We examined the effects of current respiratory illness (RI) on pulmonary function (PF) in 1,103 subjects who underwent spirometry at schools twice within a 4-month period. Before spirometry, subjects were asked if they had a “cold or other chest illness” during the previous month, and if so, whether they had fully recovered. Those who had not recovered were considered to have an RI.
We found that children without RI at their first PF test who reported RI on retest had significantly lower forced expiratory volume in 1 sec (FEV1) (−0.8%), peak expiratory flow rate (PEFR) (−2.2%), forced expiratory flow between 25–75% of vital capacity (FEF25–75) (−3.5%), and forced expiratory flow at 75% of vital capacity (FEF75) (−5.1%) than those without RI on both test and retest. Restriction of subjects to those without a history of doctor-diagnosed asthma did not appreciably change these findings. Children with hay fever had significantly larger RI-associated decreases for FEV1, FEF25–75, and FEF75, but not PEFR, than those without hay fever. Among asthmatic subjects, those with active asthma had larger RI-associated decreases in FEF25–75 and FEF75, but not PEFR, than those without asthma. There was limited evidence that small airway losses were greater in children less than 12.5 years old.
We conclude that RI in children who are well enough to attend school may reduce expiratory flow rates. These effects are greater for children with active asthma or hay fever than in those without, and may be inversely related to age. Pediatr Pulmonol. 2002; 34:112–121. © 2002 Wiley-Liss, Inc.