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New SIDS Research

African American baby sleeping on his back It is sudden, without warning and deadly. Sudden Infant Death Syndrome (SIDS) claims the lives of approximately 100 children in North Carolina every year. It is the leading cause of death among infants one month to one year old. While we know the risk of SIDS can be reduced, there is much about it that remains a mystery, but new research offers some promising clues into the cause of SIDS.

In an article published in the February 3, 2010 issue of the Journal of the American Medical Association (JAMA), Harvard researchers report that babies who die of SIDS may have low levels of serotonin, a brain chemical involved in regulating breathing and other vital functions. According to the study, tissue samples from infants who died of SIDS showed a serotonin level in the brain that was 26 percent lower than those infants who died of other causes. They also had lower levels of an enzyme involved in synthesizing serotonin. The researchers say this discovery brings them a step closer to understanding why babies who appear to be perfectly healthy might die suddenly, and that it could eventually lead to the development of a screening test to identify at-risk infants.


Most deaths due to SIDS occur between two and four months of age, and increase during cold weather months. We also know African-American infants are twice as likely and Native Americans three times more likely to die of SIDS than Caucasian infants. Many researchers believe there is no single risk factor likely to cause a SIDS death; rather there are several combined risk factors. In fact, it is thought that SIDS results from a simultaneous occurrence of an underlying vulnerability, a critical developmental period and an environmental stressor. This is called the “Triple Risk Model”.

The JAMA study found that 95% of SIDS cases had one or more risk factors and 88% had two or more. Ninety-three percent has at least one extrinsic (environmental) factor—49% stomach sleeping, 14% side sleeping, 37% face down, 20% bed sharing and 44% had a trivial illness prior to death.

While this new study is promising in suggesting a possible biological cause of SIDS, it does not alter the need to remain vigilant in educating new parents and caregivers about the importance of safe sleep positioning. The American Academy of Pediatrics recommends back sleeping as the only acceptable sleep position for babies under one Caucasian baby sleeping on his backyear of age. Putting babies to sleep on their stomach increases the risk for SIDS. Some researchers believe it puts pressure on a child’s jaw and narrows the airway which hampers breathing. Another theory suggests that a face down position increases an infant’s risk of “rebreathing” his or her own exhaled air, particularly if the baby is sleeping on a soft mattress or with excessive bedding, stuffed toys, or a pillow near their face. This could cause carbon dioxide to accumulate depriving the baby of oxygen.

Reducing the Risk

In addition to placing infants on their backs to sleep there are several other simple steps parents and caregivers can take to help reduce the risk of SIDS:

North Carolina's Safe Sleep Initiative

For fifteen years, the North Carolina Healthy Start Foundation has lead the way in educating parents about infant safe sleep positioning resulting in a reduction of SIDS rates in our state. Although SIDS rates in North Carolina have decreased significantly over the past 10 years, they continue to exceed the national average and progress seems to have leveled off. As part of its infant safe sleep initiative the Foundation has a variety of outreach and training programs:

North Carolina Healthy Start Foundation

The North Carolina Healthy Start Foundation was established in 1990 with a five year, $5 million pledge from Glaxo, Inc. for the purpose of providing leadership in the state's effort to reduce North Carolina's unacceptably high infant mortality rate. Since its inception, the Foundation has grown into a nationally recognized, private, nonprofit organization dedicated to reducing infant death and illness and to improving the health of women and young children in North Carolina. As the Foundation celebrates its 20th anniversary we pledge to continue to work tirelessly to improve the health of our state’s citizens.

Web site link:

At A Glance
  • In 2008, the number of infant deaths related to Sudden Infant Death Syndrome, (SIDS) increased, accounting for 136 deaths in children under one year of age
  • In N.C. back to sleep position placement for infants is more prevalent among Whites, Hispanics, mothers of older age and mothers of higher education
  • 48% of N.C. African-Americans reported putting babies to sleep on the back compared to 74% of Whites (non-Hispanic) and 68% of Hispanics
  • N.C. babies exposed to secondhand smoke were more likely to be placed on their stomach (24%) than babies not exposed to cigarette smoke (15%)

Source: N.C. Center for Health Statistics


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