Secondhand smoke linked to SIDS
A new study linking secondhand smoke to sudden infant death syndrome is raising questions about whether parents should be held responsible for exposing their babies to tobacco-filled air.
Researchers at Toronto's Hospital for Sick Children and the University of Maryland found high levels of nicotine in the lung tissue of babies who died of sudden infant death syndrome, even in children whose parents said they did not smoke cigarettes in the house.
The findings are compelling enough that child-welfare agencies are considering whether they should take steps to protect children from inhaling tobacco smoke in the home.
"In light of this new research, we and other agencies will be looking at it and rethinking our position to see if a stronger position is more feasible," said Gail Vandermeulen, director of communications and quality assurance for the Ontario Association of Children's Aid Societies.
Previous studies, relying on reports parents supplied voluntarily, have for many years suggested the risk of SIDS increases with exposure to cigarette smoke, particularly during pregnancy.
But the new study, which uses a lab test, suggests that parents, perhaps feeling guilt or fearing litigation, may not provide accurate information about the air their babies breathe.
"It's biochemical proof that smoke is associated with SIDS," said Gideon Koren, lead investigator and senior scientist at the hospital's research institute. "Some parents may feel guilty, and probably we underestimate the contribution of smoking to the [risk] of SIDS."
In 9 of the 44 SIDS cases that researchers studied, for example, parents said they did not smoke. "But the lungs," Dr. Koren said, "told a different story.
"If Children's Aid Societies step in to protect children who are undernourished, maybe we have to step in when babies do not breathe clean air," said Dr. Koren, who also is a professor of pediatrics and pharmacology at the University of Toronto.
The study, published this month in the Journal of Pediatrics, does not find tobacco smoke actually causes SIDS, since at least three babies included in the research died of SIDS without nicotine in their lungs.
The biology behind the affliction, which kills up to 400 infants in Canada every year, remains a mystery, though many suspect the syndrome is linked to underdeveloped or malformed neural circuits in the brain that drive respiratory and cardiac function.
Dr. Koren said more research is needed to determine which of the toxic substances in tobacco smoke increases the risk. But babies, he said, are naturally more susceptible to environmental pollutants.
Adults inhale roughly 18 times a minute; babies inhale about 40 times a minute. And secondhand smoke has higher concentrations of substances such as nicotine and cyanide than mainstream smoke.
In 32 SIDS cases where the parents admitted smoking, autopsies found an average of 24 nanograms of nicotine per gram of lung tissue.
That was nearly twice the amount of nicotine found in the control group, which included babies who died of causes other than SIDS but whose parents also smoked.
The researchers are now trying to understand what those measurements equal in terms of number of cigarettes smoked.
Aurore CÃ´tÃ©, an associate professor of pediatrics at Montreal's McGill University and a scientific adviser to the Canadian Foundation of Sudden Infant Death, said the study's results are not at all surprising.
"If you ask parents about smoking they hide the truth," Dr. CÃ´tÃ© said. "But it is an addiction, and they need help to quit."
She predicted that parents quitting smoking could significantly lower the incidence of SIDS.
An international campaign to inform parents that they could reduce the risk of SIDS by having their babies sleep on their backs at all times, for example, reduced cases more than 30 per cent in the last 20 years.
"People don't smoke in their workplaces any more or their colleagues would kick them out, and yet people will smoke in their homes, around children," Dr. Koren said.
Ms. Vandermeulen of Children's Aid said attempts to curb smoking in the home have so far proved unworkable. In 1999, for example, the association drew up a policy trying to keep foster parents from smoking.
"It caused quite a controversy; people felt they had a right to do what they want to do in their own homes," Ms. Vandermeulen said. "So part of it is an enforcement issue: How do you monitor what people do in their living rooms?
"And if you see a parent smoking in front of their children how do you know if that's their first cigarette of the day, or the one-hundredth? Where do you draw the line?"