INSULIN-LIKE GROWTH-FACTOR-I AND INSULIN-LIKE-GROWTH-FACTOR BINDING PROTEIN-1 IN A REPRESENTATIVE POPULATION OF TYPE-2 DIABETIC-PATIENTS INSWEDEN

Objective: To study the influence of type 2 diabetes on the insulin-li ke growth factor-I (IGF-I) and insulin-like growth factor binding prot ein-1 (IGFBP-1) serum levels in an area-based population of type 2 pat ients previously described. Results. The patients (n = 151) were elder ly (70.6 +/- 0.7 years of age) and moderately overweight (BMI 27.0 +/- 0.4 kg/m(2)). Most patients (83%) were treated with either diet alone or diet in combination with sulphonylurea. Metabolic control measured as HbAlc deteriorated with duration (p<0.001) and between groups trea ted with diet (HbAlc 5.8+/-0.6), sulphonylurea (7.5+/-0.2) and insulin (7.7+/-0.4). Mean levels of IGF-I were within reported normal range, but were lower in the insulin-treated as compared to the non-insulin-t reated patients. Levels of IGF-I decreased with diabetes duration and with increased blood glucose. There was a positive correlation between IGF-I and insulin levels and also an inverse correlation between IGF- I and IGFBP-1 levels. The IGFBP-1 levels were twofold higher than repo rted in non-diabetic individuals. In multiple stepwise correlation ana lysis, 37% of the variability in IGFBP-1 could be explained by BMI, IG F-I SD score, age, IGF-I, and fasting blood glucose. Conclusion: Our s tudy indicates that influence of type 2 diabetes on IGF-I bioavailabil ity in individual patients is modulated by insulin, body weight (presu mably reflecting insulin sensitivity) and metabolic control. Furthermo re, increased levels of IGFBP-1 are strongly associated with decreased b-cell function in type 2 diabetes mellitus.