Achalasia: a critical review of epidemiological studies.

Achalasia is one of the earliest recognized gastroenterological conditions. However, several centuries after it was first described, it remains also among the least understood. One of the main reasons for this is the relative rarity of the disease, which has resulted in limited opportunities to conduct investigative research. Few epidemiological studies have been conducted to date, and their data suggest a worldwide incidence estimated at between 0.03-1.1/10(5)/yr. This review of the literature on the epidemiology of achalasia lends support to the idea that pooling of resources and collaboration at an international level is required, if any significant progress in the cause, treatment, and prevention of the disease is to be made.