title: Dynamics of change in total and regional body composition after gastric bypass in obese patients.
abstract: Little is known on patterns of change over time in body composition, especially lean body mass (LBM), during massive weight loss after Roux-en-Y gastric bypass (RYGB) in obese patients. We performed sequential measurements of total and regional body composition in patients after RYGB, and we compared a subsample of patients after surgery to a nonsurgical control group of similar age and body fatness. We used dual-energy X-ray absorptiometry (DXA) before and at 3, 6, and 12 months after RYGB in 42 obese women (before surgery: age 39.5 +/- 11.6 years; BMI 44.6 +/- 6.1 kg/m(2); mean +/- s.d.) and in 48 control obese women referred for nonsurgical weight management, before weight loss. During 1-year follow-up after RYGB, there was a continuous decrease in body weight (-36.0 +/- 12.5 kg at 1 year), total fat mass (FM) (-26.0 +/- 9.1 kg), as well as in trunk and appendicular FM. In contrast, the decrease in total LBM (-9.8 +/- 4.8 kg at 1 year), as well as in trunk and appendicular LBM, plateaued after 3-6 months. Rates of loss in weight, FM, and LBM were highest during the first 3-month period after RYGB (6.4 +/- 1.8, 4.1 +/- 1.7, and 2.3 +/- 1.2 kg/month, respectively), then decreased continuously for FM but plateaued for LBM. There was no evidence of a decrease in total, trunk, or appendicular LBM in weight-reduced subjects compared to the control group. In conclusion, follow-up of these obese women revealed a differential pattern of change in FM and LBM after RYGB. Despite an important loss in LBM, especially during the 3-6 months of initial period, LBM appears to be spared thereafter.
authors.affiliation: Department of Nutrition, Pitié-Salpêtrière Hospital (AP-HP), University Pierre et Marie Curie-Paris6, Human Nutrition Research Center (CRNH-Ile de France), Paris, France.
authors.forename: Cecile
authors.initials: C
authors.lastname: Ciangura
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Bouillot
authors.forename: Celia
authors.initials: C
authors.lastname: Lloret-Linares
authors.forename: Christine
authors.initials: C
authors.lastname: Poitou
authors.forename: Nicolas
authors.initials: N
authors.lastname: Veyrie
authors.forename: Arnaud
authors.initials: A
authors.lastname: Basdevant
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Oppert
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D050154:Adiposity; D000328:Adult; D000704:Analysis of Variance; D001823:Body Composition; D001835:Body Weight; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome; D015431:Weight Loss