Investigation of Eating Behaviors in Euthyroid Patients With Hashimoto's Thyroiditis.

Background Hashimoto's thyroiditis (HT) is an organ-specific autoimmune disorder. While eating disorders have been associated with other autoimmune diseases, no studies have explored this relationship in patients with HT to date. This study aimed to evaluate eating behaviors in euthyroid patients with HT. Materials and methods This case-control, cross-sectional study included a total of 107 patients diagnosed with HT, aged 18-45 years, as well as 54 healthy volunteers. Thyroid function tests, anti-thyroid peroxidase (TPO), and anti-antithyroglobulin (Tg) antibodies were measured in all participants. The Three-Factor Eating Questionnaire (TFEQ), the Night Eating Questionnaire (NEQ), and the International Physical Activity Questionnaire (IPAQ) were used to assess eating disorders and physical activity levels. Results Compared to the healthy control group, patients with HT, especially those receiving levothyroxine (LT4), had significantly higher scores on the TFEQ and NEQ. A positive correlation was detected between TFEQ and NEQ scores and anti-TPO and anti-Tg levels, LT4 treatment duration, and LT4 dose. However, there were no significant differences between the groups in terms of the IPAQ scores. A negative correlation was found between TFEQ scores and serum triiodothyronine (sT3). In patients with HT, thyroid-stimulating hormone (TSH) levels were within the higher-normal range, while sT3 levels were lower-normal compared to controls. Conclusion There is a spectrum of eating disorders among patients with HT. The underlying cause of these disorders remains unclear and may be associated with thyroid antibodies and/or hormonal status. In LT4 replacement therapy, efforts should be made to mimic true physiology as closely as possible. In the follow-up of patients with HT, while TSH is within lower-normal limits, sT3 levels may be observed to be in a higher-normal range. In selected cases, a combination of T4/T3 therapy or T3 extract may be recommended. Close monitoring of patients with HT is essential, particularly for potential eating disorder-related complications, such as obesity.