Epidemiology of biliary atresia in France: a national study 1986-96

Background/Aims: The reported incidence of biliary atresia varies from 5 to 32/100 000 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]/100 000 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]/100 000 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

Adrenergic reactions during N3 sleep arousals in sleepwalking and sleep terrors: The chicken or the egg?

To understand the mechanisms of N3 sleep interruptions in patients with sleep- walking episodes and/or sleep terrors (SW/ST), we evaluated whether autonomic reactions preceded or accompanied behavioural arousals from NREM sleep stage N3. In 20 adult patients with SW/ST and 20 matched controls without parasom- nia, heart rate and pulse wave amplitude were measured beat-to-beat during the 10 beats preceding and during the 15 beats succeeding a motor arousal from N3 sleep. Respiratory rate and amplitude were measured during the same 25 successive beats. In patients with SW/ST, the N3 arousals were associated with a 33% increase in heart rate, a 57% decrease in pulse wave amplitude (indicating a major vasoconstriction), a 24% increase in respiratory rate and a doubling of respiratory amplitude. Notably, tachycardia and vasoconstriction started 4 s before motor arousals. A similar pro- file (tachycardia and vasoconstriction gradually increasing from the 4 s preceding arousal and post-arousal increase of respiratory amplitude, but no polypnea) was also observed, with a lower amplitude, during the less frequent 38 quiet N3 arousals in control subjects. Parasomniac arousals were associated with greater tachycardia, va- soconstriction and polypnea than quiet arousals, with the same pre-arousal gradual increases in heart rate and vasoconstriction. Autonomic arousal occurs 4 s before motor arousal from N3 sleep in patients with SW/ST (with a higher adrenergic reac- tion than in controls), suggesting that an alarming event during sleep (possibly a wor- rying sleep mentation or a local subcortical arousal) causes the motor arousal