Expired nitric oxide levels in adult asthmatics

The expired nitric oxide (NO) concentration is known to be higher in asthmatic subjects than in normal subjects. To elucidate the role of NO in asthma, we examined the expired NO concentrations in relation to the type (atopic, mixed, non- atopic), and severity (mild, moderate, severe) of asthmatics, as well as the influence of steroid treatment. Twenty-seven normal subjects, 48 asthmatics, 8 subjects with allergic rhinitis, and 13 subjects with pulmonary emphysema participated in the study. The expired NO concentration was significantly higher in asthmatics and patients with allergic rhinitis than in normal subjects (P<0.01). No significant difference was observed between the expired NO concentration in patients with pulmonary emphysema and that of normal subjects. The expired NO concentrations were significantly lower in non- atopic asthma than in atopic asthma. Nitric oxide levels were significantly lower in severe asthma than in mild asthma. High doses of steroid treatment are often used in severe asthma. The dose of inhaled beclomethasone and expired NO concentrations showed a negative correlation (r= −0.51587, P