The Effect of Thyriod medications on blood calcium levels, Vitamin D, and Thyroid Hormone Levels: A Cross-Sectional Comparative Study

Abstract

Our study  evaluate and compare serum calcium, vitamin D, and thyroid hormone (TSH, free T3, free T4) levels among patients with hypothyroidism, patients with hyperthyroidism, and healthy controls, and to examine whether the type or dosage of thyroid medication correlates with serum calcium concentration. A comparative design was employed, involving 69 participants divided into healthy controls, hyperthyroid, and hypothyroid groups. Serum levels of calcium, Vitamin D, and thyroid hormones (TSH, T3, T4) were measured and analyzed using one-way ANOVA. The results indicated no statistically significant differences in mean serum calcium levels among the groups (P = 0.80), nor did specific thyroid medications or their dosages significantly impact serum calcium concentrations (P = 0.47). However, a significant reduction in serum Vitamin D levels was observed in patients with thyroid disorders, particularly in the hypothyroid group (P < 0.05). Thyroid hormone levels (TSH, T3, T4) showed expected significant differences across groups, confirming the physiological impact of the disorders and treatment effectiveness. We can conclude that while thyroid medications effectively modulate thyroid hormone levels, their direct effect on serum calcium appears minimal due to robust physiological compensatory mechanisms. The findings highlight the importance of monitoring Vitamin D status in thyroid patients due to prevalent deficiency, and considering potential drug interactions, especially between calcium supplements and levothyroxine absorption.