Randomized Trial to Reduce Environmental Tobacco Smoke in Children With Asthma

BACKGROUND: Asthma, a disease characterized by increased airway reactivity and inflammation in response to a variety of stimuli, is emerging as the most prevalent and serious environmental health problem among children in the United States. Numerous studies, both prospective and cross-sectional, suggest that exposure to ETS is one of the predominate risk factors for childhood asthma, but this has not been confirmed in a controlled trial. DESIGN NARRATIVE: The randomized, double-blind prospective trial involving 225 children with doctor-diagnosed asthma who are exposed to environmental tobacco smoke tests the efficacy of reducing such exposure on unscheduled asthma visits and asthma symptoms. The intervention consists of placement of 2 high efficiency air filtration with activated carbon, potassium permanganate and zeolite filter insert to reduce exposure to ETS in the experimental homes and inactive (placebo) units in the control group homes. The following hypotheses are tested. (1.0) Children assigned to the ETS reduction group will have a greater than 20 percent reduction in unscheduled asthma visits during one-year follow-up compared with those in the control group. (1.1) Children assigned to the ETS reduction group will have significant improvements in asthma symptoms compared with children in the control group. (1.2) Children assigned to the ETS reduction group will have greater than 10 percent reduction in ETS exposure and exhaled nitric oxide, a measure of airway inflammation during one year of follow-up compared with the control group.