Role Of 25-Hydroxyvitamin D And Vitamin D Receptor In Hyperthyroidism: A Case-Control Study In A South Indian Population

Background:Hyperthyroidism is characterized by the thyroid gland's excessive production and release of thyroid hormones into the bloodstream. The global prevalence ranges between 0.2% and 2.5% in iodine-sufficient regions. Vitamin D has been implicated in the regulation of thyroid-related autoimmune and neoplastic disorders, primarily through its interaction with the vitamin D receptor (VDR). Notably, both vitamin D and thyroid hormones exert their effects via receptors belonging to the steroid hormone receptor family. Aim:This study aims to investigate the role of the Vitamin D receptor (VDR) and 25-hydroxyvitamin D (25(OH)D) levels in the pathophysiology of hyperthyroidism by exploring their association in a South Indian population through a case-control design. Methods: An observational study was conducted using a cross-sectional design involving 188 participants (80hyperthyroid cases and 108 healthy controls) aged 18-70, matched for age and sex. Participants with a history of thyroidectomy, pregnant women, and individuals under 18 years were excluded. Blood samples were collected from all participants for necessary investigations. Thyroid profiles, thyroid antibodies, and Vitamin D levels were assessed using a fully automated chemiluminescent hormone analyzer, and VDR levels were measured using a commercially available human ELISA kit. All biochemical parameters were analyzed using a fully automated biochemistry analyzer. A p-value of <0.05 was considered statistically significant. Results: The VDR levels among cases and controls were 0.49 ± 0.19 and 2.51 ± 0.67, and 25(OH) D3 levels were 14.58 ± 6.03 & 22.09 ± 9.75, respectively. A statistically significant difference in VDR and 25(OH) D3 levels was found between the case and control groups (p < 0.05). Conclusions: Our findings reveal a notable relationship between the vitamin D receptor (VDR), 25(OH)D, and the levels of total T3 and total T4 in individuals with hyperthyroidism,suggesting that VDR may serve as a diagnostic marker for hyperthyroidism. Additional studies are needed to clarify the role of VDR in preventing and treating thyroid disorders, highlighting the need for more comprehensive research on VDR.