Sleep Environment and the Risk of Sudden Infant Death Syndrome in an Urban Population: The Chicago Infant Mortality Study
Study by F. R. Hauck, S. M. Herman, M. Donovan, S. Iyasu, C. Merrick Moore, E. Donoghue, R. H. Kirschner and M. Willinger
Case-Control Study · Pediatrics (Vol. 111, Issue 5, Part 2, pp. 1207-1214) · DOI: 10.1542/peds.111.S1.1207
Key Takeaway
Soft Sleep Surfaces Were Linked to Much Higher Odds of SIDS
What was tested: Researchers compared 260 infants who died of sudden infant death syndrome (SIDS) in Chicago from 1993 to 1996 with 260 matched living infants, looking at how and where each baby last slept (Hauck et al., 2003).
What the numbers showed: A soft sleep surface was linked to about 5 times the odds of SIDS (odds ratio 5.1, before adjusting for other factors). Pillow use, sleeping face down and some types of bed sharing were also linked to higher odds. Soft surface stayed significant after adjusting for other factors.
What this means for you: Put babies to sleep on their back on a firm, flat surface with no pillows or soft bedding. This is also what the American Academy of Pediatrics recommends.
Key Numbers
How the Study Was Done
This population-based case-control study looked at 260 SIDS deaths in Chicago between 1993 and 1996 and an equal number of matched living infants. The researchers compared the babies' sleep environment at their last sleep and other parts of infant care (Hauck et al., 2003).
A case-control study compares babies who died with similar babies who did not, to see which factors were more common among the deaths. It can show strong links, but it cannot prove on its own that one factor caused a death. The study aimed to help reduce SIDS among Black infants, who were affected at twice the rate of white infants.
What the Study Compared
Firm Sleep Surface
The comparison. Babies placed on a firm surface had lower odds of SIDS than babies placed on a soft one.
Soft Sleep Surface
About 5 times the odds of SIDS (unadjusted odds ratio 5.1, 95% confidence interval 3.1 to 8.3). Still significant after adjustment.
What the Study Found
Several parts of the last sleep were linked to higher odds of SIDS: a soft surface (odds ratio 5.1, 95% confidence interval 3.1 to 8.3), sleeping face down (2.4), pillow use (2.5), the face or head covered with bedding (2.5) and bed sharing (2.7 overall). These are unadjusted odds ratios. Pacifier use and breastfeeding were linked to lower odds (Hauck et al., 2003).
When the factors were analysed together, sleeping face down, a soft surface, pillow use, bed sharing other than with parents alone, and not using a pacifier remained significant. The study was supported by grants from the National Institute of Child Health and Human Development and the CDC.
The American Academy of Pediatrics recommends placing babies on their back on a firm, noninclined sleep surface, room sharing without bed sharing, and avoiding soft bedding and overheating (Moon et al., AAP 2022). An earlier version of this page cited a 2014 study whose DOI belongs to an unrelated paper. We could not find that study, so its figures have been removed.
How to Apply This Study When Choosing a Mattress
What to look for: A firm, flat crib mattress that fits the crib, with a fitted sheet and nothing else.
Do not add pillows, bumpers, soft toppers or loose bedding. This study did not test any crib mattress brand, so check that any mattress you buy is made for cribs and fits snugly.
Study Scope and Limitations
One city, deaths from 1993 to 1996, and a case-control design that shows links rather than proof of cause. The headline odds ratios are before adjustment. No crib mattress brand was tested.
Primary Citation
Hauck, F. R., Herman, S. M., Donovan, M., Iyasu, S., Merrick Moore, C., Donoghue, E., Kirschner, R. H., & Willinger, M. (2003). Sleep environment and the risk of sudden infant death syndrome in an urban population: The Chicago Infant Mortality Study. Pediatrics, 111(5 Pt 2), 1207-1214. https://doi.org/10.1542/peds.111.S1.1207