Mortality in adults with self-reported asthma. Copenhagen City Heart Study Group.

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.