Impact of environmental tobacco smoke on children with asthma, United States, 2003-2010

Objective: Given widespread interventions to reduce environmental tobacco smoke (ETS) exposure and improve asthma control, we sought to assess the current impact of ETS exposure on children with asthma.

Methods: We analyzed 2003-2010 data for nonsmoking children aged 6 to 19 years with asthma from the National Health and Nutrition Examination Survey. Outcomes (sleep disturbance, missed school days, health care visits, activity limitation, and wheezing with exercise) were compared between ETS exposed children (serum cotinine levels 0.05 to 10 ng/mL) and unexposed children (<0.05 ng/mL) using ordinal regression adjusted for demographic characteristics. We also assessed whether associations were observable with low ETS exposure levels (0.05 to 1.0 ng/mL).

Results: Overall, 53.3% of children aged 6 to 19 years with asthma were ETS exposed. Age-stratified models showed associations between ETS exposure and most adverse outcomes among 6- to 11-year-olds, but not 12- to 19-year-olds. Even ETS exposure associated with low serum cotinine levels was associated with adverse outcomes for 6- to 11-year-olds. Race-stratified models for children aged 6 to 19 years showed an association between ETS exposure and missing school, health care visits, and activity limitation due to wheezing among non-Hispanic white children, and disturbed sleep among non-Hispanic white and Mexican children. Among non-Hispanic black children, there was no elevated risk between ETS exposure and the assessed outcomes: non-Hispanic black children had high rates of adverse outcomes regardless of ETS exposure.

Conclusions: Among children with asthma 6 to 11 years of age, ETS exposure was associated with most adverse outcomes. Even ETS exposure resulting in low serum cotinine levels was associated with risks for young children with asthma.