Adolescent Asthma and Severe and Moderate Childhood Croup

Although sporadic studies have expressed an association between croup and childhood asthma, the relationship is still ambiguous. So far, no studies have been performed to evaluate the relationship between severe croup and adolescent asthma, especially in Iran. The purpose of this study was to find any relation between moderate and severe croup and future asthma. In 2010-2011, a historical cohort analysis was performed on 164 adolescents who had been admitted to hospitals in Isfahan, Iran due to croup during their childhood (case group). A control group with the same age range and gender was also selected by convenient sampling method from secondary schools in the province. Both groups were called upon to perform spirometry. Spirometric results in the two groups were compared with chi-square test. In this study, 164 adolescents aged 13.7 ± 2.2 years with a history of croup (mean age at diagnosis 2.9 ± 1.3 years) were evaluated as the case group. The same number of adolescents without a history of croup were considered as the control group. Spirometry before and after 15 minutes of exercise revealed 30 cases (18.3%) and 17 controls (10.4) to have asthma (decreased FEV1/FVC or FEF25-75) (P = 0.01). The reductions in FEV1/FVC were more than 15% in 9 patients (5.5%) in the case and 7 (4.2%) in the control groups (P < 0.05). Moreover, FEF25-75 reductions more than 15% were observed in 21 cases (12.8%) and 10 controls (6.1%) (P = 0.001). The prevalence of croup was higher in boys than girls (P = 0.02). It seems that the inflammation caused by moderate and severe childhood croup might result in a series of inflammatory processes in the airways, especially the small airways and the individuals will be prone to asthma and decreased FEV1/FVC and FEF25-75 in adolescence.