SELECTED ARTICLES FROM THE RECENT LITERATURE 2003
9/24/03
Personal exposure to nitrogen dioxide, and the severity of virus infection -
triggered asthma in children
Summary
Virus infections are usually the most common triggers of acute asthma
exacerbations. A link between exposure to ambient nitrogen dioxide (NO2) and
asthma worsening has been suggested. Chauhan et al of the Univ. of
Southhampton in the UK studied 114 childhood asthmatics (ages 8-11 years)
with daily measurements as well as ambient levels of NO2 for up to 13
months. One or more viruses were found in 78% of patient/parent reported
respiratory infections. Exposure to higher concentrations of NO2 during the
week before onset of the viral respiratory infection were associated with
more severe lower respiratory tract symptoms and decreases in peak flow
rates during such infections.
Reference
Lancet 2003; 36:1939-44
Editor’s Comments
NO2, which is emitted mostly by gas cooking appliances and motor vehicles,
has been long suspected to be a respiratory irritant. What is striking (and
perhaps disturbing) in this current study is that the "high" NO2 levels
associated with more severe asthmatic reactions during subsequent viral
infections were actually within "acceptable" levels by international
guidelines. One would expect even higher NO2 levels in geographic areas such
as the Los Angeles vicinity with its heavy auto traffic and propensity to
smog formation. A recent study from that city suggested that NO2 may cause
symptoms of chronic bronchitis in asthmatic children (Am J Respir Crit Care
Med, July 2003). Other studies have not found a clear-cut association
between NO2 levels and the frequency of acute asthma flares seen in
Emergency Depts.
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