Mite-impermeable encasings are effective in reducing the number of mite-sensitized children with asthma attending the hospital with asthma exacerbations but not the number requiring oral prednisolone. This simple measure may reduce the health care burden of asthma exacerbations in children. Clinical trial registered with www.isrctn.com (ISRCTN 69543196).

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Rationale: Cough is one of the principal symptoms of chronic obstructive pulmonary disease (COPD) but the potential drivers of cough are likely to be multifactorial and poorly understood. Objectives: To quantify cough frequency in an unselected group of subjects with COPD and investigate the relationships between cough, reported sputum production, smoking, pulmonary function, and cellular airway inflammation. Methods: We studied 68 subjects with COPD (mean age, 65.6 6 6.7 yr; 67.6% male; 23 smokers; 45 ex-smokers) and 24 healthy volunteers (mean age, 57.5 6 8.9 yr; 37.5% male; 12 smokers; 12 nonsmokers). Subjects reported cough severity, cough-specific quality of life, and sputum expectoration and performed spirometry, sputum induction, cough reflex sensitivity to capsaicin, and 24-hour ambulatory cough monitoring. Measurements and Main Results: COPD current smokers had the highest cough rates (median, 9 coughs/h [interquartile range, 4.3-15.6 coughs/h]), almost double that of COPD ex-smokers (4.9 [2. 3-8.7] coughs/h; P ¼ 0.018) and healthy smokers (5.3 [1.2-8.3] coughs/h; P ¼ 0.03), whereas healthy volunteers coughed the least (0.7 [0.2-1.4] coughs/h). Cough frequency was not influenced by age or sex and only weakly correlated with cough reflex sensitivity to capsaicin (log C5 r ¼ 20.36; P ¼ 0.004). Reported sputum production, smoking history, and current cigarette consumption strongly predicted cough frequency, explaining 45.1% variance in a general linear model (P , 0.001). In subjects producing a sputum sample, cough frequency was related to current cigarette consumption and percentage of sputum neutrophils (P ¼ 0.002). Conclusions: Ambulatory objective monitoring provides novel insights into the determinants of cough in COPD, suggesting sputum production, smoking, and airway inflammation may be more important than sensitivity of the cough reflex.Keywords: cough; smoking; sputum; neutrophils; capsaicin Chronic obstructive pulmonary disease (COPD) is a major public health problem, with a lifetime risk in smokers of 35-50% (1). By 2020, it is estimated that more than 200 million people will have COPD, and it will be the third leading cause of death worldwide. Cough (either with or without sputum) is one of the principle symptoms of COPD, along with breathlessness. Epidemiologic studies have found that the reported presence of chronic cough and mucus hypersecretion in established COPD may be linked to accelerated decline in lung function (2), more frequent exacerbations (3), and hospitalizations (4), yet little is known about the mechanisms underlying coughing (5).The potential drivers for cough in patients with COPD are multifactorial. Excessive airway mucus may provide a mechanical stimulus to coughing, especially in the presence of ciliary dysfunction, airflow obstruction, and airway collapse (caused by destruction of the supporting parenchyma), all of which impair clearance. In addition the inflammation, infection, and in some continuing exposure to cigarette smoke provide chemical stimuli capable of provok...