Body composition analysis and changes in airways function in obese adults after hypocaloric diet

Study objectives: To determine the relationship between weight-loss and pulmonary function indexes, focusing on forced expiratory flows tie, FEV,, forced expiratory flow at 50% of vital capacity [FEF50], forced expiratoly flow at 75% of vital capacity, and forced expiratory flow at 25 to 75% of vital capacity [FEF25-75]). Specifically, to determine the effect of losses in total and segmental fat mass (FM) and of modifications in lean body mass, after restricted hypocaloric diet, on pulmonary function among obese adults. Design: Cross-sectional, observational. Settings: Human Physiology Division, Faculty of Medicine and Surgery, Tor Vergata University, Rome, Italy. Patients: Thirty obese adults (mean [+/- SD] baseline body mass index [BMI], 32.25 +/- 3.99 kg/m(2)), without significant obstructive airway disease, were selected from among participants in a weight-loss program. Measurements and results: Anthropometric, body composition (BC), and respiratory parameters of all participants were measured before and after weight loss. Total and segmental lean body and FM were obtained by dual-energy x-ray absorptiometry. Dynamic spirometric tests and maximum voluntary ventilation (MVV) were performed. The BC parameters tie, body weight [BW], BMI, the sum skinfold thicknesses, thoracic inhalation circumference, thoracic expiration circumference, total FM, and trunk FM [FMtrunk]) were significantly decreased (p less than or equal to 0.0001) after a hypocaloric diet. The mean vital capacity, FEV1, FEF50, FEF25-75, expiratory reserve volume, and MVV significantly increased (p less than or equal to 0.05) with weight loss. The correlation coefficient for Delta FEF25-75 (r = 0.20) was numerically higher than Delta FEF50 and Delta FEV1 (r = 0.14 and r = 0.08, respectively) for the BW loss. Moreover, the correlation coefficient for Delta FEF25-75 (r = 0.45) was significantly higher (p less than or equal to 0.02) than those for Delta FEF50 and Delta FEV1 (r = 0.38 and r = 0.15, respectively) for FMtrunk loss. Conclusions: This study shows that a decrease in total and upper body fat obtained by restricted diet was not accompanied by a decrease in ventilatory muscle mass. FMtrunk loss was found to have improved airflow limitation, which can be correlated to peripheral airways function.