Bronchoconstrictor responses to sulfur dioxide or sulfur dioxide plus sodium chloride droplets in allergic, nonasthmatic adolescents

Abstract

Eight atopic adolescent subjects without diagnosis of clinical asthma but with signs of hyperactive airways were studied. The subjects were exposed for 30 min at rest followed by 10 min during moderate exercise on a treadmill to the following: (1) filtered air, (2) 1 mg/m 3 NaCl droplet aerosol, (3) 1 ppm SO 2 and NaCl droplet aerosol, or (4) 1 ppm SO 2 . All exposures were at 75% relative humidity and 22 °C. Exposures to either SO 2 mode produced statistically significant changes in pulmonary function, whereas sham exposures to air on NaCl did not. These results are similar to those seen earlier in a group of extrinsic asthmatic adolescent subjects and are three to 22 times greater than changes we saw in a group of normal adolescent subjects. The changes seen after inhalation of SO 2 were not statistically different from those seen after inhalation of SO 2 and NaCl droplet aerosol. Our results indicate that inhalation of 1 ppm SO 2 by a group of atopic adolescents can produce exercise-induced bronchospasm at a level of exercise that has no effect by itself.