Role of Gamma Glutamyl Transferase in the Diagnosis of Metabolic Syndrome in Patients with Hypothyroidism

Introduction: Hypothyroidism is the most prevalent thyroid disorder in India that affects one in ten adults. Gamma Glutamyl Transferase (GGT) is an ectopic enzyme associated with oxidative stress in various diseased conditions. Prior research suggests that increased levels of GGT are associated with Metabolic Syndrome (MetS) in hypothyroidism. Aim: To study the prevalence of MetS in patients with hypothyroidism and to correlate serum GGT levels with the components of MetS. Materials and Methods: The case-control study was conducted on 62 clinically diagnosed hypothyroidism patients (cases) and 63 clinically proven healthy subjects (controls). All these subjects were screened for metabolic syndrome based on the NCEP ATP III (National Cholesterol Education Programme Adult Treatment Panel III) guidelines. Waist circumference, blood pressure, serum Fasting Blood Sugar (FBS), Urea, Creatinine, T3, T4, Thyroid Stimulating Hormone (TSH), Total Cholesterol (TC), Triglycerides (TG), High Density Lipoprotein Cholesterol HDL-C), Low Density Lipoprotein Cholesterol (LDL-C) and GGT were measured. Data was expressed as mean +/- SD and analysed using Independent Student t-test. The p-value <0.05 was considered as statistically significant. Results: Waist circumference, Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), FBS, TC, Triglycerides TG, LDL-C, GGT and TSH were significantly increased in hypothyroid cases when compared to the controls. HDL-C was significantly decreased in hypothyroid cases. Significant positive correlation was observed between GGT and TSH (r=0.57, p=0.004) in hypothyroid cases with MetS. Significant inverse correlation was observed between GGT and HDL-C (r=-0.25, p=0.04 in hypothyroid cases. Conclusion: In this study, 38% of hypothyroid patients had MetS. Serum GGT is found to be elevated in hypothyroid cases and associated with components of MetS. Hence GGT can be used as an additional diagnostic marker to assess the MetS in hypothyroidism.