Household Smoking and Childhood Asthma in the United States: A State-Level Analysis.

Background. The reason for the substantial geographic variation in the prevalence of childhood asthma is not known. Objective. To investigate the association between exposure to cigarette smoking in the home and childhood asthma at the state-level, toward improving current understanding of geographic variation in childhood asthma rates. Methods. Data were drawn from the National Children's Health Survey (NCHS, 2003), a representative sample (n = 102, 000) of youth 0 to 17 years of age in the United States. Household smoking and asthma in children were reported by parents. Air quality for each state was obtained from Environmental Protection Act (EPA) reports, and state-level poverty reports were obtained from the US Department of Agriculture. Results. Household smoking was associated with a statistically significant increase in risk of asthma among children at the state level (p = 0.026). This association did not appear to be influenced by outdoor air quality at the state level or socioeconomic position. Conclusions. These results are the first to show a link between cigarette smoking in the home and childhood asthma at a state-level in the United States. [ABSTRACT FROM AUTHOR]