Role of reduced thyroid hormone status on bone mineral metabolism

Abstract

Background: The most common endocrine disorder is hypothyroidism which accounts to 11%. Thyroid hormones have a wide array of functions such as physiological growth and development of skeletal system, maintenance of basal metabolic rate and regulation of various metabolisms, including mineral metabolism. Nowadays due to its direct action on bone turn over, thyroid hormones are considered to have an important role on bone mineral metabolism. Thyroid disorders are important cause for secondary osteoporosis. So the present study was done to know the levels of bone minerals, calcium and phosphorus in hypothyroidism and its relation with thyroid hormone levels. Methods: A case-control study was conducted on 30 hypothyroid patients and 30 euthyroid healthy controls in the age group of 20-60 years. Blood samples were collected from all the study population. Serum total triiodothyronine, total thyroxine and TSH by Enzyme-Linked Immunosorbent Assay, Serum calcium by Arsenazo III method, phosphorous by ammonium molybdate method were estimated. Results: Serum calcium levels in cases was found to significantly reduced when compared to controls (p<0.001). Serum phosphorous levels also showed considerable elevation in cases when compared to controls (p<0.001). There was a significant negative correlation between TSH and serum calcium in cases. Conclusion: The present study indicated the important role of reduced thyroid hormone status on bone mineral metabolism. This study concludes that serum calcium was significantly reduced and phosphorus levels were significantly increased in hypothyroid patients when compared to euthyroid control subjects. So frequent monitoring of serum calcium and phosphorus in hypothyroid patients would reduce the burden of bone pathologies.