摘要:Heart disease and cancer are the first and second leading causes of death in the United States. Age-standardized death rates (risk) have declined since the 1960s for heart disease and for cancer since the 1990s, whereas the overall number of heart disease deaths declined and cancer deaths increased. We analyzed mortality data to evaluate and project the effect of risk reduction, population growth, and aging on the number of heart disease and cancer deaths to the year 2020. We used mortality data, population estimates, and population projections to estimate and predict heart disease and cancer deaths from 1969 through 2020 and to apportion changes in deaths resulting from population risk, growth, and aging. We predicted that from 1969 through 2020, the number of heart disease deaths would decrease 21.3% among men (-73.9% risk, 17.9% growth, 34.7% aging) and 13.4% among women (-73.3% risk, 17.1% growth, 42.8% aging) while the number of cancer deaths would increase 91.1% among men (-33.5% risk, 45.6% growth, 79.0% aging) and 101.1% among women (-23.8% risk, 48.8% growth, 76.0% aging). We predicted that cancer would become the leading cause of death around 2016, although sex-specific crossover years varied. Risk of death declined more steeply for heart disease than cancer, offset the increase in heart disease deaths, and partially offset the increase in cancer deaths resulting from demographic changes over the past 4 decades. If current trends continue, cancer will become the leading cause of death by 2020.