NEW YORK (Reuters Health) – A fall in air pollution levels rapidly reduces airway inflammation in children with asthma and improves airway function, according to study findings reported in the March issue of Pediatrics.

After the 37 children in the study moved from an urban to a rural environment, nasal eosinophil levels dropped fourfold and a significant reduction in fractional exhaled nitric oxide was seen.

“This study provides the first objective evidence that limiting real-life exposure of allergic asthmatic children to outdoor air pollution is followed by measurable reduction in airway inflammation and improved airway function, implying that better air quality may rapidly lead to clinical improvement,” Dr. Giovanni Piedimonte of the West Virginia University, in Morgantown, researchers state.

All of the subjects studied had mild persistent asthma and lived in a highly polluted city before moving to a less polluted rural environment. At both locales, air pollution, pollen counts, and meteorological conditions were monitored.

Relocation to a less polluted environment was also associated with an improvement in lower airway function, as indicated by a marked increase in peak expiratory flow.

Despite the drop in nasal eosinophil levels, no change in urinary leukotriene E4 levels, a product of metabolically active eosinophils, was noted at 1 week after relocation to the rural setting.

The findings suggest that “lowering the exposure of allergic asthmatic children to airborne pollutants is rapidly followed by measurable improvements in airway inflammation and function,” the authors conclude.

Reference:
Pediatrics 2009;123:1051-1058.