The aim of this study is to measure important components of weight change in patients who
underwent bariatric surgery on measures of fat mass and its distribution and fat-free mass
(FFM) (bone mineral density, skeletal muscle, and specific organs) at 60 months (T60) and 84
months (T84) post-surgery, and to compare compartment sizes with stable weight controls.
Consenting, eligible patients previously enrolled in the ancillary study, "Longitudinal
Assessment of Bariatric Surgery" (LABS), from Weill Cornell and the University of Pittsburgh
will undergo the following measures: total body water by deuterium dilution (fat and
fat-free mass (FFM)), extracellular water by sodium bromide tracer, body density by the
BodPod, whole-body magnetic resonance imaging (MRI) (adipose tissue and its distribution;
skeletal muscle mass; mass of liver, kidneys, heart, and brain), dual energy-X-ray
absorptiometry (femur bone mineral density (BMD), total body fat, fat-free mass, and bone
mineral content), and resting energy expenditure (REE). MRI will describe body composition
changes at the tissue/organ level and adipose tissue distribution allowing us to address
questions of biological and clinical importance including the body composition changes'
influences on REE. The specific aims are to: 1) measure important components of weight
change in patients who underwent bariatric surgery on measures of fat mass and its
distribution and FFM (including bone mineral density, skeletal muscle, and specific organs)
at T60 and T84 months following surgery, and also to compare compartment sizes with those
seen in stable weight controls; 2) measure the amount of change in REE at T60 and T84
compared to T0, following weight loss induced by bariatric surgery and to determine its
relation to changes in body composition compartments, and its duration over the follow-up
period. Secondary research questions relate to changes in cardiac structure and function,
physical activity associations with skeletal muscle changes, and adipose tissue depot
changes as predictors of cardiometabolic parameters (glucose metabolism and serum lipid
composition). Subjects will be women and men (n=100) equally distributed between the New
York and Pittsburgh sites.
- Had to have been enrolled in the ancillary study prior to having bariatric surgery
- Are able to come to the laboratory for testing.