Comparative epidemiology of selected midline congenital abnormalities.

We present comparative epidemiologic characteristics of five congenital abnormalities that have been suggested to result from midline abnormal developmental disturbances: esophageal atresia with or without tracheoesophageal fistula (EA/TEF), imperforate anus with or without fistula (IA/F), omphalocele (OM), bladder exstrophy (BE), and diaphragmatic hernia (DH). The purpose was to assess the extent of epidemiologic similarities among these five defects. Data were collected as part of a population-based case-control study of infants with these defects born to mothers residing in Maryland, Washington, D.C., or Northern Virginia from 1980 through 1987. The estimated annual birth prevalences (per 10,000 live births) and 95% confidence intervals (CI) of these five defects were 0.40 (0.26-0.61) for BE, 1.34 (1.08-1.67) for OM, 1.59 (1.29-1.95) for DH, 2.11 (1.76-2.53) for EA/TEF, and 2.97 (2.55-3.46) for IA/F. The birth prevalence of IA/F and DH increased between 1980 and 1987. In contrast to the other four defects, DH showed a significant male preponderance (rate ratio 1.57, 95% CI 1.03-2.47), a significant white excess (rate ratio white:other, 1.56, 95% CI 1.00-2.48), and a lower proportion of multiple associated defects (30% vs. 46-61%). We concluded from this study that the descriptive epidemiology of diaphragmatic hernia is different from that of the other four defects. This finding may imply differences in etiologic and pathogenetic mechanisms underlying DH.