Structure and change in causes of death: An international summary

Abstract Model patterns of the cause structure of mortality at different levels were established for males and females, based on data for 165 national populations. These patterns suggest that the cause of death most responsible for mortality variation is influenza/bronchitis, followed by 'other infectious and parasitic diseases', respiratory tuberculosis, and diarrhoeal disease. Together, these causes typically account for about 60 per cent of the change in level of mortality from all causes combined. Their respective contributions have not depended in an important way on the initial level of mortality. These results - especially tbe importance of the respiratory and diarrhoeal diseases - imply that past accounts may have over-emphasized the role in mortality decline of specific and well-defined infectious diseases and their corresponding methods of control. There is strong statistical support for the suggestion that most of the remainder of mortality variation should be ascribed to changes in cardio-vascular diseases, but that methods of cause-of-death assignment in high-mortality populations have often obscured the importance of these diseases. When death rates from 'other and unknown' causes are held constant, changes in cardio-vascular disease account for about one-quarter of the decline in mortality from 'all causes'.Although the causal factors are poorly established, corroborative results have been demonstrated cross-sectionally in the United States. The composition of the group of populations most deviant from the structural norms is apparently dominated by differentials in the mode of assigning deaths to cardio-vascular disease. However, when broad groups of regions or periods are distinguished, more subtle differences emerge. Controlling mortality level for all causes combined, diarrhoeal diseases are significantly higher in non-Western populations and southern/eastern Europe than in overseas Europe or northern/western Europe. These differences are probably related to standards of nutrition and personal hygiene, but may also reflect climatic factors. Much higher cardio-vascular mortality in overseas European populations than in non-Western populations at similar overall levels probably reflects variation in habits of life. Regional differences in death rates from violence, maternal mortality, respiratory tuberculosis and influenza/pneumonia/bronchitis are briefly noted and commented upon. Cause-of-death structures at a particular level of mortality display some important changes over time. Respiratory tuberculosis and 'other infectious and parasitic diseases' have tended to contribute less and less to a certain level of mortality. They have in part been 'replaced' by diarrhoeal disease, specifically in non-Western populations. These developments reflect an accelerating rate of medical and public health progress against the specific infectious diseases, and a disappointing rate of progress against diarrhoeal disease. Western and non-western populations have shared to approximately the same extent in the accelerating progress against infectious diseases, and developments during the post-war period are more appropriately viewed as an extension of prior trends rather than as radical departures therefrom. For males, cardio-vascular disease and cancer have significantly increased their contribution to a particular level of mortality, while no such tendency is apparent for females. These developments may be related to changes in personal behaviour and in environmental influences whose differential impact on the sexes has been demonstrated in epidemiological studies. Although we have avoided an explicit treatment of age by having recourse at the outset to standardization, certain of the results are apparently reflected in studies of age patterns of mortality. The joint occurrence in non-Western populations and Southern/Eastern populations of exceptionally high death rates from diarrhoeal disease may explain why the 'South' age-pattern, with it high death rates between ages one and five, is often the most accurate referent for use in Latin America and Asia. The fact that the list of populations with the least deviation cause structure is almost exclusively confined to members of the 'West' group of Coale and Demeny may account for the lack of persistent deviation in this group's age patterns. Finally, tbe increasing importance of cardio-vascular disease and neoplasms in cause-of-death structures for males but not females is probably associated with the changing age patterns of male mortality noted by Coale and Demeny.