Disorders of thyroid hormones in non-insulin-dependent diabetes mellitus

ABSTRACT

INTRODUCTION: In a previous study of patients with non-insulin-dependent diabetes mellitus (NIDDM) of less than 5 years' duration at the HCQ "Hermanos Ameijeiras", Cuba, we found abnormal values of T3 at iniitial evaluation. It was proved that the cause was an increase in the activity of the enzyme catalysing the process of peripheral deiodination of T4 to T3. OBJECTIVE: To examine these variables in a larger sample. SUBJECTS AND METHODS: One hundred and forty patients with NIDDM of 1-25 years' duration being treated by diet, and/or oral hypoglycaemic agents, were studied T3, T4, and insulin were measured by radio-immunoassay; glucose, by glucose-oxidase; cholesterol, triglycerides and HDL-cholestrol by the Trinder method; LDL and VLDL by the Ellefson formula; glycosylated haemoglobin by ion exchange chromatography, and microalbuminuria by an immuno-colorimetric semiquantitative method. The sample was divided into 5 groups 1-2 years, 3-4 years, 5-6 years, 7-15 years, and more than 15 years' duration of diabetes mellitus. RESULTS: The results confirmed the previous findings that there was a marked increase in T3 (4.87, 4.49, 3.1, 2.8, 2.9 mmol/l, respectively) in the time of evolution but diminishing progressively as the time of evolution increases and normalizing in the 5-6 year group. There were no notable differences in T4 in the 5 groups of healthy controls (102, 113, 96, 94, 99 mmol/l). The blood glucose levels were higher than in the healthy population but a point of inflection was noted in the 5th -6th year of evolution (8.6, 8.2. 7.02, 8.4, 8.3 mmol/l). The insulin values were noted to have a greater variation between 1-2 years and 3-4 years, supposedly a treatment effect as in the 1-2 year group. There were patients who had not started treatment but the insulin in the 3-4 year group decreased with the introduction of treatment (48.7, 17.9, 32.1, 36.6, 39.5 mU/ml). Glycosylated haemoglobin showed a point of inflection in the 5th-6th year (7.2, 6.3, 8.2, 7.9, 8.5 percent). Lipid metabolism indicators, cholesterol (4.7, 5.2, 5.6, 5.74, 5.5 mmol/l), triglyceride (1.34, 2.01, 1.33, 1.95, 1.65 mmol/l) and low density lipoprotein (2.99, 3.14, 3.97, 3.95, 3.63 mmol/l) progressively increased with time of evolution. Microalbuminuria behaved the same (25, 12.4, 14.5, 33.4, 27.3 mg/l), showing a higher value at 1-2 years and diminishing between 3 and 6 years but increasing thereafter.(Au)