TSH LEVELS AND BODY COMPOSITION IN OBESITY

Authors : Fatma Zehra Ağan, Çiğdem Cindoğlu, Derya Abuşka

Pages : 386-391

Doi:10.24938/kutfd.1807235

View : 60 | Download : 151

Publication Date : 2025-12-25

Article Type : Research Paper

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 : Obezite, tiroid hormonları, metabolik yaş

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