ISSN: 1301-2193 E-ISSN: 1308-9846
  • Turkish Journal of
    Endocrinology and Metabolism

Obesity is Associated with Increased Thyroid Volume and Heterogeneity in Ultrasonography
Obezite Tiroid Ultrasonografisinde Artmış Tiroid Volümü ve Heterojeniteyle İlişkilidir
Received Date : 26 Aug 2019
Accepted Date : 12 Mar 2020
Available Online : 24 Oct 2020
Ankara Yıldırım Beyazıt University Faculty of Medicine, Department of Endocrinology and Metabolism, Ankara, Turkey *Ankara Yıldırım Beyazıt University Faculty of Medicine, Department of Biostatistics, Ankara, Turkey
Doi: 10.25179/tjem.2019-71171 - Makale Dili: EN
Turk J Endocrinol Metab 2020;24:9-15
ABSTRACT
Objective: The aim of the present study was to investigate the possible association between obesity and thyroid functions and thyroid morphology. Material and Methods: A total of 674 subjects-121 obese and 553 nonobese-were included in the study. Body mass index, serum thyrotrophic, free triiodothyronine (fT3), free thyroxine (fT4), antithyroid peroxidase antibody, and antithyroglobulin antibody (antiTg) were evaluated in each subject. The subjects with thyroid nodules in ultrasonography (USG) were excluded. The thyroid volume of each subject was calculated and analyzed. Results: Obesity was significantly associated with increased age and low fT4 in univariate analysis (p<0.05). With multivariate analysis, the odds of obesity was found to increase by 21.8% (95% CI: 12.4-31.9%) for each 5-year increase in age anddecrease by 53.1% (95% CI: 0.4-77.9%) for each 1 ng/dL increase in fT4. The odds of obesity in patients with positive antiTg was 1.603 (95% 1.047-2.454) times higher than the odds of obesity in patients with negative antiTg. The median total thyroid volume was significantly higher in obese as compared to nonobese subjects (12.11 mL vs. 10.77 mL, p<0.001). Heterogeneous gland with negative thyroid antibodies was observed in 17 (14%) obese and 40 (7.2%) nonobese subjects (p=0.024). Conclusion: Obesity was positively associated with antiTg and age, whereas negatively associated with fT4. Approximately, in every seven obese subjects, one showed heterogeneity in US despite negative thyroid autoantibodies. This suggests that the value of US in the diagnosis of autoimmune thyroiditis might decrease in obese patients.
ÖZET
Amaç: Obezite ile tiroid fonksiyonları ve tiroid morfolojisi arasındaki muhtemel ilişkiyi araştırmaktır. Gereç ve Yöntemler: Çalışmaya toplam 121’i obez 553’ü nonobez olmak üzere 674 birey alındı. Her bireyde beden kitle indeksi, serum tirotiropin, serbest triodotironin (sT3), serbest tiroksin (sT4), antitiroid peroksidaz antikoru ve antitiroglobulin antikoru (antiTg) değerlendirildi. Ultrasonografi (USG) de tiroid nodülü olanlar çalışma dışında bırakıldı. Her bireyde tiroid volümü hesaplandı ve analiz edildi. Bulgular: Univariate analizde obezite anlamlı olarak artan yaş ve düşük sT4 ile ilişkiliydi (p<0,05). Multivariate analizde obezite riski yaşta artan her 5 yıl için %21,8 (%95 güven aralığı (GA): %12,4-31,9) ve sT4’teki her bir ng/dL azalışta %53,1 (%95 GA: %0,4-77,9) artmaktaydı. AntiTg negatif hastalara göre antiTg pozitif olan hastalarda obezite riski 1,603 (%95 1,047-2,454) kat daha fazlaydı. Obezlerde nonobezlere göre median total tiroid volümü anlamlı olarak daha fazlaydı (12,11 mL’ye karşı 10,77 mL, p<0,001). Heterojen glandıyla birlikte tiroid antikorlarının negatifliği 17 (%14) obez ve 40 (%7,2) nonobez bireyde tespit edildi (p=0,024). Sonuç: Obezite antiTg ve yaş ile pozitif ve sT4 ile negatif olarak ilişkiliydi. Obezitesi olan yaklaşık olarak her 7 bireyin birinde tiroid antikorları negatif olmasına rağmen USG’de heterojenite vardı. Bu bize, obez hastalarda otoimmün tiroidit tanısında USG'nin değerinin azalabileceğini göstermektedir.
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