Serum Insulin-Like Growth Factor-1 Concentrations Are Reduced in Severely Obese Women and Raise After Weight Loss Induced by Laparoscopic Adjustable Gastric Banding

Background Obesity is associated with abnormalities of the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis. The role of serum IGF-1 measurement for recognition of hypothalamic–pituitary diseases in obesity is still a matter of debate. Methods This study evaluated the serum levels of IGF-1 in a population of severely obese women before and after long-term weight loss obtained by laparoscopic adjustable gastric banding (LAGB). Eighty obese women with body mass index (BMI) of more than 34 kg/m 2 and 80 unrelated age-matched lean controls were enrolled. IGF-1 serum levels were measured together with BMI, liver volume, and intra-abdominal fat thickness assessed by ultrasound. Evaluation was repeated 2 years after LAGB. Results Our results showed that mean IGF-1 levels in obese subjects before LAGB were significantly lower ( p < 0.001) than that observed in age-matched controls. Age and BMI were independent predictors of serum IGF-1 values, overall accounting for 39 % of IGF-1 variability. The mean IGF-1 concentration significantly increased 2 years after LAGB. BMI reduction was independently associated with IGF-1 increase ( r = −0.29, p < 0.001). For each point of BMI reduction, the mean increase of serum IGF-1 was 4.39 ng/mL. Conclusions (1) Severely obese women have low IGF-1 serum levels with respect to normal weight age-matched controls; (2) the extent of IGF-1 deficiency is proportional to increased BMI; (3) after LAGB a spontaneous raise of serum IGF-1 occurs, proportional to the extent of weight reduction; and (4) serum IGF-1 in severely obese subjects may have a limited value for detection of hypothalamic–pituitary diseases.