Obezitede TSH düzeyleri ve Vücut Kompozisyonu

Abstract

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.

Keywords

• Obezite
• tiroid hormonları
• metabolik yaş

TSH LEVELS AND BODY COMPOSITION IN OBESITY

Abstract

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.

Keywords

• Obesity
• thyroid hormones
• metabolic age

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