Effect of Vitamin D Status on Thyroid Dysfunction in Patients with COVID-19 |Biomedgrid

Aim/objective: Our study aimed to explore thyroid function in covid-19 patients and its correlation with vitamin D deficiency. Background: Several studies have found that abnormal thyroid function was standard in patients with COVID-9 and that thyroid stimulating hormone (TSH) suppression was associated with higher levels of markers of inflammation. On the other hand, there is evidence that vitamin D may modulate the secretion of TSH. Methods: Thyroid function was assessed in 195 unvaccinated COVID-19 patients (the target group) who presented with complaints suggesting disease of the thyroid gland by measuring serum free thyroxine (FT4), TSH, and anti-thyroid peroxidase antibody (TPOAb), and by cervical ultrasonography; the results were corresponding to subacute thyroiditis (SAT). Vitamin D status was determined at the initial presentation by measuring serum D (25-OH) levels. The target group was divided into three subgroups: I subgroup 58 patients with severe vitamin D deficiency (<12.5 ng/ml), II subgroup: 65 patients with moderate vitamin D deficiency (12.5-20 ng/ml), and III subgroup: 72 patients with vitamin D insufficiency (20-30 ng/ml). In addition, serum C-reactive protein (CRP) was measured in all the patients. The control group included 15 healthy individuals. After one month of treatment with corticosteroids, all the patients recovered from the symptoms of SAT. Results and Conclusions: In all three subgroups, the mean plasma TSH concentrations and FT4 concentrations were lower in COVID-19 patients compared to controls. Significant positive correlations were recorded between serum 25(OH)D and TSH, and negative correlations - between serum 25(OH)D and TF4 in the I and II subgroups. TPO-Ab was increased significantly in all three subgroups compared to controls, with a significant negative correlation with serum 25(OH)D in the I and II subgroups. Our study confirmed that low vitamin D levels could be associated with an increased risk of developing SAT in COVId-19 patients. However, it did not find a relationship between vitamin D deficiency and the severity of Covid-19 related thyrotoxicosis, nor it revealed that the severity of vitamin D deficiency affects the outcome of SAT in COVId-19 patients.