Changes in bone mineral density, body composition and adiponectin levels in morbidly obese patients after bariatric surgery.
BACKGROUND
Gastric bypass surgery (GBP) is increasingly used as a treatment option in morbid obesity. Little is known about the effects of this surgery on bone mineral density (BMD) and the underlying mechanisms. To evaluate changes on BMD after GBP and its relation with changes in body composition and serum adiponectin, a longitudinal study in morbid obese subjects was conducted.


METHODS
Forty-two women (BMI 45.0 +/- 4.3 kg/m(2); 37.7 +/- 9.6 years) were studied before surgery and 6 and 12 months after GBP. Percentage of body fat (%BF), fat-free mass (FFM), and BMD were measured by dual-energy X-ray absorptiometry and serum adiponectin levels by RIA.


RESULTS
Twelve months after, GBP weight was decreased by 34.4 +/- 6.5% and excess weight loss was 68.2 +/- 12.8%. Significant reduction (p < 0.001) in total BMD (-3.0 +/- 2.1%), spine BMD (-7.4 +/- 6.8%) and hip BMD (-10.5 +/- 5.6%) were observed. Adiponectin concentration increased from 11.4 +/- 0.7 mg/L before surgery to 15.7 +/- 0.7 and 19.8 +/- 1.0 at the sixth and twelfth month after GBP, respectively (p < 0.001). Thirty-seven percent of the variation in total BMD could be explained by baseline weight, initial BMD, BF reduction, and adiponectin at the twelfth month (r (2) = 0.373; p < 0.001). Adiponectin at the twelfth month had a significant and positive correlation with the reduction of BMD, unrelated to baseline and variation in body composition parameters (adjusted correlation coefficient: r = 0.36).


CONCLUSIONS
GBP induces a significant BMD loss related with changes in body composition, although some metabolic mediators, such as adiponectin increase, may have an independent action on BMD which deserves further study.
Carrasco
Fernando
F
Department of Nutrition, Faculty of Medicine, University of Chile, Independencia 1027, Postal Code 838-0453, Santiago, Chile. fcarrasc@med.uchile.cl
Ruz
Manuel
M
Rojas
Pamela
P
Csendes
Attila
A
Rebolledo
Annabella
A
Codoceo
Juana
J
Inostroza
Jorge
J
Basfi-Fer
Karen
K
Papapietro
Karin
K
Rojas
Jorge
J
Pizarro
Fernando
F
Olivares
Manuel
M
D052242:Adiponectin / Q000097:blood*; D000328:Adult; D001823:Body Composition; D015992:Body Mass Index; D015519:Bone Density; D004032:Diet; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass; D006801:Humans; D008875:Middle Aged; D009767:Obesity, Morbid / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*; D011446:Prospective Studies; D015431:Weight Loss / Q000502:physiology; D055815:Young Adult
D052242:Adiponectin