Thyroid autoimmunity, depression and anxiety; are there any connections? An epidemiological study of a large population

Objective: The aim of the study was to examine the relationship between antithyroid antibodies, depression, and anxiety in a large population. Methods: In a population of 30,175 individuals aged 40-84 years, thyroid-stimulating hormone (TSH) was assessed in all women and in 50% of the men. Thyroid peroxidase autoantibodies (TPOAb) were measured in almost all samples with TSH >= 4.0 mU/L (n = 1700) and in randomly selected samples without thyroid disease or biochemical dysfunction (n = 745). The levels of anxiety and depression were screened using the Hospital Anxiety and Depression Scale (HADS). Relations were investigated with multiple logistic regression analyses. Results: In individuals with normal TSH and without known thyroid disorder, the prevalence of TPOAb was 14.2% in women and 4.3% in men. The prevalence of TPOAb in participants with biochemical thyroid dysfunction was 59.0% in women and 38.9% in men. No associations were found between thyroid autoimmunity and depression or anxiety, neither crude nor adjusted for age, gender, TSH, and thyroxine (T-4). Conclusion: Thyroid autoimmunity is a common disorder in the population, mainly affecting females. In a population-based study, no associations were found between antithyroid antibodies and depression or anxiety. (c) 2005 Elsevier Inc. All rights reserved.