Correlation of Body Composition with Pulmonary Function in Adults

Context: General population has a wide variation in physical activities ranging from the people with sedentary lifestyle to people involved in regular physical activity; there is also variation amongst different age group. All these factors may produce wide variation in body composition and this in turn affects pulmonary function.
Aims: To see the correlation between various PFT parameters and various body composition parameters like body mass index (BMI), the fat percentage of the body mass (fat%), the fat-free mass (FFM), and the fat-free mass index (FFMI).
Settings and Design: Cross sectional study which was done on attendants of the patients visiting AIIMS Bhopal OPD
Methods and Materials: Two hundred and twenty three subjects (152 male and 71 female) in the age group of 18 to 48 years underwent the pulmonary function test and body composition assessment. Body composition was assessed using sex matched prediction equation based on skin fold thickness.
Statistical Analysis Used: Univariate correlation coefficient (Pearson) was used to check the relationship between various PFT parameters and body composition.
Results: In males, Fat percentage showed significant negative correlation with FEV1 (r=-0.198, p=0.014) and FEF 25-75%, p=0.0005). Fat free mas showed non-significant positive correlation with the most of the PFT parameters and fat free mass index showed significant negative correlation with the FEV1(r=-0.164, p=0.04) and PIFR.(r=-0.174, p<0.0001). In females significant positive correlation was seen only between fat free mass and FVC. (r=0.32, p=0.005).
Conclusion: Body composition has a predominant effect on pulmonary function test in males. In females, some effect is also seen. So we recommend body composition assessment for PFT interpretation.