High Body Mass Index and Thyroid Stimulating Hormone Levels Do Not Affect Thyroid Nodule Selection for Fine-Needle Aspiration Biopsy after Ultrasound Evaluation

Background and Objectives: This study was to evaluate whether high body mass index (BMI) or thyroid stimulating hormone (TSH) level would affect selecting thyroid nodule for fine-needle aspiration biopsy (FNA) after ultrasound (US) evaluation. Materials and Methods: A total of 3155 thyroid nodules (2159 benign and 996 malignant nodules) were included. Four grades of BMI and three levels of TSH were applied for grouping. US features of the thyroid nodules were divided into ‘probably benign’ and ‘suspicious for malignancy’ categories. Patients were grouped according to gender and univariate and multivariate logistic regression analysis were used to find the association between variables and malignancy. Results: TSH levels were significantly higher in the malignant group (p＜0.001). The grades of BMI did not show difference between the malignant and benign groups (females, p=0.074 and males, p=0.157). Younger age and ‘suspicious for malignancy’ US category were independent risk factors for malignancy in both genders. In females, a high TSH level (odds ratio=1.010, p＜0.001) had significant association with malignancy. Except for younger age (odds ratio=0.998, p＜0.001), no variable in nodules with ‘probably benign’ US category was significantly associated with malignancy. Conclusion: High TSH levels were more frequent in thyroid malignancy group, but neither high BMI nor high TSH level give additional information for FNA selection after US.