Safe Infant Sleep: Landmark Articles That Contributed to the Decline in SIDS and Other Sleep-Related Infant Deaths

Commentary From the AAP Task Force on SIDS

 The AAP Task Force on SIDS was convened by the American Academy of Pediatrics (AAP) in 1990. This group of experts in the field of sudden and unexpected infant death continues to review the literature to develop and revise the AAP safe sleep recommendations.

The Task Force reviewed more than 250 excellent Pediatrics publications that have all contributed to our knowledge of SIDS and other sleep-related infant deaths and has selected 5 landmark studies. We believe that these selected studies were instrumental to the initial US Back to Sleep campaign and its successor, the current Safe to Sleep campaign, which were associated with a 50% reduction in deaths. In addition, these studies provide the evidence base for many of the AAP safe sleep recommendations that have reshaped the anticipatory guidance and advocacy efforts of pediatricians and other clinicians caring for infants worldwide.

Safe Infant Sleep: Landmark Articles That Contributed to the Decline in SIDS and Other Sleep-Related Infant Deaths

Rachel Y. Moon, MD¹, Elie G. Abu Jawdeh, MD, PhD², Elizabeth A. Bundock, MD, PhD³, Rebecca F. Carlin, MD⁴, Jeffrey D. Colvin, MD, JD⁵, Fern R. Hauck, MD, MS⁶, Sunah S. Hwang, MD, PhD⁷

Affiliations: ¹Department of Pediatrics, University of Virginia School of Medicine; ²Department of Pediatrics/Neonatology, College of Medicine, University of Kentucky; ³Office of Chief Medical Examiner - Vermont State Department of Health; ⁴Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons; ⁵Department of Pediatrics, Children's Mercy Kansas City and School of Medicine, University of Missouri-Kansas City; ⁶Department of Family Medicine and Department of Public Health Sciences, University of Virginia School of Medicine; ⁷Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine

Highlighted Articles From Pediatrics

• Schoendorf KC, Kiely JL. Relationship of sudden infant death syndrome to maternal smoking during and after pregnancy. Pediatrics. 1992;90:905-908
• Mitchell EA, Tuohy PG, Brunt JM, et al. Risk factors for sudden infant death syndrome following the prevention campaign in New Zealand: A prospective study. Pediatrics. 1997;100:835-840
• Gershon NB, Moon RY. Infant sleep position in licensed child care centers. Pediatrics. 1997;100:75-78
• Hauck FR, Herman SM, Donovan M, et al. Sleep environment and the risk of sudden infant death syndrome in an urban population: The Chicago Infant Mortality Study. Pediatrics. 2003;111(Supplement 1):1207-1214
• Shapiro-Mendoza CK, Kimball M, Tomashek KM, Anderson RN, Blanding S. US infant mortality trends attributable to accidental suffocation and strangulation in bed from 1984 through 2004: Are rates increasing? Pediatrics. 2009;123:533-539

In the late 1980s, several reports from Europe, Australia, and New Zealand suggested an association between infant prone (stomach) sleeping and sudden infant death syndrome (SIDS). In 1990, the American Academy of Pediatrics (AAP) convened the Task Force on SIDS to review the literature and make a limited recommendation on whether US pediatricians and other clinicians should recommend that infants not sleep prone. The task force, led by John Kattwinkel, MD, found the evidence to be convincing, and in 1992, published the first SIDS policy statement entitled “Positioning and SIDS” that recommended that “healthy infants, when being put down for sleep, be positioned on their side or back.”¹

Since 1992, the AAP has continued to rely on the Task Force, a group of clinicians and researchers, to provide guidance on infant safe sleep. Pediatrics published the most recent recommendations,² along with the supporting evidence base,³ in June 2022.

As a task force, we are pleased to participate in the celebration of the 75^th anniversary of Pediatrics and congratulate the AAP on this important achievement. We have selected 5 articles published in Pediatrics that, in our opinion, have been the basis of national—and, indeed, global—risk reduction efforts to prevent all sleep-related infant deaths (encompassing SIDS, accidental suffocation and strangulation in bed [or other sleep surface], and ill-defined deaths). All 5 papers are epidemiologic studies. Although physiology, pathology, and genetic research all provide key insights that help us to understand the mechanism(s) by which infants die suddenly and unexpectedly in a sleep environment, epidemiologic studies have provided the cornerstone for risk reduction efforts. In particular, large case-control and population-based epidemiologic cohort studies have compiled data on a broad array of infant, family, and community characteristics that have identified risk factors, particularly those that are modifiable, associated with sleep-related infant death.

In the early 1990s, most high-income countries launched public awareness campaigns, such as the US Back to Sleep campaign, to encourage caregivers not to place infants prone. It is important to monitor trends even after such a campaign is launched, not only to assess changes in the rates of infant deaths, but also to identify new risks that may not have been evident before. The New Zealand Cot Death Study, a nationwide case-control study that has collected data since 1987, did exactly that, and Mitchell’s 1997 paper, “Risk Factors for Sudden Infant Death Syndrome Following the Prevention Campaign in New Zealand: A Prospective Study,”⁴ was one of the first studies to identify side position as a new risk factor. Subsequent studies have shown that the risk of sleeping in the side position is statistically similar to the risk of sleeping in the prone position. Mitchell et al also identified in utero smoke exposure and bed sharing, the latter particularly in combination with in utero and postpartum smoke exposure, to be important risk factors.

