P Lange1, C S Ulrik, J Vestbo. 1. Epidemiological Research Unit, Rigshospitalet, Copenhagen, Denmark.
Abstract
BACKGROUND: On the question of whether asthma shortens survival the published work gives no clear answer. We have prospectively analysed overall and cause-specific mortality in persons with self-reported asthma. METHODS A sample of 13 540 individuals (6104 men) 20 years of age or older, randomly selected from the general population of the city of Copenhagen, was followed for 17 years. FINDINGS: Survival in participants with self-reported asthma was significantly poorer than in non-asthmatics, the excess mortality being limited to pulmonary mortality. After statistical adjustment for age, length of school education, and smoking, women with asthma had a 1.7 higher risk of dying than women without asthma (95% confidence interval 1.3--2.2). Although the relative risk (RR) of dying with asthma was slightly lower in men (RR = 1.5, 95% Cl 1.2-1.9) the difference between sexes was not significant. The results were similar within smoking groups and the highest risk of death associated with asthma was seen among never-smokers (RR = 2.1, 95% Cl 1.6-2.3). Inclusion of one-second forced expiratory volume, in % predicted, in the mortality analyses showed that the increased risk of death associated with asthma was mediated mainly through reduced lung function. INTERPRETATION: We conclude that, in the general population, self-reported asthma is associated with a slight excess of mortality, mainly from respiratory diseases.
BACKGROUND: On the question of whether asthma shortens survival the published work gives no clear answer. We have prospectively analysed overall and cause-specific mortality in persons with self-reported asthma. METHODS A sample of 13 540 individuals (6104 men) 20 years of age or older, randomly selected from the general population of the city of Copenhagen, was followed for 17 years. FINDINGS: Survival in participants with self-reported asthma was significantly poorer than in non-asthmatics, the excess mortality being limited to pulmonary mortality. After statistical adjustment for age, length of school education, and smoking, women with asthma had a 1.7 higher risk of dying than women without asthma (95% confidence interval 1.3--2.2). Although the relative risk (RR) of dying with asthma was slightly lower in men (RR = 1.5, 95% Cl 1.2-1.9) the difference between sexes was not significant. The results were similar within smoking groups and the highest risk of death associated with asthma was seen among never-smokers (RR = 2.1, 95% Cl 1.6-2.3). Inclusion of one-second forced expiratory volume, in % predicted, in the mortality analyses showed that the increased risk of death associated with asthma was mediated mainly through reduced lung function. INTERPRETATION: We conclude that, in the general population, self-reported asthma is associated with a slight excess of mortality, mainly from respiratory diseases.