Related Experiment Video
Updated: Apr 14, 2026
10:00
Measurement of Lifespan in Drosophila melanogaster
Published on: January 7, 2013
35.9K
Intrinsic and extrinsic mortality reunited
Jacob J E Koopman1, Maarten J Wensink2, Maarten P Rozing3
1Department of Gerontology and Geriatrics, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands; Leyden Academy on Vitality and Ageing, Rijnsburgerweg 10, 2333 AA Leiden, the Netherlands.
Experimental Gerontology
|April 29, 2015
Summary
Aging is driven by both internal and external factors interacting, not just aging itself. Environmental interventions can modify the aging process, suggesting aging is not inevitable.
Area of Science:
- Gerontology
- Demography
- Environmental Health
Background:
- Intrinsic mortality (aging-related) and extrinsic mortality (environmental hazards) are traditionally separated to study aging.
- Both mortality types exhibit an exponential age-related increase, challenging traditional separation.
- Aging theories propose that combined intrinsic and extrinsic stressors drive mortality risk.
Purpose of the Study:
- To challenge the traditional separation of intrinsic and extrinsic mortality.
- To propose a new framework for understanding aging and mortality based on stressor interaction.
- To highlight the role of environmental factors in modulating aging.
Main Methods:
- Review of existing theories on aging and mortality.
- Analysis of epidemiological and biological data on aging stressors.
- Conceptual framework development integrating intrinsic and extrinsic factors.
Main Results:
- Intrinsic and extrinsic mortality share an exponential age-related pattern.
- Combined intrinsic and extrinsic stressors, not their separation, better explain aging and death.
- Controlling both intrinsic and extrinsic stressors can mitigate aging.
Conclusions:
- Aging and death result from the complex interaction of intrinsic and extrinsic stressors.
- Classifying mortality solely as intrinsic or extrinsic is an oversimplification.
- Aging is a malleable process influenced by environmental interactions, not an inevitable outcome.
Keywords:
AgingExtrinsic mortalityGene–environment interactionIntrinsic mortalityPartitioning of mortalityMore Related Videos
Related Concept Videos
01:20Actuarial Approach
383
The actuarial approach, a statistical method originally developed for life insurance risk assessment, is widely used to calculate survival rates in clinical and population studies. This method accounts for participants lost to follow-up or those who die from causes unrelated to the study, ensuring a more accurate representation of survival probabilities.
Consider the example of a high-risk surgical procedure with significant early-stage mortality. A two-year clinical study is conducted,...
Consider the example of a high-risk surgical procedure with significant early-stage mortality. A two-year clinical study is conducted,...
383
01:22Life Tables
667
A life table is a statistical tool that summarizes the mortality and survival patterns of a population, providing detailed insights into the likelihood of survival or death across different age intervals within a cohort. By organizing data on survival probabilities and mortality rates, life tables offer a clear snapshot of population dynamics over time. They are extensively used in demography, public health, actuarial science, and ecology to analyze life expectancy, design health interventions,...
667
01:11Hazard Rate
515
The hazard rate, also known as the hazard function or failure rate, is a statistical measure used to describe the instantaneous rate at which an event occurs, given that the event has not yet happened. From a probabilistic perspective, it represents the likelihood that a subject will experience the event in a very small time interval, conditional on surviving up to the beginning of that interval. In terms of frequency, the hazard rate can be viewed as the ratio of the number of events to the...
515
01:17The Extrinsic Apoptotic Pathway
9.4K
The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
9.4K
01:24Kaplan-Meier Approach
757
The Kaplan-Meier estimator is a non-parametric method used to estimate the survival function from time-to-event data. In medical research, it is frequently employed to measure the proportion of patients surviving for a certain period after treatment. This estimator is fundamental in analyzing time-to-event data, making it indispensable in clinical trials, epidemiological studies, and reliability engineering. By estimating survival probabilities, researchers can evaluate treatment effectiveness,...
757
01:31The Intrinsic Apoptotic Pathway
9.3K
Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
9.3K