Obezitede TSH düzeyleri ve Vücut Kompozisyonu

Öz

Amaç: Bu çalışma,eutiroid yetişkinlerde vücut kitle indeksi(VKİ) kategorileri arasında serum tiroid uyarıcı hormon (TSH) düzeylerini karşılaştırmayı ve TSH ile viseral yağderecesi, metabolik yaş, sıvı yüzdesi ve kas kütlesi gibi ayrıntılı vücut kompozisyonu parametreleri arasındaki ilişkileriaraştırmayı amaçlamıştır. Gereç ve Yöntem: Buretrospektif kesitsel çalışma, 2024 yılında bir üniversite hastanesininiç hastalıkları polikliniğine başvuran 119 ötiroid yetişkini içermektedir. BMIölçülen boy ve kilo kullanılarak hesaplandı ve zayıf(<18,5 kg/m²), normal kilo (18,5–24,9 kg/m²), fazla kilo (25–29,9 kg/m²)ve obez (≥30 kg/m²) olarak sınıflandırıldı. Vücut kompozisyonu parametreleri; viseral yağ derecesi,metabolik yaş, sıvı yüzdesi ve kas kütlesi; TanitaBC-418 biyoelektrik empedans analizörü kullanılarak değerlendirildi. Serum TSH ve laboratuvar parametrelerihastane elektronik kayıtlarından alındı. Grup karşılaştırmalarıtek yönlü ANOVA ve post-hoc Tukey testleri kullanılarak yapıldı. TSH ve vücut kompozisyonu arasındaki ilişkiler Spearman sıralama korelasyonu kullanılarak analiz edildi. Bulgular: Katılımcıların ortalama yaşı 32,5±13,7 idi ve %63,9'u kadındı. Genel ortalama BMI 25,5±5,6 kg/m² ve ortalama TSH 1,71±0,99 μIU/mL idi. TSH düzeyleri BMI grupları arasında kademeli olarak artmıştır: zayıf grupta 1,25±0,48 μIU/mL, normal kilo grubunda 1,49±0,70 μIU/mL, 1,91±1,11 μIU/mL, obez grupta 2,21±1,29 μIU/mL (ANOVAF(3,115)=4,20, p=0,007). Post-hoc analizler, obez bireylerde zayıf (p=0,033) ve normal kilolu katılımcılara (p=0,027) kıyasla anlamlı olarak daha yüksek TSH düzeyleri olduğunu göstermiştir. Spearman korelasyon analizleri, TSH ile viseral yağ derecesi (ρ=0,24, p=0,008), metabolik yaş (ρ=0,24, p=0,011) ve kas kütlesi (ρ=0,18, p=0,047) ile pozitif bir ilişki olduğunu ve sıvı yüzdesi (ρ=–0,23, p=0,011) ile negatif bir ilişki olduğunu ortaya koydu. Sonuç: Referans aralığı içindeki yüksek TSH düzeyleri, obezite ve artmış viseral yağlanma, yüksek metabolik yaş, düşük sıvı yüzdesi ve azalmış kas kütlesi gibi olumsuz vücut kompozisyonu parametreleri ile ilişkilidir. Bu bulgular, ötiroid yetişkinlerde TSH düzeylerini yorumlarken vücut kompozisyonunun BMI'nin ötesinde ek bilgiler sağlayabileceğini göstermekte ve ayrıntılı kompozisyon ölçütlerinin metabolik ve endokrin değerlendirmelere dahil edilmesinin potansiyel klinik önemini vurgulamaktadır.

Anahtar Kelimeler

• Obezite
• tiroid hormonları
• metabolik yaş

TSH LEVELS AND BODY COMPOSITION IN OBESITY

Öz

Objective: This study aimed to compare serum thyroid- stimulating hormone (TSH) levels across body mass index (BMI) categories in euthyroid adults and to investigate the associations between TSH and detailed body composition parameters, including visceral fat rating, metabolic age, fluid percentage, and muscle mass. Material and Methods: This retrospective cross-sectional study included 119 euthyroid adults who attended the internal medicine outpatient clinic of a university hospital in 2024. BMI was calculated using measured height and weight and categorized as underweight (<18.5 kg/m²), normal weight (18.5–24.9 kg/m²), overweight (25–29.9 kg/m²), and obese (≥30 kg/m²). Body composition parameters: visceral fat rating, metabolic age, fluid percentage, and muscle mass; were assessed using a Tanita BC-418 bioelectrical impedance analyzer. Group comparisons were performed using one-way ANOVA with post-hoc Tukey tests. Associations between TSH and body composition were analyzed using Spearman rank correlation. Results:The mean age of participants was 32.5±13.7 years, and 63.9% were female. Mean BMI was 25.5±5.6 kg/m², and mean TSH was 1.71±0.99 μIU/mL. TSH increased across BMI groups: 1.25±0.48 μIU/mL in underweight, 1.49±0.70 μIU/mL in normal weight, 1.91±1.11 μIU/mL in overweight, and 2.21±1.29 μIU/mL in obese individuals (ANOVA F(3,115)=4.20, p=0.007). Post-hoc analyses showed higher TSH in obese individuals than underweight (p=0.033) and normal-weight participants (p=0.027). Spearman analyses showed positive correlations between TSH and visceral fat rating (ρ=0.24, p=0.008), metabolic age (ρ=0.24, p=0.011), muscle mass (ρ=0.18, p=0.047), and a negative correlation with fluid percentage (ρ=–0.23, p=0.011). Conclusion: Higher TSH levels within the reference range are associated with obesity and unfavourable body composition parameters, including increased visceral adiposity, higher metabolic age, lower fluid percentage, and reduced muscle mass. These findings suggest that body composition may provide insight beyond BMI when interpreting TSH levels in euthyroid adults and highlight the clinical relevance of incorporating detailed composition metrics into metabolic and endocrine assessments.

