A Study to Assess the Relationship Between Hypothyroidism and Serum Calcium Among Population Attending a Tertiary Care Centre in Northern Part of West Bengal, India

Background: Hypothyroidism is a common endocrine disorder known to affect multiple metabolic processes, including calcium homeostasis. Alterations in thyroid hormone levels may influence serum calcium through effects on bone turnover, renal handling, and hormonal regulation. The aim and objective is to assess the association between hypothyroidism and serum calcium levels and to evaluate the correlation between thyroid function parameters and calcium metabolism. Material and Methods: This hospital-based case–control study included 120 individuals aged 15–45 years, comprising 60 hypothyroid cases and 60 healthy controls. Hypothyroidism was defined as serum TSH >10 mIU/ml or TSH 6–10 mIU/ml with reduced fT3 and/or fT4 levels. Serum calcium was estimated using the Arsenazo III method. Data were analyzed using IBM SPSS Statistics and GraphPad Prism. Statistical tests included unpaired t-test, paired t-test, and Chi-square test, with p <0.05 considered significant. Results: The mean serum calcium level was significantly lower in hypothyroid patients (8.12 ± 0.64 mg/dL) compared to controls (9.26 ± 0.58 mg/dL) (p <0.001). Females showed slightly lower calcium levels than males, though not statistically significant (p = 0.627). A significant inverse relationship was observed between TSH levels and serum calcium (p = 0.031). Most patients (63.3%) had TSH >10 mIU/ml. Conclusion: Hypothyroidism is significantly associated with reduced serum calcium levels, with severity of thyroid dysfunction correlating with degree of hypocalcemia. Routine monitoring of calcium may aid in early detection and management of metabolic complications.

Keywords: Hypothyroidism, Serum Calcium, TSH, fT3, fT4, Hypocalcemia, Thyroid Dysfunction, Arsenazo III Method, Case–control Study.