Global challenges in aging: insights from comparative biology and one health

Abstract

The well-being of wildlife populations, ecosystem health, and human health are interlinked, and preserving wildlife is crucial for sustaining healthy ecosystems. Wildlife numbers, and in particular avian populations, have steeply declined over the past century, associated with anthropogenic factors originating from industry, urbanization, changing land use, habitat loss, pollution, emerging diseases, and climate change. All these factors combine to exert increasing stress and impair health for both humans and wildlife, with diminished metabolic, immune, and reproductive function, deteriorating overall health, and reduced longevity. The "toxic aging coin" suggests that these stressors may have dual impacts on aging-they can accelerate the aging process, and older individuals may struggle to cope with pollutants compared to younger ones. These responses are reflected in the health and productivity of individuals, and at a larger scale, the health and ability of populations to withstand disturbances. To understand the potential risk to health over the lifespan, it is important to articulate some of these global challenges and consider both their impacts on aging populations and on the aging process. In this review, we use the toxic aging coin and One Health conceptual frameworks to examine the interconnected health of humans, wildlife, and ecosystems. This exploration aims to develop proactive approaches for optimizing wildlife and human health.

Keywords: ecosystem resilience; exposome; human health; one health; pollution; sustainability; toxic coin; wildlife health.

FIGURE 1

Comparison of the safety and environmental impacts, as measured by greenhouse gas emissions for various sources of energy (from Our World in Data, available through CC-BY by the authors, Ritchie and Rosner).

FIGURE 2

Visualization of the growth in exports globally shows a sharp increase in the past 70 years (from OurWorldinData.org/internationaltrade; https://ourworldindata.org/trade-and-globalization#).

FIGURE 3

Estimated probabilistic projections for world population (from: United Nations, 2024; https://esa.un.org/unpd/wpp/Graphs/DemographicProfiles/; https://esa.un.org/unpd/wpp/Graphs/Probabilistic/POP/TOT/).

FIGURE 4

(A) Number of children and aging adults as a percentage of the global populations (from United Nations World Population Prospects (2024); (B) Global increase in aging individuals (from US Census Bureau, 2016).

FIGURE 5

Global distribution of predicted life expectancy for both genders at birth 2090-2095 (from UN Population Division; https://population.un.org/wpp/Maps/6.1_Life%20Expectancy%20-%20Both%20Sexes/e0Total-LowRes-2090.png).

FIGURE 6

Determinants of health for individuals in the 21st century (percentages illustrate relative impacts, also influenced by local climate, water and air quality, and pollution (from Ottinger and Geiselman, 2023).

FIGURE 7

Threats to wildlife have varied sources, including agriculture, environmental chemicals, habitat loss, pollutants, and climate change (Ritchie and Roser, 2021).

FIGURE 8

Conceptual example of the dynamic linkages between humans, wildlife, and domestic species within the ecosystem. In this example, deforestation caused by humans causes stress to wildlife from loss of habitat, which causes an increase in shed viruses that can spillover to domestic animals, who then pass viruses on to humans (from Ottinger and Geiselman, 2023).

FIGURE 9

An individual’s Exposome is impacted by internal and personal choice, external and situational factors, and the biological responses to these factors throughout the lifespan (from Ottinger and Geiselman, 2023).