Evaluation of thyroid profile status in case of type-2 diabetes mellitus in North Indian population

Abstract

Diabetes mellitus (DM) is a group ofaetiologically different metabolic disorder characterized by hyperglycemia dueto inadequate insulin secretion or defect in insulin action or both. There isstrong correlation between DM and thyroid hormones. The aim of this study wasto find out the association between hypothyroidism and type 2 diabetes mellitusin north Indian patients to evaluate the hyperglycemic effect by correlatingfasting blood glucose (FBG), glycosylated hemoglobin (HbA1c) and thyroidprofile parameters. 50 type-2 DM patients and 50 controls were studied fortheir thyroid profile along with their fasting glucose levels and glycosylatedhemoglobin (HbA1c). Analysis was performed by comparing the values with age andmatched controls using student‘t’ test. Analysis showed that in type 2 diabetesmellitus patients and thyroid dysfunction prevalence rate in our study is high.Serum tri-idothyronine (T3) and tetra-idothyronine (T4) hormone concentrationswere low and Thyroid Stimulating Hormone (TSH) concentrations were high in Type2 DM when compared to controls. The T3 (p value <0.05), T4 and TSH (p value,<0.001) shows significant difference. FSG (p value, <0.05) also showsignificant correlations with thyroid profile parameters. Type 2 DiabetesMellitus patients are at risk for hypothyroidism and hence have to be followedup with serum TSH levels. There was significant and inverse relation of HbA1cwith thyroid hormone level whereas level of serum TSHwas seen to have significant and direct relation with HbA1c. Insulin ananabolic hormone metabolizes glucose enhances the level of freeT4 (FT4) whileit suppresses the level of T3 by inhibiting hepatic conversion of T4 to T3. Onthe other hand some of the oral hypoglycemic agents such as the phenylthioureasare known to suppress the level of FT4 and T4, while causing raised levels ofTSH.