Between November 2006 and February 2009, participants (n=64) enrolled in the Longitudinal Assessment of Bariatric Surgery-2 (LABS-2) at Weill Cornell Medical College and University of Pittsburgh Medical Center sites were enrolled in this ancillary study [12 (link)–14 (link)]. Due to recruiting delays, 41 additional participants were enrolled through December 2009 for a total of 105 participants, 53 from Weill Cornell and 52 from Pittsburgh.
Only Weill Cornell subjects were included in this analysis because BIA and reference measurements were not collected concomitantly in Pittsburgh. Three participants did not undergo bariatric surgery and were excluded, leaving an analysis sample of 50. All studies were approved by the Institutional Review Board of St. Luke’s-Roosevelt Hospital, and written informed consent was obtained.
Baseline measures were obtained on average 1.3 week before surgery (T0; range 0–11 week) and postoperative measures were approximately 12 months later (T12; range 10.6–17.7 months) at St. Luke’s-Roosevelt Hospital. A self-report medication log was obtained and checked against pill bottles and medical records when available. Exclusion criteria included pregnancy, abnormal thyroid or cortisol levels, and self-report of medications known to influence body composition (e.g., diuretics and corticosteroids). After chart abstraction, four subjects were identified to be on hydrochlorothiazide, a diuretic, and at baseline.
Weight (Weight Tronix, New York, NY; and Scale-Tronix, Wheaton, IL), height (Holtain; Crosswell, Wales-New York), BIA (Model TBF-310, Tanita Inc., Arlington Heights, IL), and body density (Bod Pod; (Cosmed, Chicago, IL; software version 2.3) [15 (link), 16 (link)] measurements were obtained [17 (link)]. TBW was measured using a D2O (~1 g/kg) oral dose administered after a venous blood sample was taken from an antecubital vein. After 3 h, a second blood sample was obtained (seeonline supplementary materials for details). A 3C model was used to estimate fat mass [18 (link)]: fat (kg)=2.122×(BW/d) −0.779×TBW −1.356×BW, where BW is the body weight in kilograms, d is the body density derived from BodPod, and TBW is the total body water in kilograms.
Only Weill Cornell subjects were included in this analysis because BIA and reference measurements were not collected concomitantly in Pittsburgh. Three participants did not undergo bariatric surgery and were excluded, leaving an analysis sample of 50. All studies were approved by the Institutional Review Board of St. Luke’s-Roosevelt Hospital, and written informed consent was obtained.
Baseline measures were obtained on average 1.3 week before surgery (T0; range 0–11 week) and postoperative measures were approximately 12 months later (T12; range 10.6–17.7 months) at St. Luke’s-Roosevelt Hospital. A self-report medication log was obtained and checked against pill bottles and medical records when available. Exclusion criteria included pregnancy, abnormal thyroid or cortisol levels, and self-report of medications known to influence body composition (e.g., diuretics and corticosteroids). After chart abstraction, four subjects were identified to be on hydrochlorothiazide, a diuretic, and at baseline.
Weight (Weight Tronix, New York, NY; and Scale-Tronix, Wheaton, IL), height (Holtain; Crosswell, Wales-New York), BIA (Model TBF-310, Tanita Inc., Arlington Heights, IL), and body density (Bod Pod; (Cosmed, Chicago, IL; software version 2.3) [15 (link), 16 (link)] measurements were obtained [17 (link)]. TBW was measured using a D2O (~1 g/kg) oral dose administered after a venous blood sample was taken from an antecubital vein. After 3 h, a second blood sample was obtained (see