Competing causes of death. A review of recent trends in mortality in industrialized countries with special reference to cancer

Abstract

In most industralized countries, the last two decades or so have been characterized by a further significant reduction in mortality. Summary measures of mortality, such as the age-standardized death rate, have declined in parallel with reductions in CVD mortality. Yet, cancer mortality over all ages has risen in the majority of industralized countries. However, this rise in cancer mortality has been accompanied by a rise in the average age at death from the disease, suggesting further progress in deferring death. How much of the observed increase in cancer mortality for such sites as the brain, as well as for multiple myeloma, is real is difficult to determine. Certainly, for countries such as the United States, where mortality from ill-defined causes and ill-defined cancer sites has not fallen, it is quite probable that the increase in death rates largely reflects a real increase in cancer risk. There can be little doubt that the rise in lung cancer mortality is a real trend and this has repeatedly been shown to mirror, with an appropriate lag period, previous changes in cigarette consumption. On the other hand, for some countries, such as France, Japan, and Italy, there have been very substantial postwar declines in mortality rates from ill-defined causes, and hence any increase in mortality from diseases for which diagnostic precision is known to have improved must be viewed with some caution. The reductions in CVD mortality have also been accompanied by a rise in the average age at death and a decline in the proportion of all deaths attributable to CVD. There have thus been fewer CVD deaths and these deaths are increasingly postponed to higher ages. This is reflected by the widespread decline in summary indices of premature mortality, such as the age-standardized death rate at ages 35 to 74 years. On the other hand, cancer death rates at these ages have risen in several countries, suggesting that at least some of the "younger" persons "saved" from dying from CVD are now succumbing to cancer. The suggestion that previous cigarette smoking has "claimed" the majority of "saved" lives from CVD is supported by the evidence on mortality trends for major sites of cancer. (The principal site of the disease for which mortality in males at ages 35 to 74 years rose in most countries substantially is lung cancer, which accounts for the vast majority of the rise in overall cancer mortality where it has occurred.) These conclusions would be strengthened if one could demonstrate parallel trends based on incidence data.(ABSTRACT TRUNCATED AT 400 WORDS)