Introduction: Asthma is associated with airflow limitation and increased decline in lung function. The underlying mechanism for this was probably that persisting inflammation leads to remodelling of the airways.
Objectives: To review the importance of different factors which are related to airflow limitation and lung function decline in asthma.
Methods: Case report and literature review.
Results: Asthma severity, smoking, bronchial hyperresponsiveness and eosinophil inflammation were the variables that were most convincingly related to decline in forced expiratory volume in 1 s (FEV(1)) in asthma. Treatment with inhaled corticosteroids probably decreased the rate of FEV(1) decline, although this was more uncertain because of the lack of randomised double blind studies that show such an effect. Progress in the field of the genetics of asthma may, in the near future, elucidate the role of gene-environment interaction in lung function decline in asthma.
Conclusion: Regular treatment with inhaled corticosteroids may partly have a beneficial effect on airway remodelling in asthma. Improved understanding of the processes leading to airway remodelling is, however, important in order to prevent a large number of asthmatics from developing irreversible airflow obstruction.