[Sudden infant death: epidemiology]

Since 1985, in order to understand variations and factors related to the SIDS compared with the other causes of postneonatal deaths, several epidemiological studies have been carried out in France. The main results obtained so far are presented in this paper. The national rate of SIDS in France is estimated at 1.2 per 1,000 live births. The only specific risk factor for SIDS is age (2-4 months), though birthweight, prematurity and the younger age of the mother increase the probability of dying in the same manner as for accidental causes and all other postneonatal deaths. In addition we found discrepancies in the SIDS rates of babies according to the month of birth. The total probability of dying during the postneonatal period is lower in babies born during spring than in babies born during late summer or autumn. No significant differences were found in the DTP IPV immunization rates between SIDS and other causes of death or between SIDS and living controls.