Page 36 - Comprehensive treatment of patients with glucocorticoid-dependent severe asthma

Chapter 2
Environmental pollutants
Smoking of cigarettes and exposure to second hand smoke [39] as well as environmental pollutants, including traffic related pollutants [40-43], nitrogen dioxide [41;44], ozone [44;45] and fine particles [46] are well documented environmental factors that increase asthma severity and promote exacerbations.
Cigarette smoke is probably the strongest known environmental factor influencing asthma severity [47]. Patients with asthma who smoke have more severe symptoms [48], and reduced sensitivity to inhaled corticosteroids [49;50], and are more likely to be admitted to hospital for asthma than non- smokers with asthma [51]. Smoking cessation programs are extremely important for these patients and have been shown to improve lung function and asthma control [52].
Also exposure to environmental tobacco smoke in nonsmoking patients with asthma is associated with worse lung function, higher risk of exacerbations, more health care utilization, and greater bronchial reactivity [47]. Remarkably, the implementation of a smoke free public places law was associated with significant fewer asthma emergency department visits among both adults [53] and children [54].
Short- and long-term exposures to outdoor pollution, in particular traffic exhausts have adverse effects on asthma symptoms [44], lung function [43], and airway inflammation [43;55], whereas reduction of air pollution exposure contributes to improved respiratory health [56-58]. Therefore, reduction of indoor pollution, in particular second hand smoke, and avoidance of outdoor pollution, for example by moving house to less polluted areas, might become part of the integral management of patients with severe asthma.
34