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Abstract
Thyroid disease, increasingly common among the general population, is also rising among the elderly, which, given that the global population is aging, constitutes a serious public health issue that needs to be urgently addressed. The most common thyroid disease in younger and older individuals alike is hypothyroidism, including subclinical (SCH) and overt disease. Since TSH tends to increase with age due to intrinsic changes of thyroid metabolism and the gradual resetting of the hypothalamic-pituitary-thyroid axis, the diagnosis of "true" hypothyroidism is challenging, another difficulty being distinguishing disease-specific from aging-associated clinical symptoms. Hypothyroidism in the elderly may cause or exacerbate macrocytic anemia, hypercholesterolemia and kidney dysfunction, therefore careful clinical and biochemical control is necessary. Meanwhile, as an increase of TSH in the old and very old has been associated with longevity, a resetting of the TSH normal range according to age is strongly required before any diagnosis is made and treatment is implemented. Levothyroxine, which remains the treatment of choice, should be initiated in the old at TSH>10 mIU/l, starting with 25 μg/daily followed by cautious upward titration. Recent data (the TRUST study) revealed that treatment of SCH in the elderly does not improve hypothyroid symptoms and the tiredness score when compared with a placebo group. Hyperthyroidism is associated with increased mortality in the aged, this dependent upon type and adequacy of treatment. Treatment should be seriously considered in older patients who have endogenous subclinical hyperthyroidism with a TSH between 0.1 and 0.4 mIU/L, with regular monitoring being strongly advised.
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Affiliation(s)
- Leonidas H Duntas
- Unit of Endocrinology, Diabetes and Metabolism, Evgenideion Hospital, University of Athens , Athens, Greece
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Duarte GC, Araujo LMQ, Magalhães F, Almada CM, Cendoroglo MS. Ultrasonographic assessment of thyroid volume in oldest-old individuals. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2016; 61:269-275. [PMID: 27901180 PMCID: PMC10118803 DOI: 10.1590/2359-3997000000223] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 08/10/2016] [Indexed: 11/22/2022]
Abstract
Objective The aim of this study was to describe the relationship between thyroid volume and age, gender, anthropometric characteristics, and echogenicity in oldest-old subjects in an iodine-sufficient area. Subjects and methods The study included 81 independent elderly individuals aged ≥ 80 years (65 [80.2%] women). We determined these individuals' anthropometric characteristics, body mass index (BMI), and lean body mass, as well as thyroid volume and echogenicity by ultrasonography. Results We observed that octogenarians and nonagenarians had different profiles of thyroid echogenicity. The volume of the thyroid was smaller in nonagenarians than octogenarians (p = 0.012, r = 0.176), and subjects aged 80-89 years had more often hypoechoic glands than those aged ≥ 90 years (p = 0.01 versus 0.602). Conclusion The identification of ultrasonographic differences in oldest-old individuals will contribute to establishing preclinical markers, such as echogenicity, to identify individuals at risk of developing autoimmune thyroid disease. Future prospective studies should identify if 80-89-year-old individuals with hypoechoic glands progress to hypothyroidism, and if the absence of changes in echogenicity (i.e. a normal thyroid parenchyma) would have a positive impact on longevity among nonagenarians.
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Affiliation(s)
- Glaucia Cruzes Duarte
- Disciplina de Geriatria e Gerontologia, Universidade Federal de São Paulo (Unifesp), São Paulo, SP, Brasil
| | - Lara Miguel Quirino Araujo
- Disciplina de Geriatria e Gerontologia, Universidade Federal de São Paulo (Unifesp), São Paulo, SP, Brasil
| | - Felix Magalhães
- Disciplina de Geriatria e Gerontologia, Universidade Federal de São Paulo (Unifesp), São Paulo, SP, Brasil
| | - Clineu Mello Almada
- Disciplina de Geriatria e Gerontologia, Universidade Federal de São Paulo (Unifesp), São Paulo, SP, Brasil
| | - Maysa Seabra Cendoroglo
- Disciplina de Geriatria e Gerontologia, Universidade Federal de São Paulo (Unifesp), São Paulo, SP, Brasil
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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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Duarte GC, Cendoroglo MS, Araújo LMQ, Almada CDM. Association between increased serum thyrotropin concentration and the oldest old: what do we know? EINSTEIN-SAO PAULO 2015; 13:117-21. [PMID: 25807244 PMCID: PMC4946819 DOI: 10.1590/s1679-45082015rw2874] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 06/28/2014] [Indexed: 01/07/2023] Open
Abstract
To assess studies that evaluate the relation between serum thyrotropin concentration, very old subjects, and their events. We searched the PubMed, SciELO, and LILACS databases for articles published between 2004 and 2012. Our search was restricted to studies involving humans aged 65 years or older, and written in English, Spanish, or Portuguese. Studies that evaluated the association between elevated serum thyrotropin concentration among elderly subjects with subclinical hypothyroidism were chosen since at least in part they included a subpopulation of individuals aged 80 years and above. Thirteen studies were selected. No significant increase in risk of cardiovascular events, coronary heart disease, or total mortality was observed. Elevated thyrotropin concentration was associated with longevity. More randomized controlled trials are required to better define the potential benefits of elevated thyrotropin concentration in this oldest old population, hormone replacement, and longevity.
