Physical Activity and Bronchial Hyperresponsiveness: European Community Respiratory Health Survey II

Abstract

Identification of the risk factors for bronchial hyperresponsiveness would increase understanding of the causes of asthma. We investigated the relationship between physical activity and bronchial hyperresponsiveness in men and women, from 28.0 to 56.5 years of age, randomly selected from 24 centers in 11 countries participating in the European Community Respiratory Health Survey II. 5,158 subjects answered questionnaires about physical activity and performed bronchial hyperresponsiveness tests. Participants were asked frequency and duration of usual weekly exercise resulting in breathlessness or sweating. Bronchial hyperresponsiveness was defined as a decrease in forced expiratory volume in 1 second of at least 20% of its post-saline value for a maximum methacholine dose of 2 mg. Both frequency and duration of physical activity were inversely related to bronchial hyperresponsiveness. The prevalence of bronchial hyperresponsiveness in subjects exercising once or less a week, 2-3 times a week and four or more times a week was 14.5%, 11.6% and 10.9%, respectively (p<0.001). The corresponding Odd-ratios [95% CI] were 1.00, 0.78 [0.62-0.99] and 0.69 [0.50- 0.94] after controlling for potential confounding factors. Bronchial hyperresponsiveness frequency in subjects exercising less than1 hour a week, 1-3 hours and four or more hours a week was 15.9%, 10.9% and 10.7%, respectively (p<0.001). The corresponding adjusted Odd-ratios [95% CI] were 1.00, 0.70 [0.57-0.87] and 0.67 [0.50-0.90]. Physical activity was associated with bronchial hyperresponsiveness in all studied subgroups. These results suggest that bronchial hyperresponsiveness is strongly and independently associated with decreased physical activity. Further studies are needed to determine the mechanisms underlying this association.