Study objectives: To determine the relationship between
weight-loss and pulmonary function indexes, focusing on forced
expiratory flows (ie, FEV1, forced
expiratory flow at 50% of vital capacity [FEF50], forced
expiratory 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/m2), without
significant obstructive airway disease, were selected from among
participants in a weight-loss program.
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
(ie, body weight [BW], BMI, the sum skinfold
thicknesses, thoracic inhalation circumference, thoracic expiration
circumference, total FM, and trunk FM [FMtrunk]) were significantly
decreased (p ≤ 0.0001) after a hypocaloric diet. The mean vital
capacity, FEV1, FEF50, FEF25–75,
expiratory reserve volume, and MVV significantly increased
(p ≤ 0.05) with weight loss. The correlation coefficient forΔ
FEF25–75 (r = 0.20) was numerically
higher than ΔFEF50 and ΔFEV1
(r = 0.14 and r = 0.08, respectively)
for the BW loss. Moreover, the correlation coefficient forΔ
FEF25–75 (r = 0.45) was significantly
higher (p ≤ 0.02) than those for ΔFEF50 andΔ
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