Study Identifies SIDS Risk Factors Among American Indian Infants

A study of Northern Plains Indians found that infants were less likely to die of Sudden Infant Death Syndrome (SIDS) if their mothers received visits from public health nurses before and after giving birth.

The Aberdeen Area Infant Mortality Study, appearing in the December 4 Journal of the American Medical Association, also found that binge drinking (five or more drinks at a time) during the mother's first trimester of pregnancy made it eight times more likely that her infant would die of SIDS. Any maternal alcohol use during the periconceptional period (three months before pregnancy or during the first trimester) was associated with a six-fold increased risk of SIDS. The study also found that infants were more likely to die of SIDS if they wore two or more layers of clothing while they slept.

"This study has identified important risk and protective factors for SIDS among this group of American Indians," said Solomon Iyasu, MBBS, MPH, an epidemiologist with the reproductive health program at the CDC, and lead author of the study. "Strengthening public health nurse visiting programs and programs to reduce alcohol consumption among women of childbearing age could potentially reduce the high rate of SIDS."

The Aberdeen study was funded by three agencies of the Department of Health and Human Services: the Indian Health Service (IHS), the National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health, and the Centers for Disease Control and Prevention (CDC). The study was carried out by a consortium of researchers at the Aberdeen Area of the Indian Health Service, the NICHD, the CDC, Boston Children's Hospital, Harvard Medical School, and the Massachusetts SIDS Center.

The study analyzed 33 SIDS infant deaths between 1992 and 1996 and 66 control infants, who were matched for postnatal age and community of residence.

Infants in homes where a public health nurse had visited before or after birth were 80 percent less likely to die from SIDS than babies in homes that never had such visits - but the study's authors were unable to draw a conclusion about what aspects of the nurse's visit helped. The IHS currently recommends that public health nurses make one prenatal home visit and visits at one and six weeks postpartum.

"The proportion of women who drank in the study declined markedly after the first trimester-indicating that the majority of women stopped drinking once they learned they were pregnant," said Dr. Marian Willinger, Ph.D, Special Assistant for SIDS at NICHD and a study author. "However, there is a risk for SIDS associated with maternal drinking in the period when women may not know they are pregnant."

Wearing two or more layers of clothing (not including a diaper) increased a baby's risk for SIDS more than six-fold, the researchers found. This is consistent with other studies showing that excess thermal insulation for a specific room temperature was associated with increased SIDS risk.

"Parents should dress their babies lightly for sleep and maintain a comfortable room temperature. Overdressing them can result in potentially dangerous overheating", said Leslie Randall, RN, MPH, an epidemiologist with CDC, member of the Nez Perce Tribe, and co-Principal Investigator for the Aberdeen Area Infant Mortality Study while at IHS.

The rate of SIDS among American Indians is the highest of any population group and was slightly more than double that of whites in 1999 - 1.5 SIDS deaths per 1,000 live births compared with 0.7 per 1,000. The rate of SIDS in the Aberdeen Area of the Indian Health Service, which serves reservations in North and South Dakota, Nebraska and Iowa, is the highest of all of the 12 IHS regions. During 1996 to1998, the most recent data on infants available from the AAIHS, the rate of SIDS was 3.5 deaths for every 1,000 live births.

The Aberdeen Area Tribal Chairman's Health Board assisted in the study's design and implementation. Parents willingly participated in the study and were interviewed by American Indian nurses to help identify factors that contribute to the high rates of SIDS in their communities. Nine tribes and one urban American Indian community participated in the study.

The HHS-supported Back to Sleep Campaign recommends that all infants be placed on their backs for sleep to reduce the risk of SIDS. Visit for more information.


For additional information about the CDC, visit their website at:; about the IHS, visit their website at:; and about NICHD, visit their website at:

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