The role of cigarette smoking on persistent airflow obstruction in asthma

In developed countries approximately one-quarter of adults with asthma are active cigarette smokers. These individuals have poorly controlled symptoms, impaired therapeutic responses to corticosteroids, and increased rates of health care utilization compared to nonsmokers with asthma. Persistent airflow obstruction can develop in asthma, particularly in smokers. Accelerated loss of lung function in adulthood as well as genetic, environmental risk factors (other than smoking), and submaximal lung growth in childhood may also contribute to the development of persistent airflow obstruction in smokers with asthma. The best strategy for managing symptoms due to persistent airflow obstruction in smokers with asthma is uncertain and, in particular, which recommendations from international guidelines for asthma or COPD are most appropriate for the management of this patient group.