Determinants of Overweight and Obesity in Lung Transplant Recipients

Background: Obesity-related diseases have been shown to affect post-lung transplantation survival. An estimated 30% of lung transplant recipients develop overweight. Objective: The aim of this study was to examine the possible determinants of large increases in weight after lung transplantation. The contribution of physical activity, food intake, and resting energy expenditure was examined in lung transplant recipients. Methods: In this cross-sectional study 21 overweight lung transplant recipients (11 men, mean age 57 ± 7 years; BMI 30 ± 3) and 21 normal-weight lung transplant recipients (11 men, mean age 56 ± 5 years; BMI 22 ± 3) were matched for disease, gender, age, prescribed medication, and time since lung transplantation. Physical activity was measured by a pedometer and a questionnaire; resting energy expenditure was measured by the ventilated-hood technique, and daily food intake by a dietician. Additionally, fat-free mass, lower-body strength, and fatigue were measured. Results: The overweight lung transplant recipients had a significantly lower number of steps per day (4,686 ± 3,266 vs. 7,524 ± 3,448 steps/day, p = 0.01) and a lower fat-free mass (64 ± 9 vs. 75 ± 6%, p < 0.05) compared to normal-weight recipients. Obese subjects had a lower percentage of predicted resting energy expenditure level compared to normal-weight recipients (90 ± 14 vs. 100 ± 14% predicted, p = 0.04). Conclusion: Our data suggest that overweight in lung transplant recipients is associated with a lower fat-free mass and lower levels of physical activity and resting energy expenditure compared to normal-weight recipients.