Second-Hand Smoke Worsens Asthma in Kids
From MedPage Today:
More than half of children with asthma are exposed to second-hand tobacco smoke, researchers reported.
The exposure is associated with more doctor visits, disturbed sleep, and restrictions on activity, according to Lara Akinbami, MD, and colleagues at the CDC in Atlanta.
On the other hand, exposure to second-hand smoke is not associated with missing school or wheezing during exercise, Akinbami reported at the annual meeting of the Pediatric Academic Societies in Boston.
National asthma guidelines have advised patients with asthma to avoid tobacco smoke for decades, Akinbami said, but "it's still a problem, and kids are still having impacts," she told MedPage Today.
Overall, Akinbami said, exposure to second-hand tobacco smoke has been falling because of increased awareness of the dangers, but it has not been clear if that's true among the subpopulation of asthmatic children.
To help fill that gap, she and colleagues turned to interview and laboratory data from the National Health and Nutrition Examination Surveys from 2003 through 2010.
The survey consists of health interviews and examinations at a mobile center. Participants are asked about demographic characteristics, smoking in the household, personal smoking habits (if they are 12 or older) and asthma history.
As well, blood samples were taken to assess serum cotinine, which measures exposure to second-hand smoke and personal use of tobacco.
All told, Akinbami reported, they analyzed data for 972 children, ages 6 to 19, who had been diagnosed with asthma by a doctor and reported having current asthma at the time of the survey.
They defined exposure to tobacco smoke as a serum cotinine level of at least 0.05 micrograms per deciliter. Children who reported use of cigarettes, cigars, or pipes were excluded from the analysis.
More than half (53%) of the asthmatic children had exposure to second-hand smoke, Akinbami reported.
In a multivariate analysis, adjusting for differences in age, sex, race, and poverty, exposure to environmental tobacco smoke was associated with a 20% increase in the risk of having one or two visits (compared with none) to a physician's office or emergency department because of wheezing in the past year. The increase was significant at P<0.05.
The trend was similar for more visits and for healthcare use overall, but the confidence intervals on the adjusted risk ratios included unity.
Smoke exposure was associated with a 40% increase in the risk of having limitations on activity, which was also significant at P<0.05. And there was a 40% increase in the risk of having one or more nights a week of disturbed sleep (compared with none) owing to wheezing, significant at P<0.05.
On the other hand, there was no significant increase in the risk of missing school owing to asthma or of wheezing during exercise.
The risk factors for asthma in children, Akinbami said, appear to "align with the risk factors for exposure to second-hand smoke," such as poverty and living in multifamily dwellings.
While advising parents of asthmatic kids to limit exposure to smoke is "a simple message, it's not a simple change to make," she said.
"The bottom line is that these families need more support to really remove this risk from children with asthma," she said.
"The findings are not surprising," commented Jonathan Winickoff, MD, of Massachusetts General Hospital in Boston. "There's a long history of noticing an association between tobacco smoke exposure and both incidence and severity of childhood asthma."
But, Winickoff told MedPage Today, parents "may not know how to protect their child from tobacco smoke exposure."
Many smoking parents, he said, might not be aware of the persistence of their tobacco smoke, whose fine particles cling to surfaces long after a cigarette has been extinguished.
This "third-hand smoke" can elevate cotinine levels in children, said Winickoff, who speaks for the American Academy of Pediatrics on tobacco issues.
Strategies such as not smoking when the kids are around or smoking in the basement don't work, he said, adding there is "really only one safe action that parents can take -- quit smoking."
And even if parents don't smoke themselves, children may still be exposed to second-hand or third-hand smoke because the family lives in multi-unit buildings where other people smoke.