Determining the Relationship between Body Composition and Lung Functions among Middle Aged Obese Subjects

Background: Obesity is a major health hazard in developed and developing countries. It is proved to be a co-morbid condition in various metabolic, cardiovascular and pulmonary disorders. Only few studies have carefully examined the relationship of lung functions with body composition among middle aged obese. Objectives: To explore the relationship between body composition and their influence on pulmonary functions among obese middle aged subjects. Methods: 100 obese healthy subjects of age 35-55 years were included in the study. BMI, Body fat percentage (BF %), Fat Mass (FM) were estimated and Fat Free Mass (FFM) was calculated using predicted equations. All the recordings were done at same time of the day, 10am to 12noon. at ambient temperature and environment and respiratory parameters such as Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), FEV1/FVC, Peak Expiratory Flow Rate (PEFR), Mean forced expiratory flow during the middle of FVC (FEF25-75%), Maximum Voluntary Ventilation (MVV) were assessed. Unpaired t-test Pearson’s correlation coefficient were used to analyze the variables. Results: Mean BMI of study subjects was 31.9±1.78 kg/m2. A non-significant inverse correlation of FM with FVC and FEV1 was observed. The Correlation coefficient of FM and FEV1 / FVC ratio showed a negative non-significant relation. There was no relation between FM and FEF25-75%. A significant positive correlation was observed between FM and PEFR among obese subjects. The correlation of FFM with FEF25-75% and MVV was significantly positive (r = +0.65 and r = +0.94 respectively). P values 0.05 were considered statistically significant. Conclusions: Pulmonary functions are more closely associated with fat distribution than with the extent of obesity. It is important to take into account the body composition instead of BMI alone while determining early changes in lung functions among middle aged obese.