To test the effects of reducing indoor environmental tobacco smoke (ETS) on asthma symptoms, pulmonary function, airway inflammation, and health services utilization.

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 240 children with doctor-diagnosed asthma who are exposed to environmental tobacco smoke tests the efficacy of reducing such exposure on asthma symptoms. The intervention consists of placement of 2 high efficiency air filtration with activated carbon, potassium permanganate and zeolite filter insert (HEPA-CPZ) 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 significant improvements in asthma symptoms and pulmonary function compared with children in the control group. (1.1) Children assigned to the ETS reduction group will have greater than 25 percent reduction in exacerbations of asthma during one year of follow-up compared with those in the control group. (1.2) Children assigned to the ETS reduction group will have improvement in pulmonary function as measured by greater than 10 percent difference in forced expiratory volume at 1 second (FEV 1) and greater than 15 percent difference in forced expiratory fraction of 25 percent-75 percent (FEF25-75 percent) at 12-month follow-up compared with those in the control group. (1.3) Children assigned to the ETS reduction group will have greater than 10 percent reduction in exhaled nitric oxide, a measure of airway inflammation during one year of follow-up compared with the control group. (1.4) Children assigned to the ETS reduction group will have a greater than 20 percent reduction in health services utilization for asthma during one-year follow-up compared with those in the control group. (2.0) Children who are exposed to higher levels of ETS, as measured by cotinine, will experience higher rates of asthma symptoms and diminished pulmonary function in a dose-response relationship.

Genders Eligible for Study:  Both

Criteria