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Fontes R, Coeli CR, Aguiar F, Vaisman M. Reference interval of thyroid stimulating hormone and free thyroxine in a reference population over 60 years old and in very old subjects (over 80 years): comparison to young subjects. Thyroid Res 2013; 6:13. [PMID: 24365659 PMCID: PMC3877984 DOI: 10.1186/1756-6614-6-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 12/18/2013] [Indexed: 12/16/2022] Open
Abstract
Background Studies based on laboratory data about thyroid stimulating hormone (TSH) and free thyroxine (FT4) reference interval (RI) show conflicting results regarding the importance of using specific values by age groups with advancing age. Retrospective laboratory data or non-specific criteria in the selection of subjects to be studied may be factors leading to no clear conclusions. The aim of this study is to test the hypothesis that TSH and FT4 have specific RI for subjects over 60 to 80 years. Methods We evaluated prospectively 1200 subjects of both sexes stratified by age groups, initially submitted to a questionnaire to do the first selection to exclude those with factors that could interfere in TSH or FT4 levels. Then, we excluded those subjects with goiter or other abnormalities on physical examination, positive thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TGAb), and other laboratory abnormalities. Results TSH increased with age in the whole group. There was no statistical difference in the analysis of these independent subgroups: 20–49 versus 50–59 years old (p > 0.05), and 60–69 versus 70–79 years old (p > 0.05). Consequently, we achieved different TSH RI for the three major age groups, 20 to 59 years old: 0.4 - 4.3 mU/L, 60 to 79 years old: 0.4 - 5.8 mU/L and 80 years or more: 0.4 - 6.7 mU/L. Conversely, FT4 progressively decreases = significantly with age, but the independent comparison test between the sub-groups showed that after age 60 the same RI was obtained (0.7 - 1.7 ng/dL) although the minimum value was smaller than that defined by manufacturer. In the comparison between TSH data obtained by this study and those defined by the manufacturer (without segmentation by age) 6.5% of subjects between 60 and 79 years and 12.5% with 80 years or more would have a misdiagnosis of elevated TSH. Conclusions TSH normal reference range increases with age, justifying the use of different RI in subjects 60 years old and over, while FT4 decreases with age. Using specific-age RI, a significant percentage of elderly will not be misdiagnosed as having subclinical hipothyroidism.
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Affiliation(s)
- Rosita Fontes
- Hospital Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rua Prof, Rodolpho Paulo Rocco 255, Cidade Universitária, CEP 21941-913, Rio de Janeiro-RJ, Brazil.
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Retornaz F, Castinetti F, Molines C, Oliver C. La thyroïde de la personne âgée (partie 2). Rev Med Interne 2013; 34:694-9. [DOI: 10.1016/j.revmed.2012.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/30/2012] [Accepted: 11/26/2012] [Indexed: 11/24/2022]
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Gentilini D, Mari D, Castaldi D, Remondini D, Ogliari G, Ostan R, Bucci L, Sirchia SM, Tabano S, Cavagnini F, Monti D, Franceschi C, Di Blasio AM, Vitale G. Role of epigenetics in human aging and longevity: genome-wide DNA methylation profile in centenarians and centenarians' offspring. AGE (DORDRECHT, NETHERLANDS) 2013; 35:1961-73. [PMID: 22923132 PMCID: PMC3776126 DOI: 10.1007/s11357-012-9463-1] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 07/24/2012] [Indexed: 05/13/2023]
Abstract
The role of epigenetics in the modulation of longevity has not been studied in humans. To this aim, (1) we evaluated the DNA methylation from peripheral leukocytes of 21 female centenarians, their 21 female offspring, 21 offspring of both non-long-lived parents, and 21 young women through ELISA assay, pyrosequencing analysis of Alu sequences, and quantification of methylation in CpG repeats outside CpG islands; (2) we compared the DNA methylation profiles of these populations through Infinium array for genome-wide CpG methylation analysis. We observed an age-related decrease in global DNA methylation and a delay of this process in centenarians' offspring. Interestingly, literature data suggest a link between the loss of DNA methylation observed during aging and the development of age-associated diseases. Genome-wide methylation analysis evidenced DNA methylation profiles specific for aging and longevity: (1) aging-associated DNA hypermethylation occurs predominantly in genes involved in the development of anatomical structures, organs, and multicellular organisms and in the regulation of transcription; (2) genes involved in nucleotide biosynthesis, metabolism, and control of signal transmission are differently methylated between centenarians' offspring and offspring of both non-long-lived parents, hypothesizing a role for these genes in human longevity. Our results suggest that a better preservation of DNA methylation status, a slower cell growing/metabolism, and a better control in signal transmission through epigenetic mechanisms may be involved in the process of human longevity. These data fit well with the observations related to the beneficial effects of mild hypothyroidism and insulin-like growth factor I system impairment on the modulation of human lifespan.
