Alterations of Thyroid Functions in Obesity: Is There any Impact of Co-Existence of Type 2 Diabetes Mellitus?

Abstract

Aim: Little is known about the effect of coexistent type 2 diabetes mellitus (DM) on thyroid functions in obesity. We aimed to evaluate the thyroid function in the both diabetic and nondiabetic obese patients.

Materials and Methods: 145 obese patients admitted to our department, between June 2014 and May 2016, were included in the study. The patients with known thyroid dysfunction were excluded from the study. The patients were grouped according to their BMI (body mass index), co-existence of type 2 DM, and TSH (thyroid stimulating hormone). Data were collected retrospectively and analyzed.

Results: No difference was observed between diabetic and nondiabetic groups for the mean age, body weight, fT3 (free T3), fT4 (free T4), BMI, TSH. Primary hypothyroidism, subclinical hypothyroidism and hyperthyroidism were determined in 1.4, 0.7 and 2.8 % of the patients, respectively; no difference was found between diabetic and nondiabetic groups (p=0.588). There was no significant correlation between BMI and TSH (r=0.030, p=0.717).Distribution of patients in different TSH groups between diabetic and nondiabetic groups were similar (p=0.533). There were positive correlations between BMI and, fT4 or fT3 (r=0.274, p=0.001; r=0.280, p=0.002; respectively). Although 1.4% of all patients had isolated elevation of fT4, there was no difference between groups (p=0.178). 24.6% of diabetic, 28.4% of nondiabetic and 26.6% of all patients had isolated elevation of fT3; however, no difference was found (p=0.634).

Conclusions: Our study suggested that obesity could be associated with elevated fT4 and fT3. Elevation of fT3 and fT4 with increasing BMI may be as response to increased metabolic rate. We found no difference between diabetic and nondiabetic groups concerning to fT4 and fT3 elevation. As a result, co–existence of type 2 DM seems to have no effect on thyroid functions.

Keywords

• Obesity,Thyroid function,Diabetes mellitus

Obezitede Tiroid Fonksiyonlarının Değişimi: Tip 2 Diabetes Mellitus’un Birlikte Varlığının Bir Etkisi var mı?

Abstract

Amaç: Eşlik eden tip 2 diabetes mellitus (DM)’un obezitede tiroid fonksiyonları üzerindeki etkilerine ilişkin az şey bilinmektedir. Biz, diyabetik ve nondiyabetik obez hastalarda tiroid fonksiyonlarını değerlendirmeyi amaçladık.

Gereç ve Yöntemler: Haziran 2014 ile Mayıs 2016 arasında kliniğimize başvuran 145 obez hasta çalışmamıza dahil edildi. Bilinen tiroid disfonksiyonu olan hastalar çalışmadan dışlandı. Hastalar vücut kitle indeksi (VKİ), eşlik eden tip 2 DM varlığı ve TSH (tiroid stimuli edici hormon) değerlerine göre gruplandırıldılar. Veriler retrospektif olarak toplandı ve analiz edildi.

Bulgular: Ortalama yaş, vücut ağırlığı, sT3 (serbest T3), sT4 (serbest T4), VKİ, TSH değerleri açısından diyabetik ve nondiyabetik gruplar arasında fark saptanmadı. Hastaların %1.4’ünde primer hipotiroidi, %0.7’sinde subklinik hipotiroidi ve %2.8’inde hipertiroidi saptandı; diyabetik ve nondiyabetik gruplar arasında fark saptanmadı (p=0.588). VKİ ile TSH arasında anlamlı bir korelasyon saptanmadı (r=0.030, p=0.717). Farklı TSH gruplarının diyabetik ve nondiyabetik gruplar arasındaki dağılımı benzerdi (p=0.533). VKİ ile sT4 veya  sT3 arasında pozitif korelasyon mevcuttu (sırasıyla: r=0.274, p=0.001; r=0.280, p=0.002). Hastaların %1.4’ünde izole sT4 yüksekliği saptanırken, gruplar arasında anlamlı bir fark saptanmadı (0.178). Diyabetik grubun %24.6’sında, nondiyabetik grubun % 28.4’inde ve tüm hastaların % 26.6’sında izole sT3 yüksekliği saptandı; ancak gruplar arasında fark saptanmadı (p=0.634).

Sonuç: Çalışmamız obezitenin sT4 ve sT3 yüksekliği ile ilişkili olabildiğini destekledi. VKİ artışıyla sT3 ve sT4 değerlerinin artışı artmış metabolik hıza cevap olarak geilşebilir. Diyabetik ve nondiyabetik gruplar arasında sT4 ve sT3 yüksekliğine ilişkin bir fark saptanmadı. Sonuç olarak, eşlik eden tip 2 DM’nin varlığının tiroid fonksiyonları üzerinde etkisi izlenmedi.

Keywords

• Obezite,Tiroid fonksiyonu,Diabetes mellitus

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