This shows the trends in age-specific asthma mortality rates for England & Wales. The 1960s peak is clear in the 15-44 and 45-64 age-groups. Since the early 1980s, rates among those aged under 64 have tended to decrease, whilst rates in the elderly have increased.

It is not clear to what extent the increase in the elderly is real or due to the effects of changes in coding and diagnostic transfer (LAIA factsheet 92/1). In the last twenty years, there have been three changes in the coding of causes of death. In 1979, a coding rule was abolished which led to an overall increase of 28% in the number of deaths attributed to asthma. In 1983, the re-interpretation of a coding rule (Rule 3) led to a 15% increase in deaths attributed to asthma in the 75+ age-group. In 1992, Rule 3 reverted to its pre-1984 interpretation, although this did not lead to a particularly noticeable decrease in mortality rates. Asthma mortality rates in the elderly are also affected by diagnostic transfer, when deaths which may have been attributed to related diseases such as chronic bronchitis are now labelled as asthma. Despite these coding changes, it is likely that there has been a small real increase in deaths over and above the increases due to coding changes.