The effect of vitamin D intake on AntiTPO levels in hypothyroid and euthyroid patients with anti-TPO positive: an interventional study

Abstract

Many studies have shown that low vitamin D levels contribute to the development of autoimmune thyroid diseases (AITDs). This study was designed to investigate vitamin D levels and its relationship with anti-thyroid peroxidase (anti-TPO) antibodies in patients with autoimmune hypothyroidism. Methods: Methods: In this clinical trial study, 128 Anti-TPO positive patients (mean age 41.48 ± 9.58 years) were introduced by the laboratory and divided into hypothyroid and euthyroid based on TSH and FreeT4 levels. Then, the serum vitamin D level was checked from the patients of each of the hypothyroid and euthyroid groups in the same time period, and the level of vitamin D in the volunteers' serum was measured, and the volunteers of each group were divided into two groups with deficiency in vitamin D and inadequate levels of vitamin D were distributed. Those whose serum vitamin D level was less than 10 ng/ml were considered as deficient group and 50 thousand units of vitamin D3 tablets were prescribed every week for 8 weeks. After 8 weeks, a supplement of 800 to 1000 units of vitamin D was prescribed daily. Those whose serum level of vitamin D is between 10 and 20 ng/ml are considered as insufficient group and 800 to 1000 units of vitamin D tablets were prescribed daily for 3 months. After 3 months of evaluation, the patients were subjected to final evaluation and the serum levels of vitamin D and Anti-TPO were measured and the relationship between vitamin D and Anti-TPO levels was measured after 6 months from the start of the intervention. Results: Three months after receiving vitamin D, the mean of AntiTPO decreased by 152.73 ± 17.34 units in the euthyroid group and 163.98 ± 32.81 units in the hypothyroid group, which was statistically significant (p< 0.001 and p = 0.006, respectively). The average AntiTPO three months after the intervention of vitamin D intake in the hypothyroid group was 162.20 ± 35.02 units higher than this value in the euthyroid group, which difference was statistically significant (p = 0.006). After the intervention, the average vitamin D in the euthyroid group increased by 12.27 ± 1.23 units and in the hypothyroid group by 9.85 ± 2.32 units, which was statistically significant (p < 0.001 and p= 0.001, respectively). The average vitamin D level three months after the intervention in the euthyroid group was 6.35 ± 2.62 units higher than that in the hypothyroid group, which difference was statistically significant (p = 0.017). There was also an inverse relationship between AntiTPO and vitamin D over the study period. However, this relationship was not statistically significant (p < 0.05).