Multiple Risk Factors Exist in Most Sudden Infant Death Syndrome Cases

A new study has identified that more than 96% of infants who died of sudden infant death syndrome (SIDS) were exposed to known risk factors, and that most of the cases contained multiple risk factors.

Researchers from Robert Wood Johnson Medical School (New Brunswick, NJ, USA) conducted a population-based retrospective review of 244 SIDS cases in the state of New Jersey (USA) between 1996 and 2000, and assessed the frequencies and cooccurrences of both modifiable (maternal and paternal smoking, nonsupine sleep or prone status at discovery, bed-sharing, or scene risks) and nonmodifiable (upper respiratory infection or gestational age of less than 37 weeks) risk factors.

The results showed that nonsupine sleep occurred in 70.4% of cases with data on position; thirteen cases were of infants who were discovered prone, which increased positional risk to 76.1% of the cases, in which 87% contained additional risks. Maternal smoking occurred in 42.6% of the cases with data on this risk, and 98% among those cases that had additional risks. At least one risk factor was found in 96% of the cases, and 78% had up to seven risk factors. Nine of the of 244 risk-free cases (3.7%), 7 lacked data; on the basis of the complete data, only 2 (0.8%) of all 244 cases were found to be risk free. When nonmodifiable risks were excluded, 5.3% of the cases met this definition. The study was published ahead of print on February 15, 2010, in the journal Pediatrics.

"Risk-reduction education of new parents and all other caregivers, such as grandparents and babysitters should be detailed,” said study coauthor Prof. Thomas Hegyi, M.D., of the department of pediatrics, who also serves as the medical director of the SIDS Center of New Jersey. "Parent's questions and concerns should be addressed thoroughly.”

SIDS is defined as a sudden and unexpected death of an infant before the first birthday that remains unexplained even after a comprehensive evaluation consisting of a complete autopsy, a death scene investigation, and a review of medical history of the infant and the family. Many studies now suggest that one of the potential causes may be an abnormality in the brainstem that would prevent an infant from responding to breathing challenges, such as those posed by prone sleep in soft bedding.

Guidance to parents regarding safe sleep practices should address the importance of sleeping on the back (the position associated with the lowest risk), but also should cover all other practices that have been identified as lowering the risk of SIDS, including, but not limited to, avoidance of exposure to tobacco smoke, elimination of the use of pillows, quilts, and soft or loose bedding in the infant's sleep environment, avoidance of any facial covering, and avoidance of the use of a shared sleep surface during sleep.

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