Relationship between growth hormone/insulin-like growth factor-1 axis integrity and voluntary weight loss after gastric banding surgery for severe obesity.
BACKGROUND
The aim of this observational study was to determine, in a retrospective analysis, whether growth hormone (GH) and insulin-like growth factor-1 (IGF-1) at baseline or changes in the GH/IGF-1 axis after laparoscopic adjustable gastric banding (LAGB) is associated with weight loss and body composition changes in severely obese nondiabetic patients.


METHODS
Weight loss (expressed as percent excess weight loss [EWL%]), anthropometry, body composition by bioelectrical impedance analysis (BIA), serum IGF-1, and GH peak after GH-releasing hormone (GHRH) plus arginine (ARG) test were measured and expressed as standard deviation scores (SDS) of reference values in 104 women and 36 men, age (mean +/- SD) 34 +/- 11 and 30.2 +/- 11 years, and BMI 44 +/- 5.7 and 39 +/- 3.2, respectively, before and 6 months after LAGB.


RESULTS
After LAGB, 25% of women and 22.5% of men had GH deficiency, while 30.8% of women and 33.3% of men had IGF-1 deficiency or insufficiency. The median EWL was 36.8% in women and 40.0% in men. In both genders, percent decrease of waist circumference, EWL, and fat mass (FM) and percent increase of fat-free mass (FFM) was greater in patients with normal GH secretion and IGF-1 levels. The GH peak after GHRH + ARG, IGF-1 levels, and IGF-1 SDS were inversely correlated with EWL% (r = -0.50, r = -0.53, and r = -0.42, respectively; p < 0.0001) and percent FM (r = -0.41, r = -0.36, and r = -0.35, respectively; p < 0.0001). In stepwise linear regression analysis, the GH peak after GHRH + ARG was the major determinant of EWL% (p < 0.0001) and FM (p = 0.001).


CONCLUSIONS
The efficacy of LAGB was greater in the patients with a normal GH response to GHRH + ARG and with normal IGF-1 levels. The percent of FM, FFM, and EWL were significantly correlated with the GH response to GHRH + ARG and with IGF-1 levels.
Savastano
Silvia
S
Division of Endocrinology, Department of Molecular and Clinical Endocrinology and Oncology, University of Naples Federico II, via S Pansini 5, 80131 Naples, Italy. sisavast@unina.it
Angrisani
Luigi
L
Di Somma
Carolina
C
Rota
Francesca
F
Savanelli
Maria Cristina
MC
Cascella
Teresa
T
Orio
Francesco
F
Lombardi
Gaetano
G
Colao
Annamaria
A
D000273:Adipose Tissue / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D001823:Body Composition / Q000502:physiology*; D005260:Female; D015391:Gastroplasty; D019382:Human Growth Hormone / Q000097:blood* / Q000172:deficiency; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000172:deficiency / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000503:physiopathology / Q000601:surgery; D012189:Retrospective Studies; D015431:Weight Loss / Q000502:physiology*; D055815:Young Adult
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I