The effect of positions on spirometric values in obese asthmatic patients.

Obesity as a common health risk is increasing all over the world. The aim of this study was evaluation of standing and sitting positions on spirometric values in obese asthmatic patients, in comparison with normal obese subjects. The study included 49 obese asthmatic patients with mean age of 42.63 years and body mass index of 36.06 kg/m2, and 51 control obese normal subjects with mean age of 39.86 years and body mass index of 36.69 kg/m2. Subjects with body mass index of (BMI) > or =30 kg/m2 were enrolled in the study. Spirometric values were measured according to American Thoracic Society (ATS) recommendation. In both groups forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were measured in sitting and standing positions, and the results were compared. The mean+/-SD of FVC in sitting and standing positions in obese asthmatic patients were: 3.04+/-0.93 lit and 3.03+/-0.96 lit, p=0.37; and in control group: 3.68+/-1.12 lit and 3.72+/- 1.11 lit, p=0.39, respectively. The mean+/-SD of FEV1 in the sitting position and standing positions in obese asthmatic patients were: 2.38+/- 0.75 lit and 2.40+/- 0.81 lit, p=0.20; and in control subjects: 3.17+/- 0.92 lit and 3.21+/- 0.93 lit, p=0.07. This study showed that spirometric values in obese asthmatic patients with BMI> or =30 are not affected by the standing and sitting positions.