Smoke-free air laws and asthma prevalence, symptoms, and severity among nonsmoking youth.

OBJECTIVE We investigated the association between smoke-free laws and asthma prevalence, symptoms, and severity among nonsmoking youth (aged 3-15 years). METHODS We examined data from the 1999-2006 National Health and Nutrition Examination Survey, a cross-sectional survey designed to monitor the health and nutritional status of the US population. Survey… (More)