Measuring Trends in Infant Mortality Due to Unintentional Suffocation

To the Editor We read with interest the article by Gao et al,¹ who described an increase in unintentional infant suffocation from 1999 to 2015 in the United States, which was “primarily a result of increases in deaths from suffocation and strangulation in bed.”¹ Unfortunately, this study did not fully acknowledge that increased rates in accidental suffocation and strangulation in bed (ASSB) have been partly attributed to diagnostic shifts.² Since about 1999, cause-of-death certifiers (medical examiners and coroners) have been moving away from reporting sudden infant death syndrome (SIDS) as a cause of death to other sudden unexpected infant death (SUID) causes such as ASSB.² In 1990, 84% of SUIDs were certified as SIDS and 2% as ASSB. In 2015, 42% of SUIDs were certified as SIDS and 25% as ASSB.²