Study objective: To examine whether atopy influences
exhaled nitric oxide (NO) levels in adults with established
Setting: Specialist respiratory unit in a
university teaching hospital.
asthmatics (mean FEV1, 85.7%) receiving short-acting
inhaled bronchodilators and a range of inhaled steroids (0 to 4,000μ
Interventions: Subjects were studied on two
occasions, 5 to 7 days apart, between September and March.
Measurements and results: On the first day,
FEV1, exhaled NO, and histamine challenge were performed.
On the second day, exhaled NO, total IgE, and skin-prick testing to six
common allergens were conducted. Exhaled NO was measured with the
single exhalation method. We found exhaled NO levels to correlate
positively with total IgE (r = 0.43, p = 0.02) and
number of positive skin-prick tests (p = 0.002). By contrast, there
was no significant correlation between exhaled NO and FEV1
or the provocative concentration causing a 20% fall in
FEV1. Subanalyses of steroid-treated and steroid-naive
patients in this group revealed the same findings.
Conclusion: Exhaled NO levels in asthmatics correlate more
closely with atopy than with bronchial hyperreactivity and lung