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Affiliation(s)
- Davide Gentilini
- />Centro di Ricerche e Tecnologie Biomediche, Istituto Auxologico Italiano IRCCS, Via Zucchi 18, Cusano Milanino, 20095 Milan, Italy
| | - Daniela Mari
- />Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
- />Geriatric Unit, IRCCS Ca’ Granda Foundation Maggiore Policlinico Hospital, Milan, Italy
| | - Davide Castaldi
- />Centro di Ricerche e Tecnologie Biomediche, Istituto Auxologico Italiano IRCCS, Via Zucchi 18, Cusano Milanino, 20095 Milan, Italy
- />Dipartimento di Informatica, Sistemistica e Comunicazione, Universita’ degli Studi di Milano-Bicocca, Milan, Italy
| | | | - Giulia Ogliari
- />Geriatric Unit, IRCCS Ca’ Granda Foundation Maggiore Policlinico Hospital, Milan, Italy
| | - Rita Ostan
- />Department of Experimental Pathology, University of Bologna, Bologna, Italy
- />CIG-Interdepartmental Center “L. Galvani”, University of Bologna, Bologna, Italy
| | - Laura Bucci
- />Department of Experimental Pathology, University of Bologna, Bologna, Italy
- />CIG-Interdepartmental Center “L. Galvani”, University of Bologna, Bologna, Italy
| | - Silvia M. Sirchia
- />Medical Genetics Unit, Dipartimento di Medicina, Chirurgia e Odontoiatria, Università degli Studi di Milano, Milan, Italy
| | - Silvia Tabano
- />Medical Genetics Unit, Dipartimento di Medicina, Chirurgia e Odontoiatria, Università degli Studi di Milano, Milan, Italy
| | - Francesco Cavagnini
- />Centro di Ricerche e Tecnologie Biomediche, Istituto Auxologico Italiano IRCCS, Via Zucchi 18, Cusano Milanino, 20095 Milan, Italy
| | - Daniela Monti
- />Department of Experimental Pathology and Oncology, University of Florence, Florence, Italy
| | - Claudio Franceschi
- />Department of Experimental Pathology, University of Bologna, Bologna, Italy
- />CIG-Interdepartmental Center “L. Galvani”, University of Bologna, Bologna, Italy
| | - Anna Maria Di Blasio
- />Centro di Ricerche e Tecnologie Biomediche, Istituto Auxologico Italiano IRCCS, Via Zucchi 18, Cusano Milanino, 20095 Milan, Italy
| | - Giovanni Vitale
- />Centro di Ricerche e Tecnologie Biomediche, Istituto Auxologico Italiano IRCCS, Via Zucchi 18, Cusano Milanino, 20095 Milan, Italy
- />Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
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Bowers J, Terrien J, Clerget-Froidevaux MS, Gothié JD, Rozing MP, Westendorp RGJ, van Heemst D, Demeneix BA. Thyroid hormone signaling and homeostasis during aging. Endocr Rev 2013; 34:556-89. [PMID: 23696256 DOI: 10.1210/er.2012-1056] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Studies in humans and in animal models show negative correlations between thyroid hormone (TH) levels and longevity. TH signaling is implicated in maintaining and integrating metabolic homeostasis at multiple levels, notably centrally in the hypothalamus but also in peripheral tissues. The question is thus raised of how TH signaling is modulated during aging in different tissues. Classically, TH actions on mitochondria and heat production are obvious candidates to link negative effects of TH to aging. Mitochondrial effects of excess TH include reactive oxygen species and DNA damage, 2 factors often considered as aging accelerators. Inversely, caloric restriction, which can retard aging from nematodes to primates, causes a rapid reduction of circulating TH, reducing metabolism in birds and mammals. However, many other factors could link TH to aging, and it is these potentially subtler and less explored areas that are highlighted here. For example, effects of TH on membrane composition, inflammatory responses, stem cell renewal and synchronization of physiological responses to light could each contribute to TH regulation of maintenance of homeostasis during aging. We propose the hypothesis that constraints on TH signaling at certain life stages, notably during maturity, are advantageous for optimal aging.
