Asthma in smokers: challenges and opportunities.

PURPOSE OF REVIEW

Cigarette smoking in asthma is associated with poor symptom control and reduced sensitivity to corticosteroids. We summarize recent evidence supporting the adverse effects of smoking in asthma and consider strategies to manage these patients.

RECENT FINDINGS

Smokers have more severe symptoms and are more likely to be admitted to hospital due to poorly controlled asthma compared with nonsmokers with asthma. Possible causes of reduced sensitivity to inhaled corticosteroids in smokers with asthma are noneosinophilic airway inflammation, impaired glucocorticoid receptor function, and/or reduced histone deacetylase activity. Smoking cessation improves asthma control, but quit rates are low. The optimal drug therapy for smokers with asthma is not established due, in part, to the small number of clinical trials performed in these patients. Preliminary data, however, suggest that leukotriene-receptor antagonists may have a beneficial effect in smokers with mild asthma.

SUMMARY

Cigarette smoking in asthma is a risk factor for poor asthma control and reduced sensitivity to corticosteroids. Every effort should be made to encourage individuals with asthma who smoke to quit. Clinical trials are required to identify therapies that restore corticosteroid sensitivity or directly improve symptom control in individuals with asthma who are unable to stop smoking.