Abstract |
The relationship of airways responsiveness to respiratory symptom prevalence has been studied in a cross sectional analysis of a random subpopulation from a large scale population study on chronic obstructive lung disease (COLD) being conducted in the Netherlands. In 1905 subjects with complete data on age, sex, area of residence, smoking habits, and respiratory symptom prevalence, airways responsiveness was assessed by a histamine challenge test. Subjects with a decrease in FEV1 of at least 10% at histamine concentrations up to 16 mg ml were considered to be responders. Bronchial hyperresponsiveness appeared to be age dependent with the proportion of responders increasing from 13% in the age group 14-24 to 40% in the age group of 55-64. Respiratory symptom outcomes included chronic cough, chronic phlegm, dyspnea, bronchitis episodes, persistent wheeze and asthmatic attacks. Respiratory symptom prevalence rates were significantly higher in responders. Regardless of smoking category, responders were more likely to be symptomatic than nonresponders. Both cigarette smoking and bronchial responsiveness were significantly associated with each symptom in a dose-response relationship. The results are consistent with the hypothesis that nonspecific bronchial responsiveness is associated with the occurrence of chronic respiratory symptoms. |