A macrodynamic analysis of changes in mortality indexes in the United States 1946-75: some preliminary results

This paper extends earlier research by Brenner and by Land and Felson on the specification and estimation of macrodynamic structural-equation models to explain changes in American mortality indexes as a function of exogenous changes in societal conditions (social, demographic, economic, and health care). After reviewing the record of annual changes in several general and cause — specific mortality indexes for the post-World War II United States, patterns of temporal covariation in the indexes are discussed and some tentative structural-equation models are described. Among other findings, these models indicate: (1) that changes in the age structure of the American population have substantial impacts on changes in mortality rates for diseases of the respiratory and circulatory systems as well as on deaths due to cirrhosis of the liver, accidents, and violence; (2) that the infective and parasitic diseases mortality rate is more closely related to per capita public health expenditures than to improvements in the general level of living in this post — war period; (3) that the business cycle, as indexed by the unemployment rate, has significant impacts on the cardiovascular, accident, and violence mortality rates; (4) that Brenner's finding of a positive association of an increase in the unemployment rate with an increase in cardiovascular diseases mortality two to three years later is partially mediated by an increase in per capita cigarette consumption during the economic recovery following a recession; (5) that an increase in the per capita level of cigarette consumption increases the respiratory systems mortality rate; (6) that both the general and the respiratory neoplasms mortality rates are more strongly affected by long-term moving averages of annual per capita levels of cigarette consumption than by single-years levels; (7) that the level of the degenerative diseases mortality rate is positively affected by an increase in per capita liquor consumption and negatively affected by an increase in health care utilization; (8) that the percentage of all vehicles traveling on highways at high speed is the exposure index most closely associated (of several that were studied) to the motor vehicle accident mortality rate; (9) that the levels of the maternal and infant mortality rates are positively related to an increase in the fertility rate (exposure) and negatively related to those advances in health care services associated with hospital births; (10) that the accuracy with which short-term changes in the crude mortality rate can be predicted from a knowledge of cause-specific mortality rates and how the latter are affected by societal conditions is effectively limited by the degree of accuracy of predictions of the respiratory diseases mortality rate because of its volatile influenza, pneumonia, and bronchitis component; and (11) that short-term changes in the life expectancy index can be somewhat more accurately predicted from such knowledge. Although most of these relationships have been noted before in mortality studies, only a small fraction have been studied in a macrodynamic structural-equation models context. These findings thus constitute a baseline of statistical evidence which can be explored in future research.