Airway Hyperresponsiveness and Quality of Life in Western Red Cedar Asthmatics Removed from Exposure

Objectives

Most western red cedar asthmatics (WRCA) continue to have symptoms even after removal from exposure. Consequently, health-related quality of life (HRQL) is often impaired. The objective of this study was to evaluate the relationship between two measures of AHR and HRQL scores in those with WRCA.

Methods

HRQL was determined by the short form 36 (SF-36) in 46 male, non-smoking individuals with WRCA removed from exposure to western red cedar, on average, 15 years earlier. The relationships between the SF-36 total score and its eight domains with 2 indices from methacholine-stimulated airway hyperresponsiveness (the provocative concentration of methacholine causing a 20% fall in FEV₁ PC₂₀] and bronchial reactivity index BRI]) were analyzed by the Pearson correlation and multiple linear regression.

Results

PC₂₀ was significantly correlated with the SF-36 total score and its two domains of bodily pain and general health (r = 0.34, 0.40, 0.40, p = 0.023, 0.006, 0.006, respectively). BRI was significantly correlated with bodily pain and general health (r = −0.35, −0.42, p = 0.017, 0.004, respectively); correlations remain significant after adjusting for age, ethnicity, years since diagnosis, years since last exposure and use of inhaled corticosteroid. BRI and other measures of airway responsiveness were not associated with inhaled corticosteroids use.

Conclusions

In Western red cedar asthmatics removed from exposure, measures of airway responsiveness are associated with HRQL.