Obezitenin tiroid fonksiyonu üzerindeki etkisi: Hiperinsülinemi ve inflamasyonun rolleri

Year 2025, Volume: 42 Issue: 4, 372 - 377, 31.12.2025

Banu Açmaz , Sami Bahçebaşı

Abstract

Project Number

117

The impact of obesity on thyroid function: Roles of hyperinsulinemia and inflammation

Abstract

Obesity results from an imbalance between energy intake and expenditure, with thyroid hormones crucial in regulating metabolism and energy balance. A bidirectional relationship between obesity and thyroid hormones exists, but the effect of hyperinsulinemia on the thyroid axis remains unclear This research involved a retrospective evaluation of 486 individuals classified as overweight or obese (BMI ≥25 kg/m² and BMI ≥30 kg/m²), partitioned into groups depending on the presence of hyperinsulinemia. In addition, 42 healthy individuals without obesity or chronic illnesses were enrolled as the control group. Comparisons were made among the groups regarding thyroid-stimulating hormone (TSH), liver function markers, lipid profiles, and CRP levels. Participants were categorized into three groups based on BMI: normal weight (control), overweight, and obese. Higher BMI was associated with significant increases in HbA1c, ALT, LDL, and TG levels (p<0.001, p=0.016, p=0.052, p=0.001, respectively), while HDL levels decreased significantly (p<0.001). TSH levels were significantly higher in obese individuals compared to the overweight and normal-weight groups (p = 0.026). CRP, glucose, and insulin levels were also significantly elevated in the overweight and obese groups (p<0.001 for all). When overweight and obese participants were further classified based on insulin resistance (HOMA-IR>2.5 vs. <2.5), the insulin-resistant group exhibited significantly higher HbA1c, AST, ALT, TG, and CRP levels (p = 0.026, p = 0.036, p = 0.001, p = 0.036, respectively). Additionally, TSH levels were significantly elevated in insulin-resistant individuals (p = 0.023). Higher BMI was associated with metabolic disturbances, including increased 3 HbA1c, ALT, LDL, TG, and TSH levels, along with decreased HDL. Insulin resistance further worsened these parameters, accompanied by significantly higher CRP and TSH levels. The observed CRP elevation suggests that inflammation driven by hyperinsulinemia may contribute to thyroid dysfunction. Clinically, monitoring HOMA-IR and routinely assessing TSH in obese patients may help predict and manage early thyroid abnormalities.

Keywords

Obesity , thyroid-stimulating hormone , insulin resistance , inflammation , Body Mass Index

Ethical Statement

kayseri city hospital non invazive ethics comitee

Project Number

117

Thanks

We sincerely thank the Radiology Department for their support and contributions to this publication.

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