Changes in thyroid hormones and free triiodothyronine-to-free thyroxine ratio in euthyroid patients with obesity in terms of different glucose metabolism statuses Obezitesi olan ötiroid hastalarda farklı glukoz metabolizması durumlarında tiroid hormonları ve serbest triiodotironin/serbest tiroksin oranı

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Hepşen S., Akhanli P., Sencar M. E., Düger H., Bostan H., Kizilgül M., ...More

Turkish Journal of Endocrinology and Metabolism, vol.25, no.3, pp.279-287, 2021 (ESCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 25 Issue: 3
  • Publication Date: 2021
  • Doi Number: 10.25179/tjem.2021-82919
  • Journal Name: Turkish Journal of Endocrinology and Metabolism
  • Journal Indexes: Emerging Sources Citation Index (ESCI), Scopus, Academic Search Premier, CINAHL, EMBASE, Directory of Open Access Journals, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.279-287
  • Keywords: Diabetes mellitus, fT3/fT4 ratio, obesity, prediabetes, thyroid hormones
  • Open Archive Collection: AVESIS Open Access Collection
  • Ankara Yıldırım Beyazıt University Affiliated: No

Abstract

© 2021 by Society of Endocrinology and Metabolism of Turkey.Objective: The variations of thyroid hormones within normal ranges are observed in different metabolic conditions. Considering available data, levels of thyroid hormones change in obesity and type 2 diabetes mellitus (DM) in opposite ways. This study aimed to evaluate thyroid hormone levels and free triiodothyronine-to-free thyroxine (fT3/fT4) ratios in different glucose metabolism statuses of euthyroid patients with obesity. Material and Methods: This retrospective study evaluated thyroid hormones and the fT3/fT4 ratio of 209 patients with obesity who were grouped according to their glucose metabolism statuses. Results: One hundred and thirty-one (62.7%) patients had normal glucose tolerance, 41 (19.6%) patients had pre-diabetes, and 37 (17.7%) patients had DM. Serum fT4 level was found to be higher in patients with DM compared to patients with normal glucose tolerance (p=0.009), although no difference was observed in serum thyroid-stimulating hormone and fT3 levels among groups. FT3/fT4 ratio was determined to be lower in patients with DM than patients with normal glucose tolerance (p=0.012). Hemoglobin A1c was independently and positively associated with fT4 (β=0.345, r2=0.119, p=0.003) and negatively associated with fT3/fT4 ratio (β=-0.371, r2=0.138, p=0.001). Conclusion: Serum fT4 level increased, and fT3/fT4 ratio decreased in patients with type 2 DM independent of the degree of obesity. The interaction of DM with thyroid hormones in our cohort seemed to overcome obesity-related changes in thyroid functions.