Plasma insulin, growth hormone, cortisol, and central obesity among young Chinese type 2 diabetic patients

OBJECTIVE- To examine the relationships between central obesity, insulin re sistance index, plasma insulin, growth hormone (GH), and cortisol concentra tions in 90 young Chinese type 2 diabetic patients (aged 33 +/- 5 years) an d 104 age- and sex-matched control subjects (aged 32 +/- 9 years). RESEARCH DESIGN AND METHODS - Young Chinese diabetic patients (aged <40 yea rs) were recruited from the Prince of Wales Hospital. Blood pressure; heigh t, weight, and waist and hip circumferences were determined. Venous blood w as sampled for measurements of fasting plasma glucose, HbA(1c) lipids, crea tinine, insulin, GH, and cortisol. A 24-h urine was assayed for urinary alb umin excretion (UAE). General and central obesity was represented by BMI an d waist circumference, respectively. Insulin resistance index was estimated as a product of fasting plasma insulin and glucose concentrations. RESULTS - Compared with control subjects, diabetic patients were more obese , hyperglycemic, and had worse lipid profile, higher blood pressures, UAE, insulin resistance index, plasma insulin, and cortisol concentrations (all P < 0.001) but lower GH concentrations (P < 0.05). When analyzed as a whole group (n = 194), increasing quartiles of waist circumference were associat ed with increasing trends of insulin resistance index, plasma insulin, and cortisol concentrations (all P < 0.01) but a decreasing trend of plasma GH concentration (P < 0.05). Using stepwise multiple regression analysis, wais t circumference was only associated with sex variable (being higher in men) in the control subjects. In the diabetic group, 51% of waist circumference was independently related to male sex and increased plasma insulin and cor tisol concentrations as well as reduced plasma GH levels. CONCLUSIONS- In young Chinese type 2 diabetic patients, hyperinsulinemia, h ypercortisolemia, and reduced plasma GH levels were closely associated with central obesity Based on these findings, we postulate that maladaptive hor monal responses to rapid changes in lifestyle may have led to obesity and t ype 2 diabetes in these young patients. Alternatively, lifestyle-related ob esity may have given rise to these hormonal changes, More studies are requi red to delineate the nature of these relationships.