Association of Body Mass Index with Asthma Severity and Pulmonary Function among Asthmatic Children

Background Asthma is a chronic inflammatory disease in respiratory system and obesity is another inflammatory disease of which incidence rate is increasing. Although, many studies have been conducted on severity of asthma and its relationship with obesity, but different results have been obtained. This study aimed to determine a relationship between BMI with asthma severity and pulmonary function in Kurdistan province, Iran. Materials and Methods: In this cross sectional study 90 asthmatic patients referred to tertiary referral hospital in Kurdistan, North West of Iran, were selected by simple random method. Body mass index (BMI) was calculated by dividing weight by height. Pulmonary Function Test (PFT) and bronchial-stimulation-test were used for confirmation and investigation of asthma severity. Data were analyzed using SPSS-15 and Chi-square and spearman correlation coefficient tests. Results: Relationship between BMI and severity of asthma (mild, medium and severe) was evaluated, there was a weak and positive relationship between them (P<0.05, r=0.23). There was a significant difference between spirometry indices in different levels of BMI variable (P<0.05). There was no significant relation between Forced expiratory volume in 1st second/Forced Vital Capacity (FEV1/FVC) and waist size (P>0.05), but there was a significant and inverse correlation between waist size and other parameters such as (FEV1, FVC and forced expiratory flow [FEF25-75]) (P<0.05). Furthermore, there was a significant and inverse correlation between spirometry indices and Waist-Hip ratio (P<0.05). Conclusion It seems that attention to BMI in people with pulmonary diseases including asthma can help improve clinical and physiological conditions of the person.