Chapter 2 - Mortality characteristics

Abstract

This chapter reviews survival curves and related data and temporal pattern of food intake. The mortality characteristics of populations have been, and most probably will continue to be, widely used in the study of aging. Data, relating to calendar age and mortality of a population or a cohort, are collected in what are termed “life tables.” There are two kinds of such tables: period life tables and cohort life tables. Survival curves are frequently used to create graphic presentations of life table mortality data. An example of survival curves obtained in the analysis of data from a caloric restriction (CR) study on male F344 rats shows that CR increases both the median length of life and the maximum length of life of the population. However, an increase in median length of life does not necessarily mean that aging processes have been slowed; prevention of premature death would increase the median length of life even if the aging processes were not affected. Reduction of energy intake rather than the temporal pattern of food intake is responsible for the life-extending action of CR. The chapter also discusses Gompertzian analyses and the age of initiation and duration of CR.