Effects of pollution on swallowing: how little we know.

Swallowing is an essential function of the upper alimentary tract. It is highly complex, requiring precise coordination of numerous nerves and muscles of the oral cavity, pharynx, larynx, and esophagus. Swallowing is integrated with other physiologic functions, including mastication and respiration. Impairments of swallowing may result from many different structural or physiologic disorders. Little is currently known about the direct effects of pollution on swallowing. Structures critical to swallowing, however, are vulnerable to damage by environmental hazards such as exposure to ionizing radiation or intake of toxins by ingestion or inhalation. The relationship of swallowing to environmental lung disease is an area of particular interest because impaired swallowing may result in aspiration of food particles into the lung, and because pollutants may hamper airway defense mechanisms. In this article, we discuss the possible impact of selected environmental agents on swallowing and suggest future directions for research.