Putting a fan in the room with sleeping babies may help decrease the risk of sudden infant death syndrome in warm temperatures or other poor sleep environments, according to a study.

Fan use during sleep was linked to a 72 percent decrease in SIDS risk. The reduction in death risk was greater for babies sleeping in a warm environment than for those in rooms with closed windows, sharing a bed with someone other than a parent, lying on their sides or in a prone position, or not using a pacifier. The findings were released today in the Archives of Pediatric & Adolescent Medicine.

SIDS, caused by an infant's rebreathing exhaled air, is the leading cause of deaths in the U.S. for infants at ages 1 month to 1 year. The SIDS rate declined from 1992 to 2003, the latest year for which the study cited data, as more parents and caretakers place infants on their backs and on hard surfaces to reduce the hazard.

"If you have a little trapping of carbon dioxide, the increased ventilation can help the air movement and dissipate this trapping of carbon dioxide and reduce risk associated with rebreathing," said study coauthor De-Kun Li, a scientist at the Division of Research of the Kaiser Permanente health maintenance organization, in Oakland, California. "This new knowledge gives parents an additional measure if the parent wants to take it to reduce the risk of SIDS."

Death Risk Dropped

The study was conducted from 1997 to 2000. It included mothers of 185 infants who died from SIDS and 312 randomly selected infants, matched on county, maternal ethnicity and age, from 11 counties in California. Fan use in a warmer room was linked to a 94 percent reduction in SIDS risk. In a room with cooler temperatures, the association was less strong and no longer significant, the study said.

Fan use appeared to decrease the SIDS risk when infants shared a bed with someone other than a parent, slept in a room with a window closed, slept without a pacifier, or were placed in a side or prone position. Fan use in those conditions didn't appear to lower the SIDS risk significantly, as was in case with warm temperatures, according to the study.

The SIDS rate declined 56 percent from the 1992 level to 0.53 deaths per 1,000 infants in 2003.

Babies Sleep Prone

Almost 25 percent of infant-care providers don't place infants on their backs, and the prone, or face-down sleeping position, is more common when care providers are young, black or have low income or education levels, the study said. Fans were used with the same frequency in all study groups, and that could help reduce SIDS risk for infants in adverse sleeping environments, the study found.

"Maybe for those people who are putting their baby to sleep on their stomach, maybe they don't have any resistance accepting using a fan," Li said.

The fan-use study "needs to be confirmed by further research," said Marian Willinger, special assistant for SIDS Research at the Eunice Kennedy Shriver National Institute of Child Health and Human Development, in an e-mail statement. "It cannot be emphasized strongly enough, however, that there is no substitute for the most effective means known to reduce the risk of SIDS: always placing infants for sleep on their backs."

Li said fans that while fans may be an additional precaution for parents, they shouldn't be used in place of other prevention methods.