Applying principles of physics to the airway to help explain the relationship between asthma and gastroesophageal reflux.

Gastroesophageal reflux (GER) and asthma have been linked, but the true nature of this relationship is incompletely understood. Most of the literature examining this association has implicated GER as the factor contributing to asthma. GER has also been linked to conditions of the upper airway like sinusitis and obstructive sleep apnea (OSA), and once again, usually presumed to be the causative factor. While GER seems to be capable of exacerbating airway disease, mounting evidence suggests that airway obstruction is a risk factor for developing GER. This article examines the principles of physics that predict what should occur given the anatomy of the airway and the esophagus, and provides multiple examples of disease associations that appear to support the hypothesis that airway obstruction is a significant risk factor for development of gastroesophageal reflux.