thyroid carcinoma through 2914 visits on various LT4 doses during follow-up for 5.5 years (median, IQR 4.2, 6.9). We also associated patient complaints with the relationships. RESULTS Under varying dose requirements (median 1.84 µg/kg, IQR 1.62, 2.11), patients reached TSH targets below 0.4, 0.1 or 0.01 mIU/l at 73%, 54% and 27% of visits. While intercept, slope and fit of linearity of the relationships between lnTSH and FT4/FT3 varied between individuals, gender, age, LT4 dose and deiodinase activity influenced the relationships in the cohort (all p < 0.001). Deiodinase activity impaired by LT4 dose significantly affected the lnTSH-FT4 relationship. Dose increase and reduced conversion efficiency displaced FT3-TSH equilibria. In LT4-treated patients, FT4 and FT3 contributed on average 52% versus 38%, and by interaction 10% towards TSH suppression. Symptomatic presentations (11%) accompanied reduced FT3 concentrations (-0.23 pmol/l, p = 0.001) adjusted for gender, age and BMI, their relationships being shifted towards higher TSH values at comparable FT3/FT4 levels. CONCLUSIONS Variation in deiodinase activity and resulting FT3 levels shape the TSH-FT4 relationship in LT4-treated athyreotic patients, suggesting cascade control of pituitary TSH production by the two hormones. Consequently, measurement of FT3 and calculation of conversion efficiency may identify patients with impaired biochemistry and a resulting lack of symptomatic control.
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Affiliation(s)
- Rudolf Hoermann
- Department of Nuclear Medicine, Klinikum Lüdenscheid, Paulmannshoeher Str 14, D-58515 Luedenscheid, Germany
| | | | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
| | - Rolf Larisch
- Department of Nuclear Medicine, Klinikum Lüdenscheid, Lüdenscheid, Germany
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Chatzitomaris A, Hoermann R, Midgley JE, Hering S, Urban A, Dietrich B, Abood A, Klein HH, Dietrich JW. Thyroid Allostasis-Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming. Front Endocrinol (Lausanne) 2017; 8:163. [PMID: 28775711 PMCID: PMC5517413 DOI: 10.3389/fendo.2017.00163] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 06/27/2017] [Indexed: 12/21/2022] Open
Abstract
The hypothalamus-pituitary-thyroid feedback control is a dynamic, adaptive system. In situations of illness and deprivation of energy representing type 1 allostasis, the stress response operates to alter both its set point and peripheral transfer parameters. In contrast, type 2 allostatic load, typically effective in psychosocial stress, pregnancy, metabolic syndrome, and adaptation to cold, produces a nearly opposite phenotype of predictive plasticity. The non-thyroidal illness syndrome (NTIS) or thyroid allostasis in critical illness, tumors, uremia, and starvation (TACITUS), commonly observed in hospitalized patients, displays a historically well-studied pattern of allostatic thyroid response. This is characterized by decreased total and free thyroid hormone concentrations and varying levels of thyroid-stimulating hormone (TSH) ranging from decreased (in severe cases) to normal or even elevated (mainly in the recovery phase) TSH concentrations. An acute versus chronic stage (wasting syndrome) of TACITUS can be discerned. The two types differ in molecular mechanisms and prognosis. The acute adaptation of thyroid hormone metabolism to critical illness may prove beneficial to the organism, whereas the far more complex molecular alterations associated with chronic illness frequently lead to allostatic overload. The latter is associated with poor outcome, independently of the underlying disease. Adaptive responses of thyroid homeostasis extend to alterations in thyroid hormone concentrations during fetal life, periods of weight gain or loss, thermoregulation, physical exercise, and psychiatric diseases. The various forms of thyroid allostasis pose serious problems in differential diagnosis of thyroid disease. This review article provides an overview of physiological mechanisms as well as major diagnostic and therapeutic implications of thyroid allostasis under a variety of developmental and straining conditions.
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Affiliation(s)
- Apostolos Chatzitomaris
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- *Correspondence: Apostolos Chatzitomaris,
| | - Rudolf Hoermann
- Private Consultancy, Research and Development, Yandina, QLD, Australia
| | | | - Steffen Hering
- Department for Internal Medicine, Cardiology, Endocrinology, Diabetes and Medical Intensive Care Medicine, Krankenhaus Bietigheim-Vaihingen, Bietigheim-Bissingen, Germany
| | - Aline Urban
- Department for Anesthesiology, Intensive Care and Palliative Medicine, Eastern Allgäu-Kaufbeuren Hospitals, Kaufbeuren, Germany
| | | | - Assjana Abood
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
| | - Harald H. Klein
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
| | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
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Hoermann R, Midgley JEM, Larisch R, Dietrich JW. Relational Stability in the Expression of Normality, Variation, and Control of Thyroid Function. Front Endocrinol (Lausanne) 2016; 7:142. [PMID: 27872610 PMCID: PMC5098235 DOI: 10.3389/fendo.2016.00142] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 10/21/2016] [Indexed: 12/31/2022] Open
Abstract
Thyroid hormone concentrations only become sufficient to maintain a euthyroid state through appropriate stimulation by pituitary thyroid-stimulating hormone (TSH). In such a dynamic system under constant high pressure, guarding against overstimulation becomes vital. Therefore, several defensive mechanisms protect against accidental overstimulation, such as plasma protein binding, conversion of T4 into the more active T3, active transmembrane transport, counter-regulatory activities of reverse T3 and thyronamines, and negative hypothalamic-pituitary-thyroid feedback control of TSH. TSH has gained a dominant but misguided role in interpreting thyroid function testing in assuming that its exceptional sensitivity thereby translates into superior diagnostic performance. However, TSH-dependent thyroid disease classification is heavily influenced by statistical analytic techniques such as uni- or multivariate-defined normality. This demands a separation of its conjoint roles as a sensitive screening test and accurate diagnostic tool. Homeostatic equilibria (set points) in healthy subjects are less variable and do not follow a pattern of random variation, rather indicating signs of early and progressive homeostatic control across the euthyroid range. In the event of imminent thyroid failure with a reduced FT4 output per unit TSH, conversion efficiency increases in order to maintain FT3 stability. In such situations, T3 stability takes priority over set point maintenance. This suggests a concept of relational stability. These findings have important implications for both TSH reference limits and treatment targets for patients on levothyroxine. The use of archival markers is proposed to facilitate the homeostatic interpretation of all parameters.
