Occupational Asthma Reference

Molfino NA, Wright SC, Katz I, Tarlo S, Silverman F, McClean PA, Slutsky AS, Zamel N, Szalai JP, Raizenne M, Effect of low concentrations of ozone on inhaled allergen responses in asthmatic subjects, Lancet, 1991;338:199-203,https://doi.org/10.1016/0140-6736(91)90346-Q

Keywords: ozone, challenge, SIC,

Known Authors

Susan Tarlo, Toronto Susan Tarlo

If you would like to become a known author and have your picture displayed along with your papers then please get in touch from the contact page. Known authors can choose to receive emails when their papers receive comments.

Abstract

The relation between inhalation of ambient concentrations of ozone and airway reactivity to inhaled allergens may be important in asthma, since both agents can produce inflammatory changes in the airways. Seven asthmatic patients (mean age 40 [SD 13] years), with seasonal symptoms of asthma and positive skin tests for ragweed or grass, took part in a study to investigate whether exposure to low concentrations of ozone potentiates the airway allergic response. The patients were studied during 4 separate weeks in the winter. In each week there were 3 study days: on days 1 and 3 methacholine challenges were carried out; and on day 2 the subject received one of four combined challenges in a single-blind design—air breathing followed by inhalation of allergen diluent (placebo); ozone followed by inhalation of allergen diluent; air followed by allergen; or ozone followed by allergen. The ozone concentration was 0·12 ppm during 1 h of tidal breathing at rest, and allergens were inhaled until the forced expiratory volume in 1 s (FEV1) had fallen by 15% (PC15). There were no significant differences in baseline FEV1 after exposure to ozone but PC15 was significantly reduced when allergen was preceded by ozone inhalation: the mean PC15 after air was 0·013 (SD 0·017) mg/ml compared with 0·0056 (0·0062) mg/ml after ozone (p = 0·042). Thus, low ozone concentrations, similar to those commonly occurring in urban areas, can increase the bronchial responsiveness to allergen in atopic asthmatic subjects. This effect does not seem to be the result of changes in baseline airway function.

Plain text: The relation between inhalation of ambient concentrations of ozone and airway reactivity to inhaled allergens may be important in asthma, since both agents can produce inflammatory changes in the airways. Seven asthmatic patients (mean age 40 [SD 13] years), with seasonal symptoms of asthma and positive skin tests for ragweed or grass, took part in a study to investigate whether exposure to low concentrations of ozone potentiates the airway allergic response. The patients were studied during 4 separate weeks in the winter. In each week there were 3 study days: on days 1 and 3 methacholine challenges were carried out; and on day 2 the subject received one of four combined challenges in a single-blind design-air breathing followed by inhalation of allergen diluent (placebo); ozone followed by inhalation of allergen diluent; air followed by allergen; or ozone followed by allergen. The ozone concentration was 0.12 ppm during 1 h of tidal breathing at rest, and allergens were inhaled until the forced expiratory volume in 1 s (FEV1) had fallen by 15% (PC15). There were no significant differences in baseline FEV1 after exposure to ozone but PC15 was significantly reduced when allergen was preceded by ozone inhalation: the mean PC15 after air was 0.013 (SD 0.017) mg/ml compared with 0.0056 (0.0062) mg/ml after ozone (p = 0.042). Thus, low ozone concentrations, similar to those commonly occurring in urban areas, can increase the bronchial responsiveness to allergen in atopic asthmatic subjects. This effect does not seem to be the result of changes in baseline airway function.

Full Text

Full text of this reference not available

Please Log In or Register to add the full text to this reference

Associated Questions

There are no associations for this paper.

Please Log In or Register to put forward this reference as evidence to a question.

Comments

Please sign in or register to add your thoughts.


Oasys and occupational asthma smoke logo