In a recent study, saliva revealed exposure to
tobacco smoke in roughly 80 percent of children brought to the
hospital for asthma or breathing problems. But only about a third of
parents said their children came in contact with smoke.
What's more, finding evidence of nicotine, a chemical in tobacco, in
children's saliva was a better predictor of whether they would need
to come back to the hospital, compared to the information parents
gave to doctors.
"We think saliva is a good and potentially useful test for assessing
an important trigger for asthma," Dr. Robert Kahn, the study's
senior author, told Reuters Health.
Previous research has found that being exposed to tobacco can lead
to airway problems and poor asthma control among children, Kahn and
his colleagues write in the journal Pediatrics.
By figuring out which children are being exposed to tobacco, doctors
may be able to step in and identify and possibly eliminate the
exposure, said Kahn, a pediatrician at Cincinnati Children's
Hospital Medical Center in Ohio.
For example, if a parent is still smoking cigarettes and exposing
the child to smoke, doctors can offer the parent smoking cessation
tools while the child is hospitalized.
For the new study, the researchers assessed data from 619 children
admitted to Cincinnati Children's Hospital Medical Center for asthma
or other breathing problems between August 2010 and October 2011.
The children were between one and 16 years old.
During the children's first couple of days in the hospital,
researchers asked their parents if the children had any exposure to
tobacco — either at home, in the car or in another place the
children slept. Nurses also collected blood and saliva samples from
About 35 percent of parents reported their children having some
However, about 56 percent of the children's blood samples and about
80 percent of their saliva samples tested positive for cotinine, a
component of nicotine that's a marker for tobacco exposure.
The difference in the results of the saliva and blood tests and the
parents' reports doesn't necessarily mean the parents lied about
their children's exposure to smoke.
It could also be that the researchers and doctors didn't ask enough
or the right questions or that the parents didn't know their
children were being exposed to smoke.
"Sometimes a parent's response to a simple question may not reflect
the nuances of life," Dr. James Kreindler said.
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He was not involved with the new study but is an attending
pulmonologist at The Children's Hospital of Philadelphia in
One in six children in the study had to be readmitted to the
hospital within a year.
Parents' reports of smoke exposure weren't tied to the likelihood of
children returning to the hospital. But Kahn and his colleagues did
find that children were more likely to be readmitted if their saliva
or blood tested positive for cotinine.
The researchers write that saliva is an attractive testing option,
because it's not hard or invasive to get a sample. It also appeared
to be a more sensitive test than blood.
But Kreindler cautioned that the new results don't mean children
should get tested for cotinine in the hospital.
"The test they are using to determine cotinine levels is a very
sophisticated test — not one that would be available to every
community hospital," he said. And the treatment for asthma wouldn't
necessarily change based on whether a child was exposed to tobacco,
Kreindler said a cost analysis would also be needed to look at the
expense of testing.
According to Kahn, a cost analysis would most likely follow a trial
of whether smoking cessation after positive saliva tests decreased
hospital readmissions among children.
"The take-home message should always be that exposure to secondhand
smoke for both adults and children is a significant health risk
factor — particularly for children with asthma and respiratory
disorders," Kreindler said. "They should not be exposed to
secondhand smoke under any circumstance."
online Jan. 20, 2014.
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