The Relationship between Iodine and Selenium Levels with Anxiety and Depression in Patients with Euthyroid Nodular Goiter.

Objectives: Selenium and iodine are essential microelements for normal body functions. These two elements play important roles in thyroid metabolism. The potential relationship between thyroid diseases and mental disorders have been demonstrated. We aimed to investigate the relationship between selenium and iodine levels with anxiety and depression in patients with euthyroid nodular goiter (ENG).

Methods: In this cross-sectional study, we enrolled 102 consecutive patients with ENG who attended the endocrine outpatient clinic between January 2018 and June 2018. We noted the patient's demographics, thyroid ultrasound imaging, thyroid hormones, and urinary iodine concentration (UIC) results. We also obtained venous blood samples for serum selenium measurement. The same psychiatrist completed the Beck Anxiety Inventory (BAI) and Hamilton Depression Rating Scale (HDRS) for all participants. The study population was dichotomized according to the median values of selenium levels and UIC.

Results: BAI and HDRS scores were significantly higher in the low selenium group than the high selenium group ( 0.032 and 0.042, respectively). BAI scores were significantly higher in the low UIC group than the high UIC group ( 0.007).

Conclusions: Low selenium and UIC levels may contribute to the development of anxiety and depression, independent of thyroid functions, in patients with ENG. In these patients, selenium and iodine replacement may be useful for the prevention of anxiety and depression, especially in deficient regions.