Clinical trial NCT00006565: Randomized Trial to Reduce Environmental Tobacco Smoke in Children With Asthma
Official title: Randomized Trial to Reduce Environmental Tobacco Smoke in Children With Asthma
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE3
Conditions: Asthma
Lung Diseases
Keywords: asthma
HEPA
ETS
Lead sponsor: National Heart, Lung, and Blood Institute (NHLBI)
Sponsor class: NIH
First posted: 2000-12-01
Enrollment: 225
Sex: ALL
Minimum age (years): 6
Maximum age (years): 12
Standard ages: CHILD
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: The purpose of this study is to test the effects of reducing indoor environmental tobacco smoke (ETS) on unscheduled asthma visits, asthma symptoms, airway inflammation, and exposure to tobacco smoke measured using air nicotine dosimeters, serum and hair cotinine.

Detailed description: 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.

Eligibility criteria: Inclusion Criteria:

* Age 6-12 years at enrollment
* Doctor diagnosed asthma by ICD-9 billing codes (from billing records)
* Greater than 1 exacerbation(s) in the past year requiring an unscheduled asthma visit
* Exposed to the smoke of greater than or equal to 5 cigarettes in and around the house per day
* Lived within a 9-county area surrounding the city of Cincinnati

Exclusion Criteria:

* Already using a HEPA air cleaner
* Lacked electricity
* Had a coexisting medical problem
* Family planned to move in the next year

Primary outcomes:
measure: Unscheduled asthma visits
timeFrame: Measured at 12 months
Secondary outcomes:
measure: Asthma symptoms
timeFrame: Measured at 12 months
measure: Exhaled nitric oxide
timeFrame: Measured at 12 months
measure: Tobacco smoke exposure, measured using air nicotine dosimeters, serum cotinine and hair cotinine
timeFrame: Measured at 12 months
Other outcomes:
Locations:
Study officials:
affiliation: Simon Fraser University
name: Bruce P Lanphear, MD, MPH
role: PRINCIPAL_INVESTIGATOR
References:
citation: Wilson SE, Kahn RS, Khoury J, Lanphear BP. Racial differences in exposure to environmental tobacco smoke among children. Environ Health Perspect. 2005 Mar;113(3):362-7. doi: 10.1289/ehp.7379.
citation: Spanier AJ, Hornung RW, Kahn RS, Lierl MB, Lanphear BP. Seasonal variation and environmental predictors of exhaled nitric oxide in children with asthma. Pediatr Pulmonol. 2008 Jun;43(6):576-83. doi: 10.1002/ppul.20816.
citation: Spanier AJ, Hornung R, Lierl M, Lanphear BP. Environmental exposures and exhaled nitric oxide in children with asthma. J Pediatr. 2006 Aug;149(2):220-6. doi: 10.1016/j.jpeds.2006.04.001.
citation: Wilson SE, Kahn RS, Khoury J, Lanphear BP. The role of air nicotine in explaining racial differences in cotinine among tobacco-exposed children. Chest. 2007 Mar;131(3):856-862. doi: 10.1378/chest.06-2123.
citation: Lanphear BP, Hornung RW, Khoury J, Yolton K, Lierl M, Kalkbrenner A. Effects of HEPA air cleaners on unscheduled asthma visits and asthma symptoms for children exposed to secondhand tobacco smoke. Pediatrics. 2011 Jan;127(1):93-101. doi: 10.1542/peds.2009-2312. Epub 2010 Dec 13.