title: Circulating levels of irisin is elevated in hypothyroidism, a case-control study.
abstract: Objective Our objective in this study was to determine the relationship between irisin hormone, which has a similar effect with thyroid hormones on adipose tissue and the metabolism, and the thyroid functions and the obesity secondary to thyroid disease. Subjects and methods Seventy-four patients were included in the study, of the patients, 37 were newly diagnosed with Hashimoto's thyroiditis related hypothyroidism but not started on a treatment yet, and the remaining 37 were healthy volunteers without a known disease. Serum thyroid stimulating hormone (TSH), free thyroxin (fT4), anti-thyroglobulin and anti-thyroid peroxidase were measured and thyroid ultrasonography was performed in both groups. Serum irisin levels were measured using the commercially available ELISA kit. The hypothyroidism group had higher levels of irisin compared to the control group (2.77 ng/mL vs. 2.15 ng/mL respectively; p = 0.017). Results The hypothyroidism group had higher median levels of irisin in the obese patients than those in the control group (3.10 ng/mL vs. 2.10 ng/mL respectively; p = 0.013). Irisin level was negatively correlated with age in the whole population and patients with hypothyroidism (r = -0.255, p = 0.028; r = -0.346, p = 0.036 respectively). Irisin level was positively correlated with TSH (r = 0.247, p = 0.034) but negatively correlated with the fT4 (r = -0.316, p = 0.006) in the whole population. Obesity, fT4 and irisin levels were identified to be independent predictors in the diagnosis of hypothyroidism in the multivariable logistic regression analysis. Conclusion To the best of our knowledge, this study is the first in literature to identify that obesity, irisin level and fT4 level are independent risk factors for hypothyroidism.
authors.affiliation: Department of Internal Medicine, Ankara Numune Education and Research Hospital, Ankara, Turkey.
authors.forename: İhsan
authors.initials: İ
authors.lastname: Ateş
authors.affiliation: Department of Internal Medicine, Ankara Numune Education and Research Hospital, Ankara, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Altay
authors.affiliation: Department of Biochemistry, Ankara Numune Education and Research Hospital, Ankara, Turkey.
authors.forename: Canan
authors.initials: C
authors.lastname: Topçuoğlu
authors.affiliation: Department of Biochemistry, Ankara Numune Education and Research Hospital, Ankara, Turkey.
authors.forename: Fatma Meriç
authors.initials: FM
authors.lastname: Yılmaz
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000328:Adult; D001323:Autoantibodies / Q000097:blood; D001794:Blood Pressure / Q000502:physiology; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005353:Fibronectins / Q000097:blood*; D050031:Hashimoto Disease / Q000097:blood* / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D007037:Hypothyroidism / Q000097:blood* / Q000150:complications / Q000503:physiopathology*; D007453:Iodide Peroxidase / Q000097:blood; D016015:Logistic Models; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000209:etiology / Q000503:physiopathology*; D012016:Reference Values; D012307:Risk Factors; D018709:Statistics, Nonparametric; D013961:Thyroid Gland / Q000378:metabolism / Q000503:physiopathology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
chemical_list: D001323:Autoantibodies; C577593:FNDC5 protein, human; D005353:Fibronectins; C006606:anti-thyroglobulin; D013972:Thyrotropin; D007453:Iodide Peroxidase; D013974:Thyroxine