The Triumph of Cohort Effects in the Explanation of Mortality Change: A New Age-Period-Cohort Analysis of Adult Cause-Specific Mortality in the United States

Yang Yang, University of Chicago

This study examined the temporal changes in U.S. adult mortality by cause of death and sex over a 40-year period in the second half of the 20th century. It applied the Intrinsic Estimator to log-linear APC models to simultaneously account for age, period, and cohort variations in mortality rates for four leading causes of deaths – heart disease, stroke, lung cancer, and female breast cancer. The results show that the large mortality reductions since the late-1960s continued well into late-1990s and that these reductions were predominately contributed by cohort effects. Cohort effects are found to differ by specific causes of death examined, but they generally show substantial survival improvements. Implications of these results are discussed with regard to epidemiological transition theory, the theory of technophysio evoluation, differential cohort accumulation of health capital and lifetime exposures to socioeconomic and behavioral risk factors, and period changes in diagnostic techniques and medical treatment.