Rabinovitch N, Strand M, Gelfand EW. Am J Respir Crit Care Med. 2006;173:1098–1105
PURPOSE OF THE STUDY. To determine if exposure to particulate matter has immediate effects on asthma control in children with persistent disease.
STUDY POPULATION. Seventy-three schoolchildren (aged 6–13 years) with physician-diagnosed asthma in Denver, Colorado, were studied.
METHODS. Over 2 consecutive winters, the subjects were followed daily. The association among ambient fine-particulate levels, bronchodilator use, and urinary leukotriene E4 levels was assessed.
RESULTS. Fine-particulate concentrations peaked in the morning hours during hours when children were commuting to school. Children with severe asthma had a stronger association (+8.1%) than those with mild-to-moderate disease (+1.6%), with increased bronchodilator usage at school on days with an increase of 1 interquartile range in morning maximum fine-particulate levels. Morning maximum fine-particulate levels were also associated with urinary leukotriene E4 measured during school hours (average increase of 6.2% per interquartile-range increase).
CONCLUSIONS. Peak concentrations of ambient fine particulate are associated with early increases in bronchodilator use and urinary leukotriene E4 levels among children with persistent asthma, despite the use of controller medications.
REVIEWER COMMENTS. Managing patients with asthma requires knowing possible triggers. This study examined the timing of particulate associations with disease control in children with moderate or severe asthma who were taking controller medications. The interval between exposure and initiation of health effects was seen to occur within the first few minutes or hours after exposure. The effects were strongest in children with more severe asthma. This effect plus the increase in urinary leukotriene E4 levels suggest that in children with persistent asthma, particulate exposure may lead to early release of mediators related to asthma worsening. This study suggests that in children with poorly controlled asthma, air-pollution effects (well below National Ambient Air Quality standards) may be observed despite the use of daily controller medications.
- Copyright © 2007 by the American Academy of Pediatrics