Background Gastroesophageal acidity (GE pH) could be related to lung function and airway response to exercise in children with lower airways disease.
Aims To compare GE pH with lung function before and after exercise in asthmatic and non-asthmatic outpatients with recurrent respiratory symptoms.
Methods 16 asthmatic and 15 non-asthmatic patients (aged 4. 5–15.7 yr; M/F 23/8) did lung function before and after 24-h GE pH monitoring (GE pH24). Subjects also undergone exercise-testing (treadmill) 1 hour before GE catheter removal. GE pH was also analysed for 6-minute intervals each (before, during and after exercise).
Results GE pH 24 levels did not correlate with exercise outcomes, nor yielded statistical differences between patient groups. Instead, GE pH24 correlated positively with baseline FEV1 % in asthmatic subjects (r=0.66, p=0.006) whereas correlated negatively in non-asthmatic subjects (r= –0.61, p=0.016).Median (interquartile range, IQR) values of GE pH fall during exercise in asthmatic but not in non-asthmatic children (–4.64, IQR:10.2 vs 0.00, IQR:5.64, p=0.033). Conversely, GE pH values increased 1 hour after exercise only in asthmatic children (5.80, IQR:7.73 vs 0.00, IQR:9.82, p=0.012).
Conclusion Our data suggest a characteristic relationship between GE pH, lung function and airway response to exercise in asthmatic children; whether GE pH is cause or consequence of these bronchial changes remains to be established.