Relation of peak expiratory flow rate to body mass index in young adults

Background: Peak expiratory flow rate (PEFR) is a measure of airflow in bronchial tree and it provides idea of bronchial tone. It is affected by age, sex, height, body weight, and other physical activity. There is evidence that obesity has a link to bronchial hyperresponsiveness. Thus, we proposed this study to find out the relation between PEFR and body mass index (BMI). Materials and Methods: In this study, 56 male and 49 female young subjects (total = 105) were recruited. As sex is a definite factor for variation in PEFR, subjects were classified into normal (BMI = 18–24.99 kg/m2), over weight (BMI = 25–29.99 kg/m2), and obese (BMI = 30–34.99 kg/m2) separately for both male and female. After written consent, PEFR of each subject was recorded between 7 and 8 am. Then, data analysis was done by one-way ANOVA, Pearson correlation, and regression analysis. Results: In male subjects, the mean difference of PEFR of normal, over weight, and obese subjects were 498 L/min, 488 L/min, and 391 L/min, respectively, which is statistically significant (P = 0.000). In female subjects, the mean difference of PEFR of normal, over weight, and obese subjects were 377 L/min, 348 L/min, and 325 L/min, respectively, which is statistically significant (P = 0.002). Pearson correlation showed negative correlation between BMI and PEFR both in male (r = −0.512) and in female (r = −0.539). Conclusion: This study concluded that PEFR declines with increase in BMI, and there is negative correlation between BMI and PEFR.