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

Year 2018, Volume: 2 Issue: 1, 23 - 27, 01.04.2018

Ömercan Topaloğlu , Fatih Sümer Sedat Çetın Saim Yoloğlu Cüneyt Kayaalp İbrahim Şahın

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

References

• 1. Satman I, et al. TURDEP-II Study Group. Twelve-year trends in the prevalence and risk factors of diabetes and prediabetes in Turkish adults. Eur J Epidemiol. 2013;28(2):169-180.
• 2. Bemben DA, et al. Thyroid disease in the elderly. Part 2. Predictability of subclinical hypothyroidism. J FamPract. 1994;38:583.
• 3. Tunbridge WM, et al. The spectrum of thyroid disease in a community: The whickham survey. Clin Endocrinol (Oxf). 1977;7:481.
• 4. Bagchi N, et al. Thyroid dysfunction in adults over age 55 years. A study in an urban US community. Arch Intern Med. 1990;150:785.
• 5. Kanaya AM, et al. Association between thyroid dysfunction and total cholesterol level in an older biracial population: The health, aging and body composition study. Arch Intern Med. 2002;162:773.
• 6. Canaris GJ, et al. The colorado thyroid disease prevalence study. Arch Intern Med. 2000;160:526.
• 7. Parle JV, et al. Prevalence and follow-up of abnormal thyrotrophin (TSH) concentrations in the elderly in the United Kingdom. ClinEndocrinol (Oxf). 1991;34:77.
• 8. Montoya-Morales DS, et al. Alterations of the thyroid function in patients with morbid obesity. Rev Med InstMexSeguro Soc. 2015;53(Suppl 1):S18-22.
• 9. Bouglé D, et al. Thyroid function and metabolic risk factors in obese youth. Changes during follow-up: A preventive mechanism? Exp Clin Endocrinol Diabetes. 2014;122(9):548- 552.
• 10. Michalaki MA, et al. Thyroid function in humans with morbid obesity. Thyroid. 2006;16(1):73-78.
• 11. Knudsen N, et al. Small differences in thyroid function may be important for body mass index and the occurrence of obesity in the population. J Clin Endocrinol Metab. 2005;90(7):4019- 4024.
• 12. Muscogiuri G, et al. High-normal TSH values in obesity: Is it insulin resistance or adipose tissue’s guilt? Obesity (Silver Spring). 2013;21(1):101-106.
• 13. Shon HS, et al. Free T4 is negatively correlated with body mass index in euthyroid women. Korean J Intern Med. 2008;23(2):53-57.
• 14. Iacobellis G, et al. Relationship of thyroid function with body mass index, leptin, insulin sensitivity and adiponectin in euthyroid obese women. Clin Endocrinol (Oxf). 2005;62(4):487-491.
• 15. Manji N, et al. Lack of association between serum TSH or free T4 and body mass index in euthyroid subjects. Clin Endocrinol (Oxf). 2006;64(2):125-128.
• 16. Kommareddy S, et al. Thyroid function and metabolic syndrome: A cross-sectional study in obese and overweight patients. Endocr Pract. 2015;21(11):1204-1210.