According to a study published in the Paediatrics, researchers have confirmed unexplained death risk factors and estimated suffocation risk factors to determine the causes of infant death. Nonapproved sleep surface use is tied with a 4-fold higher risk of suffocation and is not associated with unexplained death. The use of soft bedding is strongly associated with suffocation than unexplained death.
Nearly 3400 US families in 2019 experienced infant death related to accidental suffocation, strangulation, and sudden infant death syndrome (SIDS). Many causes were unknown.
There need to be more studies to examine risk factors for sudden infant deaths unexpectedly since 2000. There is a lack of data on studies which have determined risk factors for sleep-related suffocation independently from unexplained infant deaths.
A team of researchers led by Dr Sharyn Parks Brown conducted a population-based case-control study using Centers for Disease Control and Prevention data (2016-2017). The researchers included Controls such as liveborn infants (Pregnancy Risk Assessment Monitoring System) and Sudden Unexpected Infant Death Case Registry cases. The risk factor prevalence and crude and adjusted odds ratios were calculated in the study.
The study included 112 sleep-related suffocation cases with 448 age-matched controls and 300 unexplained infant death cases with 1200 age-matched controls.
The study's results mentioned that the risk of sudden unexplained infant death increases with non-supine sleep, soft bedding use and surface sharing.
Adjusted odds for sleep-related suffocation ranged from 18.7 (infants not sharing a room with their mother or caregiver) to 1.9 (among infants with non-supine sleep positioning)
The researchers found that Adjusted odds for unexplained death ranged from 7.6 among infants not sharing a room with their mother or caregiver to 1.6 among non supine-positioned infants.
To conclude, the information provided in the study improves the message about safe infant sleep. The study confirmed unexplained death risk factors and estimated suffocation risk factors.
A 4-fold higher suffocation risk is tied to Nonapproved sleep surface use but is not associated with unexplained death. The use of soft bedding is strongly associated with suffocation.

Further reading:
Parks, S. E., DeSisto, C. L., Kortsmit, K., Bombard, J. M., & Shapiro-Mendoza, C. K. (2022). Risk Factors for Suffocation and Unexplained Causes of Infant Deaths. Pediatrics. https://doi.org/10.1542/peds.2022-057771