Association of childhood croup and increased incidence of airway hyperreactivity in adulthood

Some evidence suggests that childhood croup could be associated with increased incidence of adulthood bronchial reactivity, but its significance is uncertain. The aim of the present study was to evaluate the long‑term outcome of early life croup.

This case–control study was conducted in 2010–2012 in Isfahan, Iran. The case group consisted of 164 adolescents with a history of severe croup in early life and an equal number of healthy controls without any history of croup or other chronic or recurrent respiratory diseases. The two groups were compared according to pulmonary function tests and bronchial reactivity (exercise challenge test). Statistical analyses were performed using the SPSS software package, version 20 (SPSS Inc., Chicago, IL, USA). P < 0.05 was considered significant.

Baseline spirometric values (forced expiratory volume in 1st s (FEV1), forced volume capacity (FVC), FEV1/FVC, and forced expiratory flow at 25%–75% (FEF25–75) were similar in case and control groups. A reduction in FEV1 and FEF25–75 after exercise challenge test was seen in 9% and 12.8% of patients, respectively, whereas this was reduced in only 4.2% and 6.1% of the controls (P = 0.034 and P = 0.021, respectively).

Our findings suggest that childhood croup might be a predisposing factor for bronchial hyperreactivity in adulthood. Longitudinal studies are necessary to confirm the clinical significance of these findings.