Leptin Resistance as a Risk Marker of Type 2 Diabetes Mellitus in Obese Patients

Abstract

The purpose of the study was to investigate the influence of leptin resistance on the formation of the risk of type 2 diabetes mellitus in obese patients. We monitored 50 obese patients who consulted an endocrinologist and a gastroenterologist-nutritionist during 2021-2022. The diagnosis of obesity was made on the basis of bioimpedance examination, as well as by calculating the body mass index. The article describes and analyzes the level of leptin and leptin resistance as a marker of the risk of type 2 diabetes mellitus in obese patients. To establish the diagnosis of obesity, all patients underwent a bioimpedance examination, and the body mass index was also calculated. Obesity was diagnosed when the body fat content of women was more than 40%, men – more than 28%, and body mass index – more than 30 kg/m2. To identify the syndrome of insulin resistance, the index of insulin resistance was calculated according to the formula: HOMA-IR = fasting insulin (μIU/ml) x fasting glucose (mmol/l) / 22.5. Values exceeding 2.0 were considered insulin resistance. Leptin resistance was diagnosed by determining the presence of the leptin receptor gene and leptin level in blood serum. Leptin resistance was considered to be values of leptin indicators for men more than 5.6 ng/ml, for women – more than 11.1 ng/ml. The level of leptin in blood serum in the group of healthy individuals was within the range of 6.36± 2.09 ng/ml in women and 2.96 ± 1.84 ng/ml in men. On the other hand, in obese patients, the serum leptin concentration was 51.49 ± 8.33 ng/ml and 29.71 ± 6.93 ng/ml, respectively. Also, according to the results of the study, a significantly higher level of insulin resistance was observed in all obese patients compared to the control group. These values were at the level of 6.64 ± 2.81 and 7.11 ± 3.52, respectively. Analyzing the results of the study, a reliable relationship between the level of leptin and the severity of obesity was found in all patients. A clear relationship between leptin level and the degree of insulin resistance was also determined. A correlation between the level of leptin and HOMA-IR (r=0.70333; p=0.052) was established, as well as a correlation between fat content, body mass index, leptin level and HOMA-IR (r=0.86187, р=0.0086; r=0.93595, р=0.009; r=0.78098, р=0.007). The detected changes indicate a possible role of leptin and leptin resistance in the pathogenesis of type 2 diabetes mellitus and indicate that the level of leptin can be used as a predictor of the risk of developing type 2 diabetes mellitus in obese patients. An increase in leptin level in blood serum is observed in obese patients. The level of leptin affects the degree of insulin resistance and can be an additional marker of the risk of type 2 diabetes mellitus in obese patients.