Background
Among respiratory diseases, asthma is one of the most burdensome disorder worldwide. Growing evidence disclose gut dysbiosis may contribute to asthma via the gut-lung axis. Constipation can lead to alteration of the gut microflora. The clinical impact of constipation on asthma has not been researched. Therefore, we aim to assess the risk of asthma in constipated patients by a nationwide population-based cohort study.