Environmental tobacco smoke exposure in children aged 3-19 years with and without asthma in the United States, 1999-2010.

KEY FINDINGS Data from the National Health and Nutrition Examination Survey, 1999-2010. From 1999 to 2010, the percentage of children without asthma exposed to environmental tobacco smoke (ETS) decreased from 57.3% to 44.2%, while children with asthma showed no change, with 57.9% exposed to ETS in 1999-2002 and 54.0% exposed in 2007-2010. In 2007-2010, a higher percentage of children with asthma were exposed to ETS than children without asthma. In 2007-2010, children with asthma were more likely to be exposed to ETS than children without asthma, if they were girls, Mexican American, aged 6-11 years, or had family income below 350% of the federal poverty guidelines.