Death rates for specific causes decreased significantly as the United States left
the early stages of the epidemiologic transition and moved into the last stage.
Table 5-1, which gives age-adjusted death rates for various causes in the entire
population, and Tables 5-2 and 5-3 which do so for whites and blacks, respec-
tively, show the progress between 1940 and 1988 in virtually eliminating some
causes and greatly reducing the virulence of most others, though notably not all.

There are some methodological concerns in comparing the two years because
five revisions of the International Classification of Diseases altered the categories
of causes. For example, some subcategories of cardiovascular diseases were
created and others redefined substantially after 1940. The Ninth Revision of the
ICD, prepared in 1975 and first applied to 1979 data, is used extensively in this
book, although the NCHS also modified parts of that revision for U.S. purposes.
In addition, while the standard population for computing age-adjusted death rates
was enumerated in 1940 and it is best to trace as many trends as possible from
that year, some sections also follow detailed trends from later years, often 1950
or even 1979, particularly for subcategories of cancer. In a few cases trends are
even shorter. The first cases of HIV infections, for example, were not reported
officially until 1981 and a separate category was not created for HIV until 1987.

Despite changes in categories of causes and in the time span used to identify
trends, the causes listed in Tables 5-1 through 5-3 are reasonably comparable
for 1940 and 1988. The data show many significant reductions and some major
increases during nearly a half century of progress in medicine, sanitation, nu-
trition, and health awareness and maintenance. ¹ The changes parallel trends in
most other developed countries, where cardiovascular diseases now head the list
of causes, followed by cancer and external causes, especially motor vehicle
accidents and suicide. ²

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