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| EFFECT OF LOW CONCENTRATIONS OF OZONE ON INHALED ALLERGEN RESPONSES IN ASTHMATIC SUBJECTS |
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| Author(s): MOLFINO NA, WRIGHT SC, KATZ I, TARLO S, SILVERMAN F, MCCLEAN PA, SZALAI JP, RAIZENNE M, SLUTSKY AS, ZAMEL N |
| Source: LANCET Volume: 338 Issue: 8761 Pages: 199-203 Published: JUL 27 1991 |
| Times Cited: 276 References: 30 |
| 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 FEV, 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. |
| Document Type: Article |
| Language: English |
Addresses:
1. UNIV TORONTO, DEPT MED, TORONTO M5S 1A1, ONTARIO CANADA
2. UNIV TORONTO, DEPT PREVENT MED & BIOSTAT, TORONTO M5S 1A1, ONTARIO CANADA
3. HLTH & WELF CANADA, OTTAWA K1A 0L2, ONTARIO CANADA |
| Publisher: LANCET LTD, 42 BEDFORD SQUARE, LONDON, ENGLAND WC1B 3SL |
| Subject Category: Medicine, General & Internal |
| IDS Number: FY504 |
| ISSN: 0140-6736 |
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