Özet:

Aim: The high prevalence of nodular goiter in patients with acromegaly is well known. Insulin-like growth factor-1 (IGF-1) has been claimed to be one of the etiologic factors. The aim of the study was to evaluate the incidence of thyroid lesions in our acromegalic patients and to analyze possible factors influencing thyroid nodule development, especially insulin resistance and hormonal parameters. Material and Methods: Sixty patients with acromegaly, 32 females, and 28 males, with a mean age of 52.7 ± 10.0 years without known thyroid disease were included. Age and sex matched 100 control subjects also included in the study. Waist and hip circumference, weight, and height, fasting blood glucose, postprandial blood glucose, insulin, thyroid function tests, thyroid autoantibodies, lipid profile, IGF-1, growth hormone, other anterior pituitary hormone levels were measured in all patients. Magnetic Resonance Imaging (MRI) and thyroid ultrasonography (US) was performed in all patients. Thyroid nodule volume and thyroid volume were calculated. Results: Thirty-five (58.3%) patients with acromegaly had thyroid nodules according to (% 25) in control group (p<0,0001). There were significant differences in BMI, thyroid volume, fasting glucose and TSH levels between patients and controls. After regression analysis, thyroid volume was associated with insulin, waist circumference, HOMA-IR, LDL-cholesterol and the size of the pituitary adenoma (p<0.05) or diabetes occurrence. During the logistic regression analysis, the presence of nodules was strongly associated with luteinizing hormone (LH) (p<0.02) and HDL-cholesterol levels (p<0.05). Nodule volume were significantly associated with LH level (p<0.05), ACTH (beta = -0.51, p< 0.01), plasma cortisol (beta= 0.965, p <0.05), free T4 (beta= 0.522, p<0.05), the size of adenoma (beta= 0.615, p<0.05) in the regression analysis. Conclusion: The prevalence of nodules in acromegalic patients were found to be higher than usual prevalence. In addition to IGF-1, other hormones and insulin resistance might play an important role in thyroid volume, nodule volume, and nodule formation mechanism in patients with acromegaly.

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