Elsevier

The Journal of Pediatrics

Volume 149, Issue 5, November 2006, Pages 630-633.e1
The Journal of Pediatrics

Original article
Sudden infant death syndrome: Risk factors for infants found face down differ from other SIDS cases

https://doi.org/10.1016/j.jpeds.2006.07.041Get rights and content

Objective

To test the hypothesis that infants with sudden infant death syndrome (SIDS) found face down (FD) would have SIDS risk factors different from those found in other positions (non–face-down position, NFD).

Study design

We used the New Zealand Cot Death Study data, a 3-year, nationwide (1987 to 1990), case-control study. Odds ratios (univariate and multivariate) for FD (n = 154) and NFD SIDS (n = 239) were estimated separately, and statistical differences between the two groups were assessed.

Results

Of 12 risk factors for SIDS, there were 8 with a statistically significant difference between FD and NFD infants. After adjustment for the potential confounders, younger infant age, Maori ethnicity, low birth weight, prone sleep position, use of a sheepskin, and pillow use were all associated with a greater risk of SIDS in the FD than the NFD group. Sleeping during the nighttime, maternal smoking, and bed-sharing were associated with a risk of SIDS only in the NFD group. Pacifier use was associated with a decreased risk for SIDS only in the NFD group, whereas being found with the head covered was associated with a decreased risk for SIDS for the FD group.

Conclusions

Infants with SIDS in the FD position appear to be a distinct subgroup of SIDS. These differences in risk factors provide clues to mechanisms of death in both SIDS subtypes.

Section snippets

Methods

The New Zealand Cot Death Study has been described previously.6, 7 This was a large, multicenter, case-control study of infants who died of SIDS between 28 days of age and completion of their first year of life (postneonatal deaths) in the period November 1, 1998, to October 31, 1990. A standard definition for SIDS was used.8 Most of the data collected preceded the SIDS prevention campaign. There were 716 postneonatal deaths, of which 485 were classified as SIDS. Obstetric records were examined

Results

Risk factors that showed an interaction between FD and NFD SIDS at the univariate level are shown in the Table (available at www.jpeds.com). An interaction means that there was a statistically significant difference in the magnitude of the odds ratios between the FD and NFD groups. After adjustment for potential confounders in the model, all but age of the mother at pregnancy remained significantly different between the FD and NFD groups. Younger infant age, Maori ethnicity, low birth weight,

Discussion

In this study, risk factors for SIDS differ markedly between infants found dead FD and those found dead in other positions. The findings provide new insights into the pathophysiology of SIDS. The group of infants found FD are uniquely associated with risk factors closely linked to causal theories derived from physiological data. The increased risk of SIDS with the use of pillows and sheepskins are only seen with FD SIDS. These are items of bedding likely to be placed beneath an infant’s head

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    The New Zealand Cot Death Study was supported by the Medical Research Council of New Zealand and Hawkes Bay Medical Research foundation. Professor Ed Mitchell and Dr John Thompson are supported in part by the Child Health Research Foundation. This research is supported by Grant HD 10993.

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