Heterogeneity in the Strehler-Mildvan General Theory of Mortality and Aging

Hui Zheng, Duke University
Kenneth C. Land, Duke University

This study intends to examine and further develop the Strehler-Mildvan general theory of mortality and aging. We tested three predictions from the SM theory by examining the age dependence mortality patterns for 46 countries over the period of 1955-2003. By using descriptive analyses and semiparametric group-based trajectory models, this study finds that: (1) the SM correlation exists but is not constant; (2) within the SM framework, the implied upper bounds on the human life span appear to be variable over time; (3) longevity trajectories are not homogeneous among the countries. Moreover, an inverse relationship between the national environment parameter D and the rate of physiological decline parameter B is found, that is, when the national environment becomes worse, the more B decreases, which suggests the “survival trade off” theory may be correct. These findings indicate that the Strehler-Mildvan theory needs to be generalized to incorporate heterogeneity among human populations.