Multivariable Analysis of Serum 3,5,3'-L-Triiodothyronine Concentration in Patients of Diabetes Mellitus by Blood Glucose Level and Body Weight

Summary

Serum thyroid hormone concentrations, 1-thyroxine (T₄), free T₄ and 3,5,3'-1-triiodothyronine (T₃) were measured in 213 patients of diabetes and analyzed their correlation with metabolic parameters, hyperglycemia and body weight. Haemoglobin A₁ (HbA₁) was used as an index of hyperglycemia. Body weight was expressed by relative body weight (body weight/standard weight). Among the thyroid hormones, only T₃ had significant Correlation with HbA₁ and body weight (r=-0.476, P % 0.01 and r=0.369, P < 0.01, respectively). Multivariable analysis of serum T₃ by HbA₁ and relative body weight gave the following regression equation. Serum T₃ (ng/dl)=108 + 0.362 × relative body weight (%)-3.88 × HbA₁ (%). Though relative body weight had inverse correlation with HbA₁, the contribution of the two metabolic parameters to the serum T₃ was independent from each other. Our results confirm the previous reports that low T₃ in diabetes correlates with severity of hyperglycemia and we report for the first time that serum T₃ of diabetic patients has positive correlation with body weight, probably due to still available carbohydrate in spite of disturbances in the metabolism.

Key words

3,5,3'-L-Triiodothyronine (T₃) - Low T₃ Syndrome - Hyperglycemia - Body Weight - Diabetes Mellitus