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Affiliation(s)
- Rudolf Hoermann
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
| | | | - Rolf Larisch
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
| | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Witten/Herdecke University, Bochum, Germany
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Hoermann R, Midgley JE, Larisch R, Dietrich JW. Relational Stability of Thyroid Hormones in Euthyroid Subjects and Patients with Autoimmune Thyroid Disease. Eur Thyroid J 2016; 5:171-179. [PMID: 27843807 PMCID: PMC5091265 DOI: 10.1159/000447967] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 06/21/2016] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND/AIM Operating far from its equilibrium resting point, the thyroid gland requires stimulation via feedback-controlled pituitary thyrotropin (TSH) secretion to maintain adequate hormone supply. We explored and defined variations in the expression of control mechanisms and physiological responses across the euthyroid reference range. METHODS We analyzed the relational equilibria between thyroid parameters defining thyroid production and thyroid conversion in a group of 271 thyroid-healthy subjects and 86 untreated patients with thyroid autoimmune disease. RESULTS In the euthyroid controls, the FT3-FT4 (free triiodothyronine-free thyroxine) ratio was strongly associated with the FT4-TSH ratio (tau = -0.22, p < 0.001, even after correcting for spurious correlation), linking T4 to T3 conversion with TSH-standardized T4 production. Using a homeostatic model, we estimated both global deiodinase activity and maximum thyroid capacity. Both parameters were nonlinearly and inversely associated, trending in opposite directions across the euthyroid reference range. Within the panel of controls, the subgroup with a relatively lower thyroid capacity (<2.5 pmol/s) displayed lower FT4 levels, but maintained FT3 at the same concentrations as patients with higher functional and anatomical capacity. The relationships were preserved when extended to the subclinical range in the diseased sample. CONCLUSION The euthyroid panel does not follow a homogeneous pattern to produce random variation among thyroid hormones and TSH, but forms a heterogeneous group that progressively displays distinctly different levels of homeostatic control across the euthyroid range. This suggests a concept of relational stability with implications for definition of euthyroidism and disease classification.
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Affiliation(s)
- Rudolf Hoermann
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
- *Prof. Dr. Rudolf Hoermann, Department of Nuclear Medicine, Klinikum Luedenscheid, Paulmannshoeher Strasse 14, DE-58515 Luedenscheid (Germany), E-Mail
| | | | - Rolf Larisch
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
| | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
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Dietrich JW, Landgrafe-Mende G, Wiora E, Chatzitomaris A, Klein HH, Midgley JEM, Hoermann R. Calculated Parameters of Thyroid Homeostasis: Emerging Tools for Differential Diagnosis and Clinical Research. Front Endocrinol (Lausanne) 2016; 7:57. [PMID: 27375554 PMCID: PMC4899439 DOI: 10.3389/fendo.2016.00057] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/23/2016] [Indexed: 11/30/2022] Open
Abstract
Although technical problems of thyroid testing have largely been resolved by modern assay technology, biological variation remains a challenge. This applies to subclinical thyroid disease, non-thyroidal illness syndrome, and those 10% of hypothyroid patients, who report impaired quality of life, despite normal thyrotropin (TSH) concentrations under levothyroxine (L-T4) replacement. Among multiple explanations for this condition, inadequate treatment dosage and monotherapy with L-T4 in subjects with impaired deiodination have received major attention. Translation to clinical practice is difficult, however, since univariate reference ranges for TSH and thyroid hormones fail to deliver robust decision algorithms for therapeutic interventions in patients with more subtle thyroid dysfunctions. Advances in mathematical and simulative modeling of pituitary-thyroid feedback control have improved our understanding of physiological mechanisms governing the homeostatic behavior. From multiple cybernetic models developed since 1956, four examples have also been translated to applications in medical decision-making and clinical trials. Structure parameters representing fundamental properties of the processing structure include the calculated secretory capacity of the thyroid gland (SPINA-GT), sum activity of peripheral deiodinases (SPINA-GD) and Jostel's TSH index for assessment of thyrotropic pituitary function, supplemented by a recently published algorithm for reconstructing the personal set point of thyroid homeostasis. In addition, a family of integrated models (University of California-Los Angeles platform) provides advanced methods for bioequivalence studies. This perspective article delivers an overview of current clinical research on the basis of mathematical thyroid models. In addition to a summary of large clinical trials, it provides previously unpublished results of validation studies based on simulation and clinical samples.
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Affiliation(s)
- Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Witten/Herdecke University, Bochum, Germany
- *Correspondence: Johannes W. Dietrich,
| | - Gabi Landgrafe-Mende
- Zentrum für Unfallchirurgie, Orthopädie und Wirbelsäulenchirurgie, HELIOS Klinikum Schwelm, Schwelm, Germany
| | - Evelin Wiora
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
| | - Apostolos Chatzitomaris
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
| | - Harald H. Klein
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Witten/Herdecke University, Bochum, Germany
| | | | - Rudolf Hoermann
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
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