Having babies sleep on their backs apparently lowered the rate of sudden infant death syndrome, but fans may also help them live through the night, according to a new study.

The trend of having babies go "back to sleep" -- that is, sleeping face up -- coincided with a 56 percent drop in SIDS from 1992 to 2003, according to the report. Since then, the rate has leveled off.

In order to eliminate more cases, researchers looked for other changes that might help babies.

Kimberly Coleman-Phox of Kaiser Permanente talked to the mothers of 185 mothers whose children died of SIDS and 312 mothers of randomly selected infants who were asked about the last time their babies had slept.

Having a fan on was seen as lowering the death risk 72 percent. In a room over 69 degrees, it lowered the risk 94 percent.

She confirmed that side and stomach sleeping was more common in the babies who died.

She also found that 96 percent of those who died were not using a pacifier, compared to 76 percent of the others. Deaths were also more common in babies who slept on a soft surface or slept with someone other than a parent.

The study appears in the October issue of Archives of Pediatrics & Adolescent Medicine.