A new study by researchers with Kaiser Permanente Northern California suggests a simple strategy for reducing the risk of sudden death of infants in their sleep: turning on a fan at night.
The study's findings, based on data collected from nearly 500 mother-and-child pairs in California between 1997 and 2000, indicate that the use of a fan in an infant's room may reduce the likelihood of sudden death by 72%. But the data suggest that the protective effect applies mostly to babies in poor sleeping environments those who are put to bed in overheated rooms or on their stomach.
The National Institute of Child Health and Human Development (NICHD) issued a statement in response to the study, published Oct. 6 in the Archives of Pediatrics & Adolescent Medicine, warning that "that there is no substitute for the most effective means known to reduce the risk of [sudden infant death syndrome, or] SIDS: always placing infants for sleep on their backs."
The NICHD's federally funded "Back to Sleep" campaign, which advocates for putting babies to sleep face-up, has helped reduce the national SIDS death rate 56%, from 1.2 deaths per 1,000 live births in 1992 to .53 deaths per 1,000 live births in 2003. In addition to placing babies on their backs to sleep, pediatricians recommend that parents use firm mattresses for babies, avoid soft bedding such as comforters and quilts, put babies in their own cribs at night, keep infants from overheating and refrain from smoking during pregnancy and infancy.
Indeed, the study's authors say that caretakers who followed established safety guidelines were less likely overall to suffer the sudden death of a child, compared with those who tended not to take the same precautions. The study also found that when fans were used in the absence of other environmental risk factors that is, when parents already had other safeguards in place it had no significant additional impact on the risk of SIDS.
"If the baby was already in a good sleeping environment, there wasn't very much chance they were 'rebreathing,'" says Dr. De-Kun Li of Kaiser Permanente's Division of Research and a co-author of the study, referring to the re-inhalation of carbon dioxide that is associated with sudden unexplained death. "So it's not surprising that adding a fan, or not, didn't make that much difference."
The benefit of a fan became apparent, however, when it was used in sleep environments typically associated with a higher risk of SIDS. For example, researchers found that fans were associated with a 94% reduction in SIDS risk for babies who slept in rooms that exceeded 70 degrees F (21 degrees C); an 85% reduction for infants in rooms with closed windows; an 86% reduction among babies placed on their sides or stomach to sleep; and a 78% reduction among those who did not use a pacifier (the pacifier's handle is hypothesized to help maintain babies' breathing space under a blanket or in soft bedding).
"If you decrease the chance of rebreathing exhaled air, your SIDS rate is going to be reduced, says Li. "Using a fan is one way."
Betty McEntire, executive director of the American SIDS Institute, says the study is useful for underscoring the link between SIDS and rebreathing or overheating. "We know that increased carbon dioxide can hurt the baby's ability to arouse during sleep," says McEntire. "So you definitely want to prevent your baby from rebreathing and overheating."
"Chipping away at the SIDS problem is important," McEntire continues, "and this study adds a little bit [of clarity] to the puzzle."
The etiology of SIDS is still largely a mystery. To date, perhaps the best evidence of its cause comes from a 2006 study led by researchers at Children's Hospital Boston, who examined the brain tissue of babies who died from SIDS and those who died from other causes. Researchers found that SIDS babies often have a brain defect in a region of the brain that controls breathing, heart rate and blood pressure. The abnormality appears to weaken the responsiveness of certain functions, including arousal from sleep when the body fails to get enough oxygen. Researchers think the defect may be genetic in origin, although there are no biological tests yet to determine risk.
For now, the study's authors agree that the best way to reduce the likelihood of SIDS the leading cause of death among American infants aged under 1 year, which kills more than 2,000 infants each year is through environmental safety measures put forth by the American Academy of Pediatrics. Using a fan, Li says, "can provide concerned parents an extra measure to reduce SIDS."