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.
Endocrinology Unit, University Hospital of Pisa, Pisa, Italy.
Giulia
G
Galli
Aldo
A
Pinchera
Paolo
P
Piaggi
Paola
P
Fierabracci
Monica
M
Giannetti
Giorgia
G
Querci
Giovanni
G
Scartabelli
Luca
L
Manetti
Giovanni
G
Ceccarini
Silvia
S
Martinelli
Claudio
C
Di Salvo
Marco
M
Anselmino
Fausto
F
Bogazzi
Alberto
A
Landi
Paolo
P
Vitti
Margherita
M
Maffei
Ferruccio
F
Santini
D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D015391:Gastroplasty / Q000379:methods*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000172:deficiency / Q000378:metabolism*; D050152:Intra-Abdominal Fat / Q000000981:diagnostic imaging / Q000473:pathology*; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology*; D009767:Obesity, Morbid / Q000097:blood* / Q000000981:diagnostic imaging / Q000601:surgery; D017697:Premenopause; D011446:Prospective Studies; D014463:Ultrasonography; D015431:Weight Loss
D007334:Insulin-Like Growth Factor I