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Affiliation(s)
- J Bowers
- Muséum national d'Histoire Naturelle, Laboratoire de Physiologie Générale et Comparée, Unité Mixte de Recherche, Centre National de la Recherche Scientifique 7221, 75231 Paris cedex 5, France
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Wijsman LW, de Craen AJM, Trompet S, Gussekloo J, Stott DJ, Rodondi N, Welsh P, Jukema JW, Westendorp RGJ, Mooijaart SP. Subclinical thyroid dysfunction and cognitive decline in old age. PLoS One 2013; 8:e59199. [PMID: 23554996 PMCID: PMC3595244 DOI: 10.1371/journal.pone.0059199] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 02/12/2013] [Indexed: 01/07/2023] Open
Abstract
Background Subclinical thyroid dysfunction has been implicated as a risk factor for cognitive decline in old age, but results are inconsistent. We investigated the association between subclinical thyroid dysfunction and cognitive decline in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). Methods Prospective longitudinal study of men and women aged 70–82 years with pre-existing vascular disease or more than one risk factor to develop this condition (N = 5,154). Participants taking antithyroid medications, thyroid hormone supplementation and/or amiodarone were excluded. Thyroid function was measured at baseline: subclinical hyper- and hypothyroidism were defined as thyroid stimulating hormones (TSH) <0.45 mU/L or >4.50 mU/L respectively, with normal levels of free thyroxine (FT4). Cognitive performance was tested at baseline and at four subsequent time points during a mean follow-up of 3 years, using five neuropsychological performance tests. Results Subclinical hyperthyroidism and hypothyroidism were found in 65 and 161 participants, respectively. We found no consistent association of subclinical hyper- or hypothyroidism with altered cognitive performance compared to euthyroid participants on the individual cognitive tests. Similarly, there was no association with rate of cognitive decline during follow-up. Conclusion We found no consistent evidence that subclinical hyper- or hypothyroidism contribute to cognitive impairment or decline in old age. Although our data are not in support of treatment of subclinical thyroid dysfunction to prevent cognitive dysfunction in later life, only large randomized controlled trials can provide definitive evidence.
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Affiliation(s)
- Liselotte W. Wijsman
- Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Anton J. M. de Craen
- Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Stella Trompet
- Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jacobijn Gussekloo
- Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, The Netherlands
| | - David J. Stott
- Academic Section of Geriatric Medicine, Faculty of Medicine, University of Glasgow, Glasgow, Scotland
| | - Nicolas Rodondi
- Department of General Internal Medicine, Inselhospital, University of Bern, Bern, Switzerland
| | - Paul Welsh
- British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, Scotland
| | - J. Wouter Jukema
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Rudi G. J. Westendorp
- Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Simon P. Mooijaart
- Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands
- Institute for Evidence-Based Medicine in Old Age | IEMO, Leiden, The Netherlands
- * E-mail:
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De Alfieri W, Nisticò F, Borgogni T, Riello F, Cellai F, Mori C, Nante N, Di Bari M. Thyroid hormones as predictors of short- and long-term mortality in very old hospitalized patients. J Gerontol A Biol Sci Med Sci 2013; 68:1122-8. [PMID: 23459207 DOI: 10.1093/gerona/glt012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Although extensively investigated, the prognostic role of thyroid hormone abnormalities in older participants remains uncertain. We investigated the relationship between thyroid hormones and mortality during hospitalization and in a prolonged follow-up in frail older patients. METHODS A nonconcurrent cohort study was conducted by enrolling 450 participants hospitalized for an acute disease, who were classified into four groups (euthyroidism, hypothyroidism, hyperthyroidism, and low triiodothyronine [T3] syndrome), according to clinical and laboratory data. Multidimensional geriatric assessment variables were considered in order to identify short- and long-term predictors of death. RESULTS Participants were very old (mean age: 84 years) and frail, as indicated by severely impaired functional status, extensive comorbidity, high prevalence of dementia, and hospital mortality (8%). Prevalence of any thyroid dysfunction was 40.7%; 32% of participants had low T3 syndrome, which was associated with an excess hospital mortality risk (odds ratio: 2.7, 95% confidence interval [CI]: 1.1-6.5; p = .025), adjusted for demographic, clinical, functional, and laboratory data. Conversely, long-term mortality was unrelated to low T3 syndrome. In euthyroid participants, increasing levels of free thyroxine (FT4) were associated with a slightly greater mortality (hazard ratio, CI: 2.12, 0.99-4.54; p = .053) in adjusted Cox regression models. CONCLUSIONS This observational study on a cohort of very old, frail hospitalized patients gives support to the independent prognostic short-term, but not long-term, role of low T3 syndrome. Moreover, in older euthyroid participants, increasing levels of FT4 are a weak marker of poorer long-term survival. Thyroid hormones may help monitor changes in general health status and predict short- and long-term clinical outcomes in very old, frail patients.