Anahtar Kelimeler

• Obesity
• thyroid hormones
• metabolic age

Kaynakça

1. Perdomo CM, Cohen RV, Sumithran P, Clément K, Frühbeck G. Contemporary medical, device, and surgical therapies for obesity in adults. Lancet. 2023;401(10382):1116-1130.
2. Powell-Wiley TM, Poirier P, Burke LE, et al. Obesity and cardiovascular disease: A scientific statement from the american heart association. Circulation. 2021;143(21):e984-e1010.
3. Omma A, Erden F, Çolak SY, et al. Is the visceral adiposity index associated with the presence of cardiovascular risk scores and comorbidity in psoriatic disease? J Turk Soc Rheumatol. 2024;16(3):90-96.
4. Pandey A, Patel KV, Segar MW, et al. Effect of liraglutide on thigh muscle fat and muscle composition in adults with overweight or obesity: Results from a randomized clinical trial. J Cachexia Sarcopenia Muscle. 2024;15(3):1072-1083.
5. Walczak K, Sieminska L. Obesity and thyroid axis. Int J Environ Res Public Health. 2021;18(18):9434.
6. Biondi B. Subclinical hypothyroidism in patients with obesity and metabolic syndrome: A narrative review. Nutrients. 2023;16(1):87.
7. Song RH, Wang B, Yao QM, Li Q, Jia X, Zhang JA. The ımpact of obesity on thyroid autoimmunity and dysfunction: A systematic review and meta-analysis. Front Immunol. 2019;10:2349.
8. Teixeira PFDS, Dos-Santos PB, Pazos-Moura CC. The role of thyroid hormone in metabolism and metabolic syndrome. Ther Adv Endocrinol Metab. 2020;11:2042018820917869.

9. Cordido M, Juiz-Valiña P, Urones P, Sangiao-Alvarellos S, Cordido F. Thyroid function alteration in obesity and the effect of bariatric surgery. J Clin Med. 2022;11(5):1340.
10. Salmón-Gómez L, Catalán V, Frühbeck G, Gómez-Ambrosi J. Relevance of body composition in phenotyping the obesities. Rev Endocr Metab Disord. 2023;24(5):809-823.
11. Reinehr T. Obesity and thyroid function. Mol Cell Endocrinol. 2010;316(2):165-171.
12. Rotondi M, Leporati P, La Manna A, et al. Raised serum TSH levels in patients with morbid obesity: Is it enough to diagnose subclinical hypothyroidism?. Eur J Endocrinol. 2009;160(3):403-408.
13. Tian Z, Nie Y, Li Z, et al. Total weight loss induces the alteration in thyroid function after bariatric surgery. Front Endocrinol (Lausanne). 2024;15:1333033.
14. Nannipieri M, Cecchetti F, Anselmino M, et al. Expression of thyrotropin and thyroid hormone receptors in adipose tissue of patients with morbid obesity and/or type 2 diabetes: Effects of weight loss. Int J Obes (Lond). 2009;33(9):1001-1006.
15. Le Moli R, Vella V, Tumino D, et al. Inflammasome activation as a link between obesity and thyroid disorders: Implications for an integrated clinical management. Front Endocrinol (Lausanne). 2022;13:959276.
16. Pleić N, Gunjača I, Babić Leko M, Zemunik T. Thyroid function and metabolic syndrome: A two-sample bidirectional mendelian randomization study. J Clin Endocrinol Metab. 2023;108(12):3190-3200.
17. Wei Y, Yang M, Liu J, Wang Y, Wang G. Associations between sensitivity to thyroid hormones and visceral adiposity in euthyroid adults. J Clin Endocrinol Metab. 2025;110(8):e2744-e2753.
18. Le Moli R, Malandrino P, Russo M, et al. Levothyroxine therapy, calculated deiodinases activity and basal metabolic rate in obese or nonobese patients after total thyroidectomy for differentiated thyroid cancer, results of a retrospective observational study. Endocrinol Diabetes Metab. 2023;6(2):e406.
19. Walsh JP. Thyroid function across the lifespan: Do age-related changes matter? Endocrinol Metab (Seoul). 2022;37(2):208-219.
20. Mohamed E, Nashed A, Abo Elainin M, Osman D. Effect of body composition on thyroid hormones in euthyroid post-pubertal females: An observational study. Egyptian J Phys Ther. 2022;9(1):9-14.
21. Armstrong LE, Muñoz CX, Armstrong EM. Distinguishing low and high water consumers-a paradigm of disease risk. Nutrients. 2020;12(3):858.
22. Nappi A, Moriello C, Morgante M, Fusco F, Crocetto F, Miro C. Effects of thyroid hormones in skeletal muscle protein turnover. J Basic Clin Physiol Pharmacol. 2024;35(4-5):253-264.