Suffocation and unexplained infant death risks differentially affected by safe sleep practices

by Matthew Dawson, MD; Alex Gipsman, MD

Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. A case-control study utilizing publically available databases of sudden infant deaths and infant/maternal behaviors identified differential risk factors for sleep-related suffocation death and sudden unexplained infant deaths.

2. All five studied sleep variables (position, soft bedding use, sleep surface, room sharing, sleep surface sharing) had notable differences in the odds ratios of sleep-related suffocation versus unexplained infant death.

Evidence Rating Level: 3 (Average)

Study Rundown:

The sporadic occurrence and lack of witnesses to sudden infant death syndrome (SIDS) or sleep-related suffocation deaths make it challenging to design preventative health strategies. To address this deficit, a case-control study was designed using publically available databases of infant/maternal demographic and behavioral data. Cases were collected from the Center for Disease Control’s Sudden Unexpected Infant Death Case Registry (SUID) and split into suffocation deaths (those with on-scene evidence of airway obstruction or thoracic compression) and unexplained infant deaths (those that, despite a thorough forensic and medical examination, had no identifiable cause of mortality). Controls were selected from a representative pseudo-population generated from a state-run self-reporting system for peri-pregnancy and infant health behaviors. Two separate case-control analyses were conducted, one each for suffocation deaths and sudden unexplained deaths. Demographically, male infants, Black infants, and infants under Medicaid were at statistically significantly higher risk for both sleep-related suffocation and unexplained infant deaths when compared to white infants, while Hispanic infants were shown to be at increased risk only for unexplained infant death. Both soft bedding use and lack of caregiver room sharing dramatically increased the risk of suffocation, with a more moderate increase in the risk of sudden death. Appropriate supine sleep position, meanwhile, had no significant effect on suffocation risk but decreased the risk of sudden unexplained death. As with many studies of SIDS and related infant mortalities, this study is limited by a lack of national standards for reporting sudden infant death, further compounded by this study’s reliance on generating a control sample from a database of primarily self-reported behaviors. However, the deliberate design separating suffocation deaths and otherwise unexplained deaths allows for a more nuanced examination of demographic and behavioral risk factors, possibly allowing for a targeted design of safe sleep education for new parents.

In-Depth [case-control study]:

This study was a population-based case-control study utilizing publicly available databases to assess the risk factors for sudden unexplained infant deaths and sleep-related suffocation. Cases of sudden unexplained infant death from 2-9 months of age in 2016 and 2017 were identified from the CDC’s SUID Case Registry. A pseudopopulation of controls, utilizing representative data from statewide PRAMS self-reporting surveillance systems, was generated for all states with >55% response to the PRAMS surveys. Four controls for each case were randomly selected from this pseudopopulation, resulting in two groups for analysis: 112 cases of sleep-related suffocation with 448 age-matched controls and 300 unexplained infant deaths with 1200 controls. These two populations were independently assessed for multiple demographic variables and five infant sleep practices (position, soft bedding use, sleep surface type, sleep surface sharing, and caregiver room sharing). Crude exposure odds ratios and adjusted odds ratios were calculated, with the recommended sleep practice used as the reference variable. Demographically, males were at greater risk for sleep-related suffocation and unexplained infant death (OR 1.9, 95% CI 1.3-3.0 and 1.6, 1.2-2.1), as were black infants (5.1, 3.1-8.5 for suffocation, 5.1, 3.7-6.9 for unexplained death). Hispanic infants had no significant increase in suffocation risk (1.7, 0.9-3.3) although they did have a mild increase in unexplained infant death (1.7, 1.1-2.5). The strongest effects in sleep behavior-associated risk factors were seen in soft bedding use and lack of room sharing on sleep-related suffocation risk (16.3, 5.0-53.3 and 18.7, 6.8-51.3 respectively); both variables had more moderate effects on the risk of sudden unexplained infant death (5.0, 3.2-8.0 and 7.6, 4.7-12.2).

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