Mahsa Dolatshahi1,2, Arash Salehipour2,3, Amene Saghazadeh4,5, Hossein Sanjeari Moghaddam5, Vajiheh Aghamollaii5,6, Akbar Fotouhi7, Abbas Tafakhori8,9. 1. Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, 510 South Kingshighway Boulevard, Campus Box 8131, St. Louis, MO, 63110, USA. 2. NeuroImaging Network (NIN), Universal Scientific Education and Research Network (USERN), Tehran, Iran. 3. Neurosurgery Research Group (NRG), Student Research Committee, Hamadan University of Medical Sciences, Hamadan, Iran. 4. Systematic Review and Meta Analysis Group (SRMEG), Universal Scientific Education and Research Network (USERN), Tehran, Iran. 5. Department of Neurology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 6. Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran. 7. Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. 8. Department of Neurology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. a_tafakhori@sina.tums.ac.ir. 9. Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran. a_tafakhori@sina.tums.ac.ir.
Abstract
BACKGROUND AND OBJECTIVE: Thyroid hormone (TH) disturbances are perceived to contribute to cognitive impairment and dementia. However, there is no consensus on the association between TH levels and Alzheimer Disease (AD). In this study, we aimed to compare serum and cerebrospinal fluid (CSF) TH levels in AD patients to controls by performing a meta-analysis. METHODS: We systematically searched online databases for papers comparing CSF or serum TH levels in AD patients to controls, and performed a meta-analysis on the extracted data. RESULTS: Out of 1604 records identified, 32 studies were included. No significant difference in serum TSH (standardized mean difference (SMD): -0.03; 95% confidence interval (CI): -0.22-0.16), total T4 (SMD: 0.10; 95% CI: -0.29-0.49), and free T4 (SMD: 0.25; 95% CI: -0.16-0.69) levels were observed. However, there was significantly lower serum total T3 (SMD: -0.56; 95%CI: -0.97 to -0.15) and free T3 (SMD: -0.47; 95%CI: -0.89 to -0.05) levels in AD group compared to controls. Subgroup analyses on studies including only euthyroid patients did not show any significant difference in either of the thyroid hormone levels. Also, no significant difference in CSF total T4 and total T3/total T4 ratios but significantly lower CSF total T3 (SMD: -2.45; 95% CI: -4.89 to -0.02) in AD group were detected. CONCLUSION: Serum total and free T3 and CSF total T3 levels are significantly lower in AD patients compared to controls. The temporality of changes in thyroid hormone levels and AD development should be illustrated by further longitudinal studies.
BACKGROUND AND OBJECTIVE: Thyroid hormone (TH) disturbances are perceived to contribute to cognitive impairment and dementia. However, there is no consensus on the association between TH levels and Alzheimer Disease (AD). In this study, we aimed to compare serum and cerebrospinal fluid (CSF) TH levels in AD patients to controls by performing a meta-analysis. METHODS: We systematically searched online databases for papers comparing CSF or serum TH levels in AD patients to controls, and performed a meta-analysis on the extracted data. RESULTS: Out of 1604 records identified, 32 studies were included. No significant difference in serum TSH (standardized mean difference (SMD): -0.03; 95% confidence interval (CI): -0.22-0.16), total T4 (SMD: 0.10; 95% CI: -0.29-0.49), and free T4 (SMD: 0.25; 95% CI: -0.16-0.69) levels were observed. However, there was significantly lower serum total T3 (SMD: -0.56; 95%CI: -0.97 to -0.15) and free T3 (SMD: -0.47; 95%CI: -0.89 to -0.05) levels in AD group compared to controls. Subgroup analyses on studies including only euthyroid patients did not show any significant difference in either of the thyroid hormone levels. Also, no significant difference in CSF total T4 and total T3/total T4 ratios but significantly lower CSF total T3 (SMD: -2.45; 95% CI: -4.89 to -0.02) in AD group were detected. CONCLUSION: Serum total and free T3 and CSF total T3 levels are significantly lower in AD patients compared to controls. The temporality of changes in thyroid hormone levels and AD development should be illustrated by further longitudinal studies.
Authors: Cleusa P Ferri; Martin Prince; Carol Brayne; Henry Brodaty; Laura Fratiglioni; Mary Ganguli; Kathleen Hall; Kazuo Hasegawa; Hugh Hendrie; Yueqin Huang; Anthony Jorm; Colin Mathers; Paulo R Menezes; Elizabeth Rimmer; Marcia Scazufca Journal: Lancet Date: 2005-12-17 Impact factor: 79.321
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Authors: Nicolien A van Vliet; Diana van Heemst; Osvaldo P Almeida; Bjørn O Åsvold; Carole E Aubert; Jong Bin Bae; Linda E Barnes; Douglas C Bauer; Gerard J Blauw; Carol Brayne; Anne R Cappola; Graziano Ceresini; Hannie C Comijs; Jean-Francois Dartigues; Jean-Marie Degryse; Robin P F Dullaart; Marlise E A van Eersel; Wendy P J den Elzen; Luigi Ferrucci; Howard A Fink; Leon Flicker; Hans J Grabe; Ji Won Han; Catherine Helmer; Martijn Huisman; M Arfan Ikram; Misa Imaizumi; Renate T de Jongh; J Wouter Jukema; Ki Woong Kim; Lewis H Kuller; Oscar L Lopez; Simon P Mooijaart; Jae Hoon Moon; Elisavet Moutzouri; Matthias Nauck; Jim Parle; Robin P Peeters; Mary H Samuels; Carsten O Schmidt; Ulf Schminke; P Eline Slagboom; Eystein Stordal; Bert Vaes; Henry Völzke; Rudi G J Westendorp; Michiko Yamada; Bu B Yeap; Nicolas Rodondi; Jacobijn Gussekloo; Stella Trompet Journal: JAMA Intern Med Date: 2021-11-01 Impact factor: 21.873