title: The effect of body composition on pulmonary function.
abstract: BACKGROUND
  The 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.
  
  
  METHODS
  Between 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 (FEV(1)), and forced expiratory flow during the middle half of the FVC (FEF(25-75)) 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.
  
  
  RESULTS
  BMI and fat% had no correlation with FVC, FEV(1) in male, but FFMI showed a positive correlation. In contrast, BMI and fat% had correlation with FVC, FEV(1) in female, but FFMI showed no correlation. Both male and female, FVC and FEV(1) had a negative correlation with WHR (male, FVC r=-0.327, FEV(1) r=-0.36; p<0.05; female, FVC r=-0.175, FEV(1) 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 (r(2)=0.579, 0.657, 0.663). FEV(1) was explained only fat% (r(2)=0.011), and FEF(25-75) was explained muscle mass, FFMI, FFM (r(2)=0.126, 0.138, 0.148).
  
  
  CONCLUSIONS
  The BMI, fat%, muscle mass, FFM, FFMI, WHR have significant association with pulmonary function but r(2) (adjusted coefficient of determination) were not high enough for explaining lung function.
authors.affiliation: Department of Internal Medicine, Regional Center for Respiratory Disease, Yeungnam University Medical Center, Yeungnam University College of Medicine, Daegu, Korea.
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Park
authors.forename: Jin Hong
authors.initials: JH
authors.lastname: Chung
authors.forename: Kwan Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: Kyeong Cheol
authors.initials: KC
authors.lastname: Shin
keywords: Body Compostion; Factor Analysis, Statistical; Pulmonary Function Tests