VITAMIN D DEFICIENCY AS A RISK FACTOR FOR ANXIETY-DEPRESSIVE DISORDERS IN PATIENTS WITH HYPOTHYROIDISM ON THE BACKGROUND OF AUTOIMMUNE THYROIDITIS

Abstract

Today, Ukraine has a particularly high level of depression compared to other countries, as well as an increase in the number of cases of both depressive disorders and vitamin D-deficient states. Residents of frontline zones are a particularly affected cohort of the population. Psychogenic factors can be a trigger for the development of many diseases, including thyroid pathology, especially in the presence of insufficient vitamin D. There is a certain number of studies, the results of which demonstrate the connection between vitamin D deficiency and more clinically pronounced depressive disorders, which are aggravated precisely against the background of thyroid dysfunction. Despite the fact that the connection between hypothyroidism and depression has been established for a long time, there are still no clear ideas about the severity of depression in hypothyroidism.

Goal. To determine the relationship between vitamin D levels and indicators of mental disorders in patients with subclinical hypothyroidism on the background of autoimmune thyroiditis, who live in frontline zones.

Materials and methods. 26 women aged 24-38 years, who lived in Kharkiv during the study period and suffered from subclinical hypothyroidism on the background of autoimmune thyroiditis, were examined. The content of vitamin D in the blood was determined by the enzyme-linked immunosorbent assay (ELISA) using the 25-OH Vitamin D (total) ELISA kit (Germany). In order to assess thyroid status, the levels of free thyroxine (T4b), thyroid-stimulating hormone (TSH) in the blood serum were determined by the ELISA using test kits according to the attached protocols for determination. The concentration of hormones was expressed in mU/L (TSH) and pmol/L (for T4b). The level of anti-thyroglobulin antibodies (ATTG), as an indicator of the humoral antithyroid immunity state, was determined by the ELISA (AIF-C-01S; the laboratory norm was considered to be the level of ATTG <64 U/mL). Symptoms of psychological disorders were assessed using validated self-assessment tools, such as the Hamilton Depression Scale (HAM-D – 17), as well as the Hamilton Anxiety Scale (HAM-A). Statistical processing of the results was carried out using the STATISTICA 10.0. To calculate the relationship between vitamin D levels and depression, simple linear and multiple regression methods, as well as MC Excel and ROC analysis programs were used.

Results. The thyroid status indicators of the examined subjects showed the presence of subclinical hypothyroidism. A parallelism was established between the progression of the degree of depression and TSH levels (p < 0.001). A direct relationship was observed between the TSH level and indicators of depression (r_s = 0.83; p < 0.01). Analysis of the relationship between vitamin D levels and the degree of progression of depression according to the MADRS revealed a parallelism between the degree of decrease in the vitamin level in the blood and the severity of depression. A decrease in vitamin D in the blood is associated with a greater severity of depression, as evidenced by a negative or inverse correlation (r_s = -0.94; p < 0.01). The ROC analysis of TSH levels in relation to free thyroxine T4b established a moderate diagnostic value of the indicators (AUC = 0.762; 95% CI 0.62–0.87, p = 0.025) and allowed, with a sensitivity of 98.6% and a specificity of 67.3%, to establish the point of distribution of values, where the intensity of the depressive syndrome is observed.

Conclusions. In conditions of martial law, the majority of patients with subclinical hypothyroidism suffer from depressive disorders. The study established a negative correlation between the level of vitamin D supply and the degree of severity of the depressive syndrome. Logistic analysis of the odds ratio showed that both vitamin D insufficiency or deficiency and concomitant subclinical hypothyroidism are significant predictors of the adverse course of the depressive syndrome against the background of stressful factors of life in the front-line zone.