Epidemiological comparisons of sudden infant death syndrome with infant apnoea.

A unique opportunity to study proven infant apnoea (PIA) and Sudden Infant Death Syndrome (SIDS) occurrences epidemiologically in 12 Counties in north-western Washington State during the same time period during which 180,017 live births were recorded revealed markedly dissimilar distribution patterns. The overall incidence of SIDS exceeded that of PIA by a factor of 3. Five PIA babies subsequently succumbed to SIDS. Statistical analysis reveals that these five events cannot be explained as random coincidences; they represent 3% of 163 PIA cases but only 1% of 503 SIDS occurrences. Infant apnoea is an infrequent precursor of SIDS. These results do not support the view that SIDS and infant apnoea are related conditions caused by a common underlying disorder. Aetiological models other than infant apnoea must be devised if the momentum of SIDS research is to be sustained.