Labelling shift from acute bronchitis may be contributing to the recent rise in asthma mortality in the 5-34 age group.

To test the hypothesis that labelling shift from acute bronchitis to asthma may be contributing to the rise in deaths from asthma in the U.K., we studied mortality rates for males, females and both sexes combined for all ages and for the 5-34 age group, from published mortality tables from 1950 to 1985. The 5-34 age group mortality from asthma showed the 1960s peak and a more gradual increase from 1975. Mortality (all ages) from acute bronchitis showed a decline over the period, but in the 5-34 age group mortality was remarkably stable from 1950-1974 with a mean rate of 2.61 per million (95% confidence intervals, 2.44-2.78). From 1975 to 1985 the rate declined linearly to 0.75 per million. The number of acute bronchitis deaths 'saved' over this period was 366 compared to the number of excess asthma deaths during the same period (taking the 1974 rate as baseline) of 514. These findings lend support to the hypothesis that, in the 5-34 age group, labelling shift from acute bronchitis to asthma may be a contributing factor to the recent rise in asthma mortality. They also raise the question whether different factors contributing to the rise in asthma may have proportionately different weights of effect according to the age of the patients involved.