Abstract

BACKGROUND: Obstructive airways disease adversely affects quality of life, although relationships between quality of life and lung function have been shown to be weak. The relationships between the results of a quality of life questionnaire, spirometric tests, and methacholine bronchial challenge were investigated in a population sample of middle aged and elderly people. METHODS: A random population sample of the white population of Central Manchester, UK were contacted by post. Respondents were invited to undergo bronchial challenge with methacholine (Newcastle dosimeter method) and to complete the St George's Respiratory Questionnaire. This self-completed questionnaire quantifies quality of life as three component scores, with higher scores indicating greater impairment of quality of life. RESULTS: Two hundred and twenty seven subjects aged 45-86 years completed the St George's Questionnaire and performed spirometric tests; 190 completed the methacholine challenge. All quality of life scores were higher in subjects with a forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) of < 65%, indicating impaired quality of life in subjects with airways obstruction. There was no relationship between quality of life and age. Multiple regression analysis showed independent relationships between quality of life scores and both baseline FEV1 and bronchial responsiveness. However, the amount of variation in quality of life attributable to variation in FEV1 or bronchial responsiveness was less than 10%. Subgroup analysis indicated that the quality of life score was independently associated with bronchial responsiveness and not FEV1 in subjects aged < 65 years, but with baseline FEV1 and not bronchial responsiveness in older subjects. CONCLUSIONS: Obstructive airways disease significantly impairs quality of life in adults. The reduction in quality of life in these patients is related to both baseline pulmonary function and non-specific bronchial responsiveness. The impact of airways obstruction on quality of life does not decrease with advancing age.