Association between Asthma Severity and Obesity in Two Asthma Clinics in Tehran

The prevalence of both obesity and asthma has increased in recent years. Thus we decided to investigate the relation between obesity and asthma severity. We undertook a cross-sectional study in outpatient asthma clinics of 2 tertiary hospitals in Tehran. Obesity was defined as a body mass index greater than 30. Asthma severity was defined by using the Guide for Asthma Management and Prevention 2004 guidelines, according to patients’ clinical and/or spirometerical parameters. Active cigarette smoking patients and patients with a history of other lung diseases were excluded. A total of 116 individuals, aged 16-83 years with a mean age of 46.57±15.05 years, met the entry criteria. There were 73 females and 43 males. The prevalence of obesity in our study population was 29.3%. The Spearman correlation coefficient between asthma severity and body mass index was r= 0.275 (p= 0.001). Mean body mass index of females and males were 28.95±5.41 and 25.17±4.17, respectively. Mean body mass index of females with asthma was significantly higher than males (p< 0.0001). The odds ratios for obesity were 8.650, 8.746, and 22.491 for mild, moderate and severe persistent asthma, respectively, compared to patients with mild intermittent asthma. With increasing asthma severity, we observed higher occurrence of obesity in adults. The association of asthma severity with obesity suggests that obesity may be a potentially modifiable risk factor for asthma or asthma exacerbation.