The association between the skeletal muscle state, lipid metabolism disorders and the development of insulin resistance in children with type 1 diabetes mellitus

The aim of the study. To establish a possible association between the skeletal muscles state, changes in lipid metabolism and the development of insulin resistance in children with type I diabetes mellitus. Materials and methods. 98 children with type 1 diabetes, aged from 11 to 17 years, were examined. Children were divided into 3 groups depending on the state of skeletal muscles: the first group – 22 children without disorders of the muscular system; the second group – 42 children with dynapenia; the third group – 34 patients with diabetic myopathy. The control group – 30 conditionally healthy children. The groups were representative by age, sex, and body mass index. Children were subjected to examinations of skeletal muscle mass and fat mass, followed by calculation of the skeletal muscle index and body fat percentage, sonomyography of the anterior group of thigh muscles with their thickness determination, measurements of the degree and coefficient of muscle hypotrophy, fasting blood glucose level, serum cholesterol, triglycerides and triglyceride-glucose (TyG) index. Insulin resistance was diagnosed when the TyG index was higher than 4.33 c. u. Results. It was found that the development of diabetic myopathy, in addition to a decrease in muscle mass, was characterized by a redistribution of the body component composition due an increase in the fat mass proportion. These changes were accompanied by a disturbance of lipid metabolism in the form of increase in serum cholesterol level, triglycerides and TyG index, which was 4.33 c. u. higher in 32.4 % of children with diabetic myopathy, and in 9.5 % of children with dynapenia, while among patients with normal state of the muscular system, the TyG index exceeded the threshold value in no case. Comparison of clinical and laboratory indicators depending on the TyG index level found an increase in the fat mass proportion, a violation of glycemic control, an increase in the daily dose of insulin, appearance of combined hyperlipidemia and the dawn phenomenon in children with an indicator that was higher than 4.33 c. u. All these were indicative of the insulin resistance development. Conclusions. Skeletal muscle dysfunction in children with type 1 diabetes is a causal risk factor for the development of insulin resistance, a sensitive marker of which is the TyG index. The simplicity of calculating this indicator allows it to be used in daily clinical practice.