Exposure to tobacco smoke is a much bigger risk factor for sudden infant death syndrome than was previously suspected, and keeping newborns away from tobacco smoke could reduce the death rate from SIDS by nearly two-thirds, British researchers reported Friday.
In the largest study of its kind, encompassing more than 350,000 births during a two-year period, the team also found that allowing an infant to sleep on its side doubles the risk of death compared to sleeping on its back, a previously unsuspected finding.
As many as one-third of parents in England have adopted side-sleeping as a compromise because of the high risk of SIDS previously linked to sleeping face down, according to the study. Sleeping on the side reduces the risk of SIDS, but not as much as sleeping on their backs, the researchers said.
Reporting in the British Medical Journal, the team said that in addition to being kept away from tobacco smoke, if infants were also placed on their backs to sleep and wrapped only in light blankets, the SIDS death rate in England could be reduced to less than one-quarter of what it is today.
The reduction would be even higher in the United States where many infants still sleep on their stomachs, said Dr. Peter Fleming of the University of Bristol, who headed the study.
With efforts being made to control infant sleep positions in the United States, smoking is becoming the next concern that needs to be addressed, said neurobiologist Marian Willinger of the National Institute of Child Health and Human Development.
For every hour spent each day in a room where people smoke, the risk increases 100 percent, Fleming said. If an infant spends four hours per day in such a room, he or she is four times as likely to die of SIDS as a child not exposed to tobacco smoke.
Researcher also found an equally large risk was associated with wrapping the children heavily or using heavy comforters, which allow the children to overheat. Parents should place infants in a "feet-to-foot" position, with their feet against the bottom of the bed, so they cannot slip down under the covers, he said.