Descriptive epidemiology of alimentary tract atresia.

A study has been made on certain epidemiological characteristics of infants with alimentary tract atresia: esophageal atresia, small and large gut atresia, and anal atresia. Data were collected from three malformation registries and represent a material of more than 4.5 million births. A total of 3,550 infants with alimentary atresia were identified corresponding to a total rate of about 8 per 10,000 births. In 167 infants (4.7%) more than one of the major atresia types were present simultaneously. Racial differences were found (based on data from California) for esophageal atresia where whites had a higher rate than other races. For gastrointestinal atresia, a high rate in blacks was found, while no differences between races were seen for anal atresia. Also, differences in registered rates between the three programs were found, at least partly explainable by different ascertainment. The different forms of atresia were compared from the point of view of sex ratio, twinning rate, maternal age and parity distribution, presence of chromosome anomalies, and types of associated malformations. The pathogenesis and etiology of the various types of atresia are discussed based on these observations. The conclusion is that although undoubtedly other pathogenetic mechanisms may exist for gastrointestinal atresia, a substantial proportion of all infants with alimentary atresia had their malformations as a result of early disturbances of intestinal morphogenesis. Within each subgroup, apparently different etiologies may exist, resulting in differences in epidemiological characteristics.