Metabolic parameters are associated with thyroid volume and free T3 levels in euthyroid individuals: a cross-sectional study

Abstract

Aims: Our study aimed to investigate the impact of metabolic parameters, specifically insulin level and body-mass index (BMI), on the thyroid gland, considering both morphological and functional aspects. For this purpose, we performed a cross-sectional analysis with euthyroid participants. Methods: One hundred euthyroid adults without thyroid autoimmunity or nodules were included. Thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), fasting insulin levels (FPI), and glucose/insulin values from a 2-hour OGTT were recorded. Anthropometric measures, including BMI and waist circumference (WC), were obtained, and thyroid volume (TV) was measured by ultrasound. The relationship between TV, hormone levels, and metabolic parameters was analyzed. Results: A significant positive relationship was observed between TV and multiple parameters, including BMI, HOMA-IR, HbA1c, FPG, and FPI. Regression modeling identified OGTT 2nd-hour insulin and WC as significant predictors of thyroid volume. Furthermore, FT3 concentrations correlated positively with BMI, WC, HOMA-IR, and FPI measurements. Conclusion: Increased TV appears to be associated with obesity and higher HOMA-IR, whereas FT3 levels show a positive correlation with both. These findings imply a significant interplay between insulin level, adiposity, thyroid gland morphology, and thyroid hormone metabolism.

Keywords

• Thyrotropin
• triiodothyronine
• glucose tolerance test
• ultrasonography
• glycated hemoglobin

Metabolik parametreler, ötiroid bireylerde tiroid hacmi ve serbest T3 seviyeleri ile ilişkilidir: kesitsel bir çalışma

Abstract

Amaç: Çalışmamız, metabolik parametrelerin—özellikle insülin düzeyi ve vücut kitle indeksi (VKİ)—tiroid bezi üzerindeki etkisini, hem morfolojik hem de fonksiyonel açıdan incelemeyi amaçlamıştır. Bu amaçla, ötiroid katılımcılarla kesitsel bir analiz yapılmıştır. Yöntemler: Tiroid otoimmünitesi veya nodülü olmayan 100 ötiroid erişkin çalışmaya dahil edildi. Tiroid uyarıcı hormon (TSH), serbest triiyodotironin (FT3), serbest tiroksin (FT4), açlık plazma glukozu (APG), glike hemoglobin (HbA1c), açlık insülini (FPI) ve 2 saatlik OGTT’den elde edilen glukoz/insülin değerleri kaydedildi. VKİ ve bel çevresi (BÇ) dahil antropometrik ölçümler alındı ve tiroid hacmi (TH) ultrasonografi ile değerlendirildi. TH, hormon düzeyleri ve metabolik parametreler arasındaki ilişki analiz edildi. Bulgular: TH ile VKİ, HOMA-IR, HbA1c, APG ve FPI dahil birçok parametre arasında anlamlı pozitif ilişki bulundu. Regresyon analizinde OGTT 2. saat insülin düzeyi ve BÇ, tiroid hacminin anlamlı belirleyicileri olarak ortaya çıktı. Ayrıca FT3 düzeyleri, VKİ, BÇ, HOMA-IR ve FPI ölçümleri ile pozitif korelasyon gösterdi. Sonuç: Artmış tiroid hacmi, obezite ve daha yüksek HOMA-IR ile ilişkili görünmektedir; FT3 düzeyleri ise her ikisiyle pozitif korelasyon göstermektedir. Bu bulgular, insülin düzeyi, adipozite, tiroid bezi morfolojisi ve tiroid hormon metabolizması arasında anlamlı bir etkileşim olduğunu düşündürmektedir.

Keywords

• Tirotropin
• triiyodotironin
• glukoz tolerans testi
• ultrasonografi
• glike hemoglobin

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