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Affiliation(s)
- Walter De Alfieri
- Unit of Geriatrics, Casteldelpiano Hospital, Azienda USL 9 Grosseto, Italy
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TSH Measurement and Its Implications for Personalised Clinical Decision-Making. J Thyroid Res 2012; 2012:438037. [PMID: 23304636 PMCID: PMC3529417 DOI: 10.1155/2012/438037] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 11/15/2012] [Indexed: 02/08/2023] Open
Abstract
Advances in assay technology have promoted thyrotropin (TSH) measurements from participation in a multi-analyte assessment of thyroid function to a statistically defined screening parameter in its own right. While this approach has been successful in many ways, it has some grave limitations. This includes the basic question of what constitutes an agreed reference range and the fact that the population-based reference range by far exceeds the variation of the intraindividual set point. Both problems result in a potential misdiagnosis of normal and pathological thyroid function in a substantial proportion of patients. From a physiological perspective, TSH plays an integrated role in thyroid homeostasis. Few attempts have been made to adopt physiological insights into thyroid homeostasis for medical decision-making. Some emerging novel findings question the widely assumed log-linear TSH-FT4 relationship over the entire thyroid function spectrum. This data favours more complex hierarchically structured models. With a better understanding of its role in thyroid homeostasis in thyroid health and disease, TSH can be revisited in the context of thyroid regulation. This, in turn, could help overcome some of the limitations arising from its isolated statistical use and offer new prospects towards a more personalised interpretation of thyroid test results.
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Gentilini D, Castaldi D, Mari D, Monti D, Franceschi C, Di Blasio AM, Vitale G. Age-dependent skewing of X chromosome inactivation appears delayed in centenarians' offspring. Is there a role for allelic imbalance in healthy aging and longevity? Aging Cell 2012; 11:277-83. [PMID: 22292741 DOI: 10.1111/j.1474-9726.2012.00790.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Recently, it has been proposed that age-related X chromosome inactivation (XCI) skewing can clinically result in late-onset X-linked disorders. This observation leads to hypothesize that age-related skewed XCI might also influence lifespan in women. To investigate this issue, we employed a new experimental model of longevity and healthy aging including 55 female centenarians, 40 of their offspring, 33 age-matched offspring of both non-long-lived parents and 41 young women. Peripheral blood DNA from 169 females was screened for heterozygosity at the HUMARA locus. We confirmed that skewing of XCI is an age-dependent phenomenon. However, skewed XCI was significantly less severe and frequent in centenarians' offspring [degree of skewing (DS) = 0.16 ± 0.02] compared to age-matched offspring of both non-long-lived parents (DS = 0.24 ± 0.02) (P < 0.05). A second goal was to assess whether changes in XCI pattern could be a consequence of loss of methylation on X chromosome. Using a methylation array evaluating 1085 CpG sites across X chromosome and eleven CpG sites located at HUMARA locus, no differences in methylation levels and profiles emerged between all groups analysed, thus suggesting that age-associated epigenetic changes could not influence HUMARA results. In conclusion, the results presented herein highlight for the first time an interesting link between skewing of XCI and healthy aging and longevity. We speculate that the allelic imbalance produced by XCI skewing may compromise the cooperative and compensatory organization occurring between the two cell populations that make up the female mosaic.
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Triiodothyronine stimulates cystatin C production in bone cells. Biochem Biophys Res Commun 2012; 419:425-30. [DOI: 10.1016/j.bbrc.2012.02.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 02/07/2012] [Indexed: 11/21/2022]
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