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 > or = 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 (T4).

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.