Objective: To investigate whether infants who died of sudden infant death syndrome (SIDS) were routinely placed in different sleep positions compared with healthy infants in a multiethnic diverse population in the United States.
Design: A population-based case-control study.
Setting: Five counties in Southern California including Los Angeles, Orange, San Bernardino, Riverside, and San Diego.
Participants: Parents of 200 white, African-American, Hispanic, and Asian infants who died of SIDS between January 1989 and December 1992 and parents of 200 healthy, living infants matched on the basis of birth hospital, birth date, race, and gender. Information was obtained from detailed telephone interviews with the parents and validated with obstetric and pediatric records.
Main outcome measures: Routine sleep position, type of bedding, and objects in bed were determined for both case and control infants, while the last-placed and found sleep and face positions at death were reported for SIDS infants.
Results: Approximately 66% of SIDS infants and 64% of comparison infants routinely slept on their abdomens (P = .91). At the time of death, 80% of cases were found sleeping on their abdomens. There was no difference in routine sleep position for SIDS infants and comparison infants (odds ratio = 0.76; 95% confidence interval, 0.42 to 1.38), while simultaneously adjusting for birth weight (in grams), medical conditions at birth, breast-feeding, passive smoking, maternal recreational drug use, prenatal care, and infant vomiting. Hispanic parents routinely placed their infants on their abdomens less frequently than white parents (P < .01). However, the prone sleep position (face down) was the most commonly found sleep position at death in both Hispanic and non-Hispanic infants.
Conclusions: Routine prone sleep position was not associated with an increased risk of SIDS in this study population. The results need to be confirmed with other parents of SIDS infants interviewed before the height of publicity regarding prone sleep position in the United States.