Background/aims: The reported incidence of biliary atresia varies from 5 to 32/100000 live births. The existence of seasonality and/or clustering is controversial. Based on a large population analysis, we examined the incidence of biliary atresia in France, and the space-time distribution of cases.
Methods: All patients with biliary atresia living in France and born in the years 1986-96 were recorded. Geographic distribution, seasonality, time clustering and space-time clustering were analysed. Statistical analysis used the Chi square test, the Spearman nonparametric correlation test, the Walter and Elwood test for seasonality of events and Knox analysis for time and space-time clustering.
Results: We identified 461 patients: 421 born in metropolitan France (incidence 5.12 [4.63-5.61]/100000 live births), and 40 born in overseas territories. No significant regional variation in incidence was found in metropolitan France, while the incidence was higher in French Polynesia (incidence 29.4 [15.4-43.3]/100000 live births) (p<0.001). Seasonality, time-clustering and time-space clustering could not be demonstrated.
Conclusions: 1) The incidence of BA was 5.7-fold higher in Polynesia than in metropolitan France. 2) Neither seasonal variation in incidence nor clustering was identified.