| Popis: |
Background Overnight allergen exposure from bedding and other sources is thought to be an important driver of atopic asthma. We aimed to test the hypothesis that overnight particulate matter exposure is associated with day-to-day symptoms, lung function and airway inflammation in patients with asthma and house dust mite sensitisation. Methods We undertook a prospective single-centre panel study in 28 adults with asthma and house dust mite sensitisation. Overnight exposure to particulate matter was measured using a commercially available indoor air quality monitor (Cair, NuWave Sensors, Dublin, Republic of Ireland). Symptom scores, peak expiratory flow and exhaled nitric oxide were measured and electronically recorded on a daily basis. In a subset of participants (n=15), reliever inhaler usage was objectively measured using an electronic inhaler casing (Smartinhaler, Adherium, Auckland, New Zealand). Participants were followed up for 12 weeks and attended study visits every 4 weeks, at which they underwent spirometry and completed the Asthma Control Questionnaire and Asthma Quality of Life Questionnaire. Data were analysed using cross-correlation and linear mixed effects models. Results Exposure monitoring using the Cair sensor was reliable, with a 7.1% missing data rate. Particulate matter exposure was highest in the early evening and morning, but was relatively low during the overnight period. No significant associations were observed between overnight particulate matter exposure and daily clinical outcomes (symptom scores, reliever inhaler use, peak expiratory flow and exhaled nitric oxide), or outcomes measured at study visits (Asthma Control Questionnaire, Asthma Quality of Life Questionnaire and spirometry). Conclusions Natural variability in overnight particulate matter exposure does not appear to be a major determinant of day-to-day symptoms, lung function or airway inflammation in patients with asthma and house dust mite sensitisation. Further studies are needed to elucidate the role of the whole exposome in determining daily asthma control. |
