The majority of additional explanations suggest that reflux causes respiratory symptoms rather than vice versa. Heightened bronchial reactivity, microaspiration, and a vagally mediated reflex mechanism are possible pathways. Exposure to small amounts of acid has recently been proposed to result in impaired laryngopharyngeal sensitivity and thereby potentially increasing the risk of aspiration. It has also been suggested, however, that asthma causes or aggravates reflux. Airflow obstruction due to asthma might increase the negative pleural pressure and thereby increase the pressure gradient over the diaphragm. Furthermore, it has been suggested that bronchodi-lator medication might predispose to gastroesophageal reflux. Theophylline has been shown to stimulate gastric acid secretion and lower the pressure of the lower esophageal sphincter, effects that could cause or intensify reflux symptoms. Similarly, (3-ad-renergic agonists might relax the lower esophageal sphincter, especially when systemically administered. more
Hence, the literature on the mechanism underlying the association between reflux and respiratory symptoms is not conclusive. Avidan et al investigated the temporal association between coughing or wheezing and reflux episodes in asthmatics and concluded that even though occasional coughing can lead to reflux, the opposite is far more common. They found that almost half of all coughs and wheezes were associated with reflux. This finding implies that the respiratory symptoms might be alleviated by antireflux treatment. Indeed, several studies have focused on this issue; in the majority of them, improvements in asthma symptoms but not in objective measures of pulmonary function were noted after antireflux therapy, both medical and surgical. However, in a recent study, treatment with esomeprazole twice daily did improve morning peak expiratory flows in adult asthmatics.
Our results might have clinical relevance. The associations reported point to the need to consider reflux symptoms as a cause or contributory factor of respiratory disorders, particularly those respiratory problems that do not respond well to conventional treatment. Antireflux therapy might be an alternative treatment that could better help some of these patients. It is important that primary health-care physicians be aware of the association between respiratory disorders and reflux symptoms, since they are the ones who will treat the majority of these patients.
In conclusion, our large population-based study has revealed a strong link between gastroesophageal reflux symptoms and various respiratory disorders. This finding is of clinical relevance, and antireflux therapy might be a valuable therapeutic tool in some patients with respiratory disorders.