Progress in Chronic Disease Prevention
Chronic Disease Reports: Mortality Trends -- United States,
1979-1986
CDC's National Center for Health Statistics (NCHS) has developed
the
system by which deaths are reported, coded, and tabulated to
produce
official U.S. mortality statistics (1). Crude and adjusted
mortality
rates as reported by NCHS are the standard for reporting mortality
statistics. Some alternative approaches may be useful to focus on
particular events of epidemiologic importance (2). This report
describes U.S. mortality trends from 1979 to 1986 using two
departures
from standard mortality reporting: the data were age-adjusted to
the
1980 total U.S. population, and in some cases, different
International
Classification of Diseases, Ninth Revision, Clinical Modification
(ICD-9-CM) groupings were used to form diagnostic categories (e.g.,
chronic obstructive pulmonary disease (OPD) included only cases
likely
to be associated with smoking).
Between 1979 and 1986, the total age-standardized mortality rate
in
the United States declined by 8%. However, this "average" change
obscures considerable diversity in changing mortality rates for
specific diseases: nine major chronic disease groupings
demonstrated
differing trends over this period (Figure 1). The largest decreases
occurred for stroke (ICD-9-CM 430-434, 436-438)*, coronary heart
disease (CHD) (ICD-9-CM 410-414, 429.2), and cirrhosis (ICD-9-CM
571)
(Figure 1). In contrast, the portion of OPD likely to be related to
smoking (ICD-9-CM 491, 492, 496) increased by 33% and lung cancer
(ICD-9-CM 162), by 15%. Three cancers showed diverse trends: female
breast cancer (ICD-9-CM 174) increased by 5%; colorectal cancer
(ICD-9-CM 153, 154) declined by 7%, and cervical cancer (ICD-9-CM
180)
declined by 18%. Diabetes mellitus (ICD-9-CM 250) decreased
moderately
(3%) as an underlying cause of death.
Reported by: Office of the Director, Center for Chronic Disease
Prevention and Health Promotion; Epidemiology and Surveillance Br,
Div
of Surveillance and Epidemiologic Studies, Epidemiology Program
Office,
CDC.
Editorial Note
Editorial Note: The diverse trends in mortality for these nine
diseases suggest that shared risk factors may have different
effects.
For example, the overall national prevalence of smoking declined by
13%
(from 33.5% to 29.1%) during 1979-1987 (3). During the same period,
stoke and CHD mortality decreased substantially; in contrast,
smoking-related OPD and lung cancer mortality markedly increased.
This
diversity in the trends for smoking-related disorders may result
from a
combination of epidemiologic circumstances. Smoking is a stronger
risk
factor (i.e., is associated with greater relative risks) for lung
cancer and this grouping of OPD than for stroke or heart disease
(4).
In addition, the latency between initiation of smoking and
subsequent
death is much longer for persons with pulmonary sequelae; recent
mortality trends are thus less likely to be associated with recent
trends in the risk factor. Finally, smoking may be the primary
causative agent in lung cancer and this grouping of OPD, whereas
smoking is only one of several interrelated risks for stroke and
heart
disease. Prevalences of these risks, which include hypertension,
hypercholesterolemia, physical inactivity, and obesity, may have
changed among the population in recent years (5).
The divergent trends in breast and cervical cancer mortality may
also
result from a variety of risk factors (4,6), of which few are
amenable
to direct intervention. Effective screening tests are available for
both cancers. The Pap smear for cervical cancer is a
well-established
clinical tool, and its use may account for some of the decline in
cervical cancer mortality. However, efficacy of the Pap smear has
never
been directly tested nor a systematic national program for its
application conducted. The screening mammogram, a more recent
development, was effective in a controlled setting (7), but no
systematic national program exists for the widespread dissemination
of
mammographic services. The lack of such a program may not directly
contribute to the increase in mortality but could be important in
the
failure to demonstrate desired decreases. Finally, the age, race,
and
socioeconomic differences in survival patterns exhibited by persons
with cervical or breast cancer, as well as by those
with colorectal cancer (8), may also play an important role in
current
mortality trends.
Death attributed to a chronic disease results from a series of
intertwined biologic and epidemiologic events, including
interactions
among risk factors, diseases, and coding practices. Although
cause-specific mortality trends using nonstandard rubrics are a
useful
measure of overall effect, they must be interpreted cautiously.
Nonstandard use of diagnostic categories provides opportunities for
special epidemiologic focus, but care should be taken to make such
use
explicit.
References
CDC. Mortality data from the National Vital Statistics System.
MMWR
1989;38:118-23.
2.CDC. Chronic disease reports in the Morbidity and Mortality
Weekly
Report (MMWR). MMWR 1989;38(suppl S-1).
3.CDC. Reducing the health consequences of smoking: 25 years of
progress--a report of the Surgeon General, 1989. Rockville,
Maryland:
US Department of Health and Human Services, Public Health Service,
1989; DHHS publication no. (CDC)89-8411.
4.Rothenberg R, Nasca P, Mikl J, Burnett W, Reynolds B. Cancer. In:
Amler RW, Dull HB, eds. Closing the gap: the burden of unnecessary
illness. New York: Oxford University Press, 1987:30-42.
5.CDC. Behavioral Risk Factor Survey data, 1981-1987. Atlanta: US
Department of Health and Human Services, Public Health Service,
1988.
6.Thomas DB. Epidemiologic and related studies of breast cancer
etiology. In: Lilienfeld AM, ed. Reviews in cancer epidemiology.
Vol 1.
New York: Elsevier/North-Holland, 1980:153-217.
7.Shapiro S, Venet W, Strax P, Venet L, Roeser R. Ten- to
fourteen-year effect of screening on breast cancer mortality. JNCI
1982;69:349-55.
8.National Cancer Institute. Annual cancer statistics review, 1987.
Bethesda, Maryland: US Department of Health and Human Services,
Public
Health Service, National Institutes of Health, 1988; NIH
publication
no. 88-2789.
*See Chronic Disease Reports: Stroke figure and tables following
this
article.
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