The changing epidemiology of SIDS following the national risk reduction campaigns.

Prone sleeping position is causally associated with SIDS. The change in the proportion of infants sleeping prone has resulted in a dramatic reduction in SIDS and total postneonatal mortality. The effect of prone sleeping position is modified by season, latitude, illness, thermal insulation and sheepskins. This suggests that the mechanism by which prone sleeping position causes SIDS is in some way related to temperature.