Obesity and asthma: association or epiphenomenon?

Objective: To relate obesity and asthma by comparing gender, age, initial classification of asthma, clinical control, basal forced expiratory volume in one second (FEV1) and forced expiratory flow between 25 and 75% (FEF25-75%) with rates of body mass index (BMI) in asthmatic adolescents.

Methods: Cross-sectional study involving 120 asthmatics patients (1.9 male: 1 female) with a mean age of 14.1 years (9 to 20.1 years of age), classified according to asthma severity and control, and evaluated by spirometry using their basal FEV1 and FEF25-75%. The data were described by frequency, mean and standard deviation or median and range and analyzed by ANOVA, unpaired t test, Fischer's exact test, Kruskal-Wallis and Pearson's correlation, considering significant p<0.05.

Results: There was no difference between gender in relation to the initial classification and the level of asthma control; 91.7% (100 cases) received initial classification as persistent and 106 cases (88.3%) were partially or totally controlled. There was no statistical difference between controlled patients and the others in relation to BMI. No significant correlations were found between zBMI and FEV1 and between zBMI and FEF25-75%, analyzing all patients and only patients with overweight or obese.

Conclusions: In this study, no significant correlation was found between overweight/obesity and asthma using clinical, anthropometric and spirometric parameters.