The sudden infant death syndrome (SIDS) is a difficult condition to define because medical scientists do not yet fully understand its nature. In the typical, SIDS case, an apparently healthy infant, who may recently have suffered some minor respiratory ailment, is put to bed in the evening and is found dead in the crib next morning. The baby shows no signs of having been distressed; autopsy reveals no significant findings to explain the cause of death (Bergman et al. 1974; Golding, Limerick, and Macfarlane 1985).
The Second International Conference on Causes of Sudden Death in Infants, held in Seattle in 1969, described SIDS as “the sudden death of any infant or young child which is unexpected by history, and in which a thorough postmortem examination fails to demonstrate an adequate cause for death” (Bergman, Beckwith, and Ray, eds. 1970). That definition still applies. Physicians make the diagnosis of SIDS by excluding other causes of death in infants between one month and one year.
In attempting to understand SIDS, medical professionals have identified epidemiological patterns that characterize its victims, their parents, and the settings in which SIDS death occur. These characteristics will be discussed in subsequent sections.
Distribution and Incidence
The vast majority of reported and published SIDS cases come from countries and continents in the Earth’s temperate zones (e.g., the United States, Canada, Europe, Australia, New Zealand, Japan, Hong Kong, and Israel) (Golding et al. 1985; Culbertson, Krous, and Bendell, eds. 1988; Guntheroth 1989; Irgens, Skjaerven, and Lie 1989; Lee et al. 1989).