Obesity without diabetes: the role of hormonal regulation

Aim.  Obese patients without diabetes present an interesting phenotype to explore protective mechanisms against type 2 diabetes (T2D) development. In our study we looked for specific hormonal features of obese patients without T2D. Materials and methods.  We included 6 groups of patients with different metabolic profiles ( n =212): controls with BMI<25 kg/m 2 , HbA 1c <6%, age <30 years; patients with 25≤BMI<30 kg/m 2  and HbA 1c <6%; patients with 25≤BMI<30 kg/m 2  and HbA 1c ≥6%; patients with BMI≥30 kg/m 2  and HbA 1c <6% (“+ Obesity - T2D”) – obese patients without T2D or prediabetes; patients with BMI≥30 kg/m 2  and newly-diagnosed T2D/prediabetes, HbA 1c ≥6%; patients with known history of T2D on glucose-lowering drugs with BMI≥30 kg/m 2 . Insulin, GLP-1, GIP were measured during glucose-tolerance test at 0, 30 and 120 minutes; insulin resistance (IR) was assessed by HOMA-IR. Results.  Waist circumference was bigger in patients with obesity despite their metabolic profile comparing to patients without obesity ( p <0.001). Waist-to-hip ratio was similar in patients with different metabolic status. According to IR “+ Obesity - T2D” group had intermediate position: IR was higher in that group comparing to people without obesity, but was less that in patients with obesity and HbA 1c ≥6% ( p <0.001). “+ Obesity - T2D” group had the most potent baseline insulin secretion, assessed by НОМА-%b and the highest postprandial secretion, measured by insulinogenic index among all patient groups with obesity ( p <0.001). There was no significant difference in GLP-1 secretion; GIP secretion was higher in patients with BMI≥30 kg/m 2  comparing to people with BMI<30 kg/m 2  ( p <0.01).