Clinical Interventions in Aging (Aug 2023)

TT3, a More Practical Indicator for Evaluating the Relationship Between Sarcopenia and Thyroid Hormone in the Euthyroid Elderly Compared with FT3

  • Chen J,
  • Wei L,
  • Zhu X,
  • Xu W,
  • Zou Y,
  • Qi X,
  • Fang J,
  • Wang X,
  • Shi X,
  • Sheng Y,
  • Ding G,
  • Ouyang X,
  • Duan Y

Journal volume & issue
Vol. Volume 18
pp. 1285 – 1293

Abstract

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Jihai Chen,1,2 Lijun Wei,2 Xiaoxia Zhu,2 Wenli Xu,2 Yuxin Zou,2 Xinyu Qi,2 Jia Fang,2 Xiaodong Wang,2 Xiaolan Shi,1 Yunlu Sheng,2 Guoxian Ding,2 Xiaojun Ouyang,1 Yu Duan2 1Department of Geriatric, Geriatric Hospital of Nanjing Medical University, Nanjing, 210024, People’s Republic of China; 2Department of Geriatric Endocrinology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, People’s Republic of ChinaCorrespondence: Yu Duan, Department of Geriatric Endocrinology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, 210029, People’s Republic of China, Email [email protected] Xiaojun Ouyang, Department of Geriatric, Geriatric Hospital of Nanjing Medical University, Luojia Road 30, Nanjing, 210024, People’s Republic of China, Email [email protected] and Aims: Sarcopenia is a common disease in the elderly, and the thyroid hormone (TH) might participate in the pathogenesis of sarcopenia. However, the results of previous studies were not completely consistent. We performed this study to investigate the association between THs and sarcopenia in a Chinese elderly euthyroid population.Subjects and Methods: A total of 309 Chinese elderly euthyroid subjects with an average age of 85.19 ± 7.8 years were enrolled. Participants were divided into four groups (non-sarcopenia, possible sarcopenia, sarcopenia and serve sarcopenia) according to the consensus update of AWGS in 2019. Serum levels of TT3, FT3, TT4, FT4, TSH, rT3 and TBG were measured. Muscle mass was measured by multifrequency bioelectrical impedance analysis, hand grip (HG) was represented by spring-type dynamometer, and gait speed (GS) was determined by 6-metre walk test. The FRAIL scale was used to assess frailty.Results: Compared to the non-sarcopenia group, the sarcopenia group showed a significant increase in age and FRIAL score, while FT3 and TT3 levels decreased significantly. Partial correlation analysis (adjusted by age, gender and the scores of FRIAL scale) indicated that FT3, TT3 and TSH had significant positive correlations with HG, and there also was a significant positive correlation between TT3 and GS. In addition, after adjusting for age, gender, BMI, ALT, sCr, and score on the FRAIL scale, the multivariate linear regression analysis showed that TT3 was positively associated with muscle strength and negatively associated with sarcopenia risk.Conclusion: There is an association between the low TT3 level and sarcopenia. Therefore, maintaining higher T3 concentrations within the normal range appears to be beneficial for sarcopenia in the elderly. In addition, due to the fluctuation of FT3, TT3 is a more stable and practical indicator to evaluate the relationship between sarcopenia and thyroid hormone in the elderly euthyroid population.Graphical Abstract: Keywords: sarcopenia, thyroid hormone, elderly, muscle strength

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