RESEARCH ARTICLE


Gompertz’ Hazard Law as a Network Principle of Aging



Jakob Korf 1, *, Arthur A. Sas2
1 Center of Psychiatry, University of Groningen, UMC Groningen, 9700 RB Groningen, The Netherlands
2 Department of Epidemiology, Unit of Genetic Epidemiology and Bioinformatics, University of Groningen, UMC Groningen, The Netherlands


© 2019 Korf and Sas.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Biological Psychiatry. University of Groningen UMCG, 9700 RB Groningen, The Netherlands; Tel: 031 592 541974; Email: j-korf@home.nl


Abstract

Background:

Life-spanning population survivorship curves (the number of survivors versus age) are conventionally regarded as a demographic issue. Most often, the term hazard, the relative mortality per age-interval, is used as a typical survivorship parameter. Population survivorship curves are construed from cross-sectional data (single event per individual; here, mortality).

Objective:

We tested (quantitatively) how Gompertz’ law describes the mortality pattern of a wide variety of organisms, some of them fed with lifespan affecting diets. Moreover, we tested (semi-quantitatively) whether Gompertz’ law describes the disintegration of a (biological) small-world network.

Methods:

The Gompertz tests, explored in demographic data of humans (male/female) and 4 animal species (mice, honeybees, fruit flies, houseflies), were analyzed with conventional software. The Gompertz law was examined in a small-world network model.

Results:

Gompertz' law applies to all cohorts; thus, with or without exposure to experimental conditions. It describes in all cohorts old-age slowing of mortality. Gompertz’ law is compatible with a gradual and random increase of connections in the network model.

Conclusion:

Old-age deceleration of mortality is a characteristic of many populations. Aging has to be understood as a lifetime increasing of excitatory or, alternatively, of decreasing inhibitory (biological) connections, thereby facilitating pathogenic mechanisms.

Keywords: Aging, Animal species, Deceleration of mortality, Gompertz’ hazard law, Modeling, Small-world network.