Analysis of spirometric variables with increasing body mass index in normal and overweight healthy individuals

Background: The relationship between the parameters of body mass index (BMI) and lung function has been established by numerous studies done earlier. Those studies have been done mainly on obese individuals, but only a very few studies have been done in people with normal BMI or overweight group. Our aim is to analyze the various spirometric variables, namely forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), forced expiratory flow (FEF 25%–75%), and peak expiratory flow rate (PEFR), with respect to increase in the BMI in otherwise normal healthy subjects. Methods: The present study design is a randomized experimental parallel-group study. Sixty individuals who were otherwise healthy without any respiratory illness were selected for this study. Their anthropometric measurements were taken. Based on WHO classification, the subjects were grouped as follows: Group I with a BMI of 18.5–24.9 as a normal weight group and Group II with a BMI of 25–29.9 as the overweight group. Using Medispiror, the spirometric variables were determined. Analysis of spirometric variables, namely FEV1, FVC, FEF 25%–75%, and PEFR, were all done using the appropriate statistical method. Results: The results showed that there was a significant decrease in all spirometric variables except PEFR with an increase in BMI. However, the decrease in FVC was relatively more than the decrease in FEV1. Conclusion: This study can be concluded that there is a significant decrease in spirometric variables, namely FEV1, FVC, and FEF 25%–75%, as the BMI increases even in normal individuals who are not obese.