The 1992 study by Schoendorf and Kiely entitled “Relationship of Sudden Infant Death Syndrome to Maternal Smoking During and After Pregnancy,”⁵ based on a large US national database, was an early study that demonstrated the independent risk of passive smoke exposure during infancy on SIDS and documented a higher risk of combined prenatal and postpartum maternal smoking. This provided further evidence to encourage smoking cessation among pregnant persons and families with children. These findings have been confirmed by multiple studies, and a recent study estimated that 22% of US sudden and unexpected infant deaths can be directly attributed to exposure to smoking.⁶

The Back to Sleep campaign was initially directed toward parents and family members. However, nearly half of US infants and toddlers spend part of their day in child care settings. In 1997, Naomi Gershon and Rachel Moon, MD, surveyed licensed child care providers in the metropolitan Washington, DC, area and found that 50% were placing infants prone for sleep.⁷ This disturbing finding led to nationwide advocacy efforts to implement safe sleep regulations in child care settings. As a result of these efforts, child care centers in all states and the District of Columbia (and family child care homes in all but 3 states) now require infants to be placed supine for sleep. In addition, most states now have child care regulations about crib safety that prohibit soft bedding in sleep environments.

Important disparities remain in the rates of sudden unexpected infant death, with infants from minority or poorly resourced communities dying at higher rates. In 2003, Fern Hauck, MD, MS, and colleagues published results from the Chicago Infant Mortality Study, the largest case-control study in the US. “Sleep environment and the risk of sudden infant death syndrome in an urban population: The Chicago Infant Mortality Study”⁸ described risk factors in a largely minority population. Importantly, they identified that soft bedding in the infant sleep environment and sleeping on a sleep surface with an infant, especially when the sleeping person is not a parent, greatly increase the odds of sudden and unexpected infant death. They also found that both pacifier use and breastfeeding confer protection against these deaths.

Although the rates of SIDS continue to decline, the rates of sleep-related infant death overall have not declined in more than 20 years. Many deaths that would have previously been categorized as SIDS are now attributed to accidental suffocation and strangulation in bed (or other sleep surface). Carrie Shapiro-Mendoza, PhD, and colleagues at the Centers for Disease Control and Prevention published “US infant mortality trends attributable to accidental suffocation and strangulation in bed from 1984 through 2004: Are rates increasing?” in 2009.⁹ This paper confirmed that there had indeed been a diagnostic shift, and that infant mortality rates attributed to accidental suffocation and strangulation in bed quadrupled between 1984 and 2004. They described the importance of a safe sleep environment to avoid overlay, suffocation by bedding, and wedging/entrapment. They too emphasized the danger of sharing the bed, couch, or other surface with an infant, finding that more than half of deaths occurred in that setting.

It is discouraging that rates of sleep-related infant deaths remain stubbornly high, and the persistent disparities in sleep-related infant death are unacceptable. We now recognize that structural racism and the social determinants of health are important root causes of a substantial proportion of these deaths. As a result, our future research must not only examine individual-level factors. It must also examine community- and structural-level factors, and evaluate the impact of interventions within communities and advocacy efforts at the local, state, and federal levels. Without this renewed, broader research agenda, we will not have the knowledge base to remedy the systemic factors that perpetuate these tragic deaths and health inequities. 

References

1. Kattwinkel J, Brooks J, Myerberg D, AAP Task Force on Infant Positioning and SIDS. Positioning and SIDS [published erratum appears in 1992; 90(2):264]. Pediatrics. 1992;89(6):1120-1126
2. Moon RY, Carlin RF, Hand I, Task Force on Sudden Infant Death Syndrome, Committee on Fetus and Newborn. Sleep-related infant deaths: Updated 2022 recommendations for reducing infant deaths in the sleep environment. Pediatrics. 2022;150(1):e2022057990; doi: 10.1542/peds.2022-057990
3. Moon RY, Carlin RF, Hand I, Task Force on Sudden Infant Death Syndrome, Committee on Fetus and Newborn. Evidence base for 2022 updated recommendations for a safe infant sleeping environment to reduce the risk of sleep-related infant deaths. Pediatrics. 2022;150(1):e2022057991; doi: 10.1542/peds.2022-057991
4. Mitchell EA, Tuohy PG, Brunt JM, et al. Risk factors for sudden infant death syndrome following the prevention campaign in New Zealand: A prospective study. Pediatrics. 1997;100(5):835-840
5. Schoendorf KC, Kiely JL. Relationship of sudden infant death syndrome to maternal smoking during and after pregnancy. Pediatrics. 1992;90(6):905-908
6. Anderson TM, Lavista Ferres JM, Ren SY, et al. Maternal smoking before and during pregnancy and the risk of sudden unexpected infant death. Pediatrics. 2019;143(4):e20183325; doi: 10.1542/peds.2018-3325
7. Gershon NB, Moon RY. Infant sleep position in licensed child care centers. Pediatrics. 1997;100(1):75-78
8. Hauck FR, Herman SM, Donovan M, et al. Sleep environment and the risk of sudden infant death syndrome in an urban population: The Chicago Infant Mortality Study. Pediatrics. 2003;111(Supplement 1):1207-1214
9. Shapiro-Mendoza CK, Kimball M, Tomashek KM, Anderson RN, Blanding S. US infant mortality trends attributable to accidental suffocation and strangulation in bed from 1984 through 2004: Are rates increasing? Pediatrics. 2009;123(2):533-539; doi: 10.1542/peds.2007-3746