title: Effects of vertical-banded gastroplasty on bone and mineral metabolism in obese patients.
abstract: The surgical treatment of obesity can have adverse effects on bone, but there are few published data on the effects of vertical-banded gastroplasty. Serial measurements of bone mineral density at the lumbar spine and three upper femoral sites, using dual-energy X-ray absorptiometry, and also of biochemical indices of bone and mineral metabolism at intervals up to 2 years after operation were performed in 18 patients with morbid obesity who had vertical-banded gastroplasty. Bone mineral density measurements were also made in age- and sex-matched non-obese controls. Bone density before operation was significantly greater in the obese than in the controls (P < 0.02 at all sites). The obese patients lost weight rapidly after vertical-banded gastroplasty (mean weight loss 29 kg at 1 year, P < 0.001). This was accompanied by a measurable loss of bone density from the trochanter and Ward's triangle sites in the upper femur (P < 0.05), but not from the lumbar spine. Bone density values remained stable over 14 months in the controls. Hydroxyproline excretion increased significantly (P < 0.005), indicating an increase in bone resorption. Alkaline phosphatase levels decreased significantly (P < 0.001), but this probably represents the reversal of hepatic steatosis. There was no evidence of hyperparathyroidism or vitamin D deficiency. In conclusion, vertical-banded gastroplasty causes modest bone density loss from femoral sites, but not the lumbar spine. The difficulties of assessing bone density changes in the obese are discussed.
authors.affiliation: Department of Medicine, University of Auckland School of Medicine, New Zealand.
authors.forename: T
authors.initials: T
authors.lastname: Cundy
authors.forename: M C
authors.initials: MC
authors.lastname: Evans
authors.forename: R G
authors.initials: RG
authors.lastname: Kay
authors.forename: M
authors.initials: M
authors.lastname: Dowman
authors.forename: D
authors.initials: D
authors.lastname: Wattie
authors.forename: I R
authors.initials: IR
authors.lastname: Reid
mesh_terms: D000328:Adult; D015519:Bone Density; D002118:Calcium / Q000378:metabolism; D004798:Enzymes / Q000378:metabolism; D005260:Female; D015391:Gastroplasty; D006801:Humans; D008297:Male; D008875:Middle Aged; D008903:Minerals / Q000378:metabolism*; D009767:Obesity, Morbid / Q000378:metabolism* / Q000601:surgery; D010281:Parathyroid Hormone / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D011182:Postoperative Care; D011446:Prospective Studies; D013739:Testosterone / Q000378:metabolism; D014807:Vitamin D / Q000378:metabolism
chemical_list: D004798:Enzymes; D008903:Minerals; D010281:Parathyroid Hormone; D010710:Phosphates; D014807:Vitamin D; D013739:Testosterone; D002118:Calcium