Calcium and Magnesium Levels in Subclinical and Overt Hypothyroidism: A Cross-sectional Study

Abstract

Introduction: Hypothyroidism, one of the most common thyroid gland disorders, can cause electrolyte disturbances in the body. Hypothyroidism can alter mineral metabolism by changing the levels of serum calcium and magnesium. Therefore, it is essential to study any abnormalities in calcium and magnesium metabolism in patients with hypothyroidism. Aim: The aim of this study was to assess the levels of calcium and magnesium in patients with hypothyroidism and to study the correlation between Thyroid Stimulating Hormone (TSH), fT3, and fT4 with calcium and magnesium in subclinical and Overt Hypothyroidism (OH). Materials and Methods: This cross-sectional study was held from August 2019 to January 2020 in the Department of Biochemistry, BS Medical College, Bankura. A total of 150 subjects were included in the study, distributed equally among three groups: euthyroidism, subclinical hypothyroidism, and OH. Serum TSH, fT3, fT4, calcium, and magnesium levels were determined in the laboratory, and the data obtained were statistically analysed using ANOVA test and Pearson’s correlation test. Results: Out of a total of 150 subjects, 61 were female, among whom 23 had subclinical hypothyroidism and 21 had OH. There were significant differences in the mean levels of TSH, fT3, fT4, calcium, and magnesium between the SCH, OH, and euthyroid groups. The study showed that the mean serum calcium level was significantly lower in SCH and OH compared to euthyroids, while the level of serum magnesium was significantly increased in SCH and OH compared to euthyroid. There was a statistically significant negative correlation between TSH and serum calcium in both OH and SCH, while a statistically significant positive correlation was observed between TSH and serum magnesium levels in both groups. Conclusion: The present study revealed that serum magnesium levels were high while serum calcium levels were low in both subclinical hypothyroidism and OH when compared to euthyroid subjects. Additionally, calcium levels negatively correlated with TSH, while magnesium levels positively correlated with TSH levels.