Late-life mortality deceleration

Concept in demography and gerontology

Late-life mortality deceleration

Illustration of the Gompertz curve, which is used to model mortality rates.

Late-life mortality deceleration is a phenomenon observed in demography and gerontology where the rate of increase in mortality slows down at advanced ages. This concept challenges the traditional Gompertz–Makeham law of mortality, which suggests that mortality rates increase exponentially with age.

Overview

The concept of late-life mortality deceleration suggests that as individuals reach very old ages, the increase in their mortality rate slows down, and in some cases, mortality rates may even plateau. This observation has been made in various species, including humans, and has significant implications for understanding the biology of aging and the limits of human lifespan.

Theoretical Background

The traditional Gompertz–Makeham law of mortality posits that the force of mortality increases exponentially with age. However, empirical data from studies on human populations and other species have shown deviations from this model at advanced ages. The deceleration of mortality rates at late life stages suggests that the biological processes governing aging and death may change as organisms reach extreme ages.

Biological Explanations

Several hypotheses have been proposed to explain late-life mortality deceleration:

• Heterogeneity in frailty: Populations consist of individuals with varying levels of frailty. Those who survive to very old ages may represent a select group with lower frailty, leading to a deceleration in mortality rates.

• Evolutionary theories: Some evolutionary biologists suggest that natural selection pressures decrease with age, leading to a deceleration in mortality rates as the force of selection weakens.

• Repair mechanisms: It is hypothesized that organisms may have evolved mechanisms to repair damage more effectively at older ages, contributing to a slowing of mortality rate increases.

Implications for Human Longevity

Understanding late-life mortality deceleration is crucial for predicting human longevity and the potential limits of the human lifespan. It challenges the notion of a fixed maximum lifespan and suggests that improvements in health care and living conditions could further extend human life expectancy.

Related Pages

• Gompertz–Makeham law of mortality
• Demography
• Gerontology
• Human longevity
• Biology of aging