Factors Associated with the Occurrence of Thyroid Nodules in Severely Obese Patients: A Case-Control Study

BACKGROUND: The association of obesity with the occurrence of thyroid nodules and thyroid cancer has been demonstrated. However, there is limited knowledge on the risk factors of thyroid nodules in in severely obese patients. The aim was to evaluate the occurrence of thyroid nodules in severely obese and nonobese patients and determine the factors associated considering sociodemographic, lifestyle, and biochemical variables. METHODS: This is a case-control study of 134 adults which 67 nonobese, control group, and 67 severely obese (BMI ≥ 35 kg/m2), case group. All participants underwent thyroid ultrasound. RESULTS: The occurrence of thyroid nodules in a control group was 13.4% (n = 9), while in a case group was 29.9%, n = 20), difference statistically significant (p = 0.017). Factors associated with the occurrence of thyroid nodules in severely obese patients were lower mean age (p = 0.022); higher economic class (p = 0.010); nonconsumption of alcohol (p = 0.017); higher fasting glycemia (p = 0.009), fasting insulin (p = 0.001), homeostatic model assessment of insulin resistance [HOMA-IR] (p = 0.045), and triglyceride (p = 0.009) mean values; and lower vitamin D(3) (p = 0.045) and high-density lipoprotein cholesterol (p = 0.041) mean values. CONCLUSIONS: Occurrence of thyroid nodules in severely obese patients was higher than nonobese. Lower age at diagnosis, higher economic level, nonconsumption of alcohol, hyperinsulinemia, higher HOMA-IR scores, and lower vitamin D(3) levels were factors associated with the occurrence of thyroid nodules in severely obese patients.