The Effect of Body Composition on Pulmonary Function

Abstract

BackgroundThe pulmonary function test is the most basic test method to diagnosis lung disease. The purpose of this study was to research the correlation of the body mass index (BMI), the fat percentage of the body mass (fat%), the muscle mass, the fat-free mass (FFM) and the fat-free mass index (FFMI), waist-hip ratio (WHR), on the forced expiratory volume curve.MethodsBetween March and April 2009, a total of 291 subjects were enrolled. There were 152 men and 139 female (mean age, 46.3±9.92 years), and they were measured for the following: forced vital capacity (FVC), forced expiratory volume at 1 second (FEV1), and forced expiratory flow during the middle half of the FVC (FEF25-75) from the forced expiratory volume curve by the spirometry, and the body composition by the bioelectrical impedance method. Correlation and a multiple linear regression, between the body composition and pulmonary function, were used.ResultsBMI and fat% had no correlation with FVC, FEV1 in male, but FFMI showed a positive correlation. In contrast, BMI and fat% had correlation with FVC, FEV1 in female, but FFMI showed no correlation. Both male and female, FVC and FEV1 had a negative correlation with WHR (male, FVC r=-0.327, FEV1 r=-0.36; p<0.05; female, FVC r=-0.175, FEV1 r=-0.213; p<0.05). In a multiple linear regression of considering the body composition of the total group, FVC explained FFM, BMI, and FFMI in order (r2=0.579, 0.657, 0.663). FEV1 was explained only fat% (r2=0.011), and FEF25-75 was explained muscle mass, FFMI, FFM (r2=0.126, 0.138, 0.148).ConclusionThe BMI, fat%, muscle mass, FFM, FFMI, WHR have significant association with pulmonary function but r2 (adjusted coefficient of determination) were not high enough for explaining lung function.

Alterations in lung functions based on BMI and Body fat % among obese Indian population at National Capital Region

“…Restrictive type of lung function abnormalities are frequently observed among obese subjects responsible for alteration in respiratory mechanics [60]. Abdominal and thoracic fat deposition are associated with work of breathing [60,61]. Our results indicate a significant decline in the predicted values of both FEV 1 and PEFR with increasing body fat%.…”

“…Several studies reported no significant differences in FEV 1 , FVC, FEV 1 /FVC ratio and FEF between obese and non-obese subjects [1,57,58]. Obesity is the combination of fatty mass and body masculinity, whereas BMI can interpret only body structure [57,59,60].The effects of body fat% on the pulmonary function values have also been examined in the present study, a topic which hasn't received much attention. Our study showed body fat% to be a better indicator of the lung function alterations as compared to BMI.…”

“…Increase in body fat is associated with decline in FEV 1 and FVC by 10 -15 mL [28,60]. Therefore it can be presumed that adiposity impacts negatively on the lung functions [57,59,60]. Abdominal obesity is related to FEV 1 and FVC, whereas body fat alone does not show any relationship with lung functions [60].…”

“…Studies conducted on the lung function status of patients have indicated upper body obesity has a more severe impact on the lung volumes as compared to obese patients with lower body obesity [57]. Increase in body fat is associated with decline in FEV 1 and FVC by 10 -15 mL [28,60]. Therefore it can be presumed that adiposity impacts negatively on the lung functions [57,59,60].…”

“…Generally FEV 1 and FVC are within the normal range among healthy obese subjects [1,25]. Restrictive type of lung function abnormalities are frequently observed among obese subjects responsible for alteration in respiratory mechanics [60]. Abdominal and thoracic fat deposition are associated with work of breathing [60,61].…”