AIRWEIGHS: A Randomized Controlled Trial of Air Cleaners in Normal Weight and Overweight/Obese Children With Asthma.

BACKGROUND

Overweight and obesity are risk factors for increased asthma morbidity among children, and overweight/obese children with asthma may be more susceptible to air pollution.

OBJECTIVE

To test the hypothesis that there would be greater improvement in asthma from an air cleaner intervention to reduce indoor air pollution among overweight/obese children compared with normal weight children.

METHODS

AIRWEIGHS is a randomized, placebo-controlled air cleaner trial designed to reduce indoor air pollution and test the differential health impact among overweight/obese children versus normal weight children with asthma. Asthma outcomes and home air pollution were measured at baseline and 12 weeks after intervention. The primary outcome was maximum symptom days over 2 weeks, defined as the largest value of days of slowed activity, number of nights of waking, and days of coughing, wheezing, and chest tightness due to asthma. Secondary outcomes included asthma questionnaires, lung function, fractional exhaled nitric oxide, and exacerbations.

RESULTS

A total of 164 children (aged 10.9 ± 2.5 years, 41% female, 85% Black, and 59% overweight/obese) were randomized to portable air cleaners with high-efficiency particulate air filters or identical devices without filters. Average baseline air pollutants (ultrafine particle [UFP]: 45.3 μm2/m3, particulate matter, aerodynamic diameter ≤2.5 μm [PM2.5]: 24.0 μg/m3, PM, aerodynamic diameter ≤10 μm [PM10]: 33.0 μg/m3, nitric dioxide [NO2]: 16.7 ppb) did not differ by study group. There were greater reductions in the intervention group versus the placebo group (UFP: 64.0%, PM2.5: 64.4%, PM10: 54.7%, NO2: 11.7%; P < .05 each). There was no improvement in primary or secondary outcomes, with no difference between normal weight and overweight/obese children.

CONCLUSION

Air cleaners effectively reduced indoor air pollution, but there was no observable benefit in asthma outcomes in children.