Trends in Australian mortality of asthma, 1979-1985.

Trends in Australian mortality rates that have been ascribed to asthma and to non-tuberculous, non-malignant respiratory diseases were examined for the period 1979-1985. Mortality rates of asthma and respiratory diseases increased substantially from 1979 to 1985, and in the case of asthma, the crude death rate in 1985 was higher than at the peak of the "epidemic" of the 1960s. The increase in mortality of asthma was most pronounced in those of greater than 60 years of age (from 11.5 per 100,000 such population in 1979 to 22.9 per 100,000 such population in 1985). Asthma mortality rates in five- to 34-year-old persons increased, although there were marked yearly fluctuations, and deaths of asthma in this age-group comprised only a small percentage (13% in 1985) of all deaths of asthma. Reasons that are considered for the rising death rate of asthma include changes in diagnostic fashion; an increase in the incidence or a change in the natural history of asthma; and an increased case fatality rate. With the presently-available data, it is not possible to distinguish among these possible explanations.