Asking parents about asthmatic children's smoke exposure may not yield the most reliable information, researchers said.
According to a recent study, in roughly 80 percent of children brought to the hospital for asthma or breathing problems, saliva revealed exposure to tobacco smoke. But only about a third of parents said their children came in contact with smoke.
According to Reuters, compared to the information parents gave to doctors, a better predictor of whether they would need to come back to the hospital was finding evidence of nicotine, a chemical in tobacco, in children's saliva.
"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 airway problems and poor asthma control can be caused among children when exposed to tobacco, Kahn and his colleagues write in the journal Pediatrics.
Kahn, a pediatrician at Cincinnati Children's Hospital Medical Center in Ohio, said doctors may be able to step in, identify and possibly eliminate the exposure by figuring out which children are being exposed to tobacco.
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, Reuters reported.
Data from 619 children, aged between one and 16 years old, admitted to Cincinnati Children's Hospital Medical Center for asthma or other breathing problems between August 2010 and October 2011 was taken and assessed by researchers for the new study.
According to Reuters, "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 the children."
Some tobacco exposure was reported by about 35 percent of parents.
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, Reuters reported.
It doesn't necessarily mean that 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, according to Reuters.
"Sometimes a parent's response to a simple question may not reflect the nuances of life," Dr. James Kreindler said, an attending pulmonologist at The Children's Hospital of Philadelphia in Pennsylvania.
According to Reuters, one in six children in the study had to be readmitted to the hospital within a year.
The likelihood of children returning to the hospital wasn't tied to parents' reports of smoke exposure. But Kahn and his colleagues did find that children were more likely to be readmitted if their saliva or blood tested positive for cotinine, Reuters reported.
Since it's not hard or invasive to get a sample, saliva is an attractive testing option, researchers said. 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, Reuters reported.
"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, he noted.
To look at the expense of testing, Kreindler said a cost analysis would also be needed.
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."
