Ken Quinto at the National Center for Health Statistics, part of the Centers for Disease Control and Prevention, analyzed national survey data and found a difference between children exposed and not exposed to secondhand smoke.
The study found children with asthma are more likely than kids without asthma to have to breathe secondhand smoke, Quinto said.
"From 1999-2010, the percentage of children without asthma exposed to secondhand smoke decreased from 57 percent to 44 percent," Quinto said in a statement.
Nearly 58 percent of children with asthma were exposed to environmental tobacco smoke from 1999-2002 and 54 percent exposed from 2007-10, which isn't a significant difference, Quinto said.
Children with asthma exposed to secondhand smoke have more severe asthma symptoms and more frequent outbreaks than other children with asthma not exposed to smoked, Quinto said.
"The message isn't getting through to parents who smoke," Quinto added.
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