Mitchell E A, Williams S M
Department of Paediatrics, University of Auckland, New Zealand.
Acta Paediatr. 2003 Sep;92(9):991-3.
Sudden infant death syndrome (SIDS) is known to occur more frequently at night. In two studies it has now been shown that a prone sleep position is more strongly associated with SIDS occurring during the day, whereas night-time deaths are more strongly associated with maternal smoking and illness.
This variation, although unexplained, does suggest at least two SIDS subtypes: one related to sleep position and possibly a thermal mechanism, and one related to an uncontrolled inflammatory response to infection predominantly occurring at night. In addition, there are probably other mechanisms that do not show a circadian variation.
