RT Journal Article
SR Electronic
T1 Cough frequency in children with mild asthma correlates with sputum neutrophil count
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP 747
OP 750
DO 10.1136/thx.2005.050815
VO 61
IS 9
A1 A M Li
A1 T W T Tsang
A1 D F Y Chan
A1 H S Lam
A1 H K So
A1 R Y T Sung
A1 T F Fok
YR 2006
UL http://thorax.bmj.com/content/61/9/747.abstract
AB Background: A study was undertaken to measure cough frequency in children with stable asthma using a validated monitoring device, and to assess the correlation between cough frequency and the degree and type of airway inflammation. Methods: Thirty six children of median age 11.5 years (interquartile range (IQR) 9–14) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring for 24 hours. Coughing episodes were counted both as individual spikes and as clusters. Results: All children had mild intermittent asthma and their median forced expiratory volume in 1 second and eNO were 83.3% (IQR 81.1–97.6) and 56.1 ppb (IQR 37.4–105), respectively. The median number of cough episodes per day was 25.5 (IQR 16–42.8). Sputum induction was successful in 69% of the subjects and cough frequency was found to have a significant positive correlation with sputum neutrophil count (r = 0.833, p = 0.0001). Conclusions: Children with stable mild asthma have increased cough frequency that might be driven by a neutrophilic inflammatory pathway.