This article includes multiple AASPP members as authors. It was published online in Forensic Science, Medicine, and Pathology in January of 2015:
Sudden infant death syndrome (SIDS) was originally defined in 1969, focusing attention on sudden death in infants without an identified cause. These infants had a similar age at death and a strong association with sleep in common. Naming the sudden death SIDS instead of calling it ‘‘cause unknown’’ facilitated an enhanced focus on parental support and on research. Later studies identified prone sleep as a significant risk factor for SIDS-classified deaths. The definition of SIDS was expanded in 1991, with an emphasis on scene investigation. Although further modifications have been recommended, no consensus has been achieved. Indeed, a review of recent publications reported that the 1969 definition continues to be used 7% of the time, the 1991 definition 35% of the time, other modifications 26% of the time and in 20% no definition was mentioned. Initially there were no candidate etiologies to explain these deaths. In the intervening years, however, much has been learned about environmental, biological, and genetic risk factors for deaths classified as SIDS. Once prone sleep was identified as a significant risk factor, most developed countries implemented back-to-sleep campaigns. SIDS-classified death rates started to decline after 1990, as did non-SIDS-classified postneonatal mortality rates, and continued to decline until 2001. Much of this decline was initially attributed to an overall decrease in SIDS-classified deaths. Since 2001, however, SIDS-classified death rates have not continued to decrease whereas there has been a diagnostic shift to other assigned causes of sudden unexpected infant death or to unknown cause. Illustrating the impact of how these deaths are classified, SIDS-classified deaths declined by 20% from 2005 to 2011, whereas for the same period the rate of accidental infant deaths increased by 5% and rates for undetermined/unclassified deaths also increased.