The rapid aging of the worldwide population is anticipated to grow to be a big social problem in the long run. A recent Npj Climate and Atmospheric Science study investigates the role of temperature rise on mortality rates within the elderly population in China.

Study: Projection of temperature-related mortality among the many elderly under advanced aging and climate change scenario. Image Credit: Ljupco Smokovski / Shutterstock.com

Background

Two of essentially the most interlinked concerns of the twenty first century are population aging and rapid climate change. Climate change contributes to rising global temperatures, which has been correlated with higher morbidity and mortality rates. Climate change also results in biodiversity and ecosystem changes that may have immediate or delayed impacts on human health.

Previous studies on temperature-related mortality as a consequence of climate change have shown that the risks imposed by cold and warm temperatures are usually not the identical in relation to age. For instance, in comparison with higher temperatures, low temperature causes more global non-communicable deaths.

A recent survey revealed that as in comparison with heart-related issues, a more significant variety of older individuals died as a consequence of cold-associated conditions. These findings imply the importance of mitigating the effect of cold temperatures on advanced aging to combat potential severe public health consequences.

Aging has accelerated as a consequence of increased life expectancy and reduced fertility rates. The United Nations World Population Outlook 2022 reported that the proportion of the elderly population will globally increase by 60% from 2022 to 2050.

In keeping with a 2021 evaluation, the aging rate of the Chinese population has increased by 14%, which is anticipated to further increase to 21% by 2025. This increase within the aging rate of China’s elderly population will likely proceed until 2055 after which stabilize. As a result of increasing life expectancy, advanced aging could grow to be a big issue in China, particularly within the second half of the twenty first century.

A rise within the variety of heat-related deaths has been documented in China and is anticipated to proceed to rise as a consequence of global warming. Although many studies have investigated the consequences of climate on mortality rates, these studies haven’t considered individuals over 80 or 90 years of age, a lot of whom are most affected by non-optimal temperatures.

Concerning the study

The present study analyzed the direct and indirect effects of temperature on the oldest group in China. This study considered population data from Nantong City, China, because it has the best proportion of older people amongst 340 cities.

To find out how temperature change affects this population, all-cause mortality and temperature/humidity data were collected between January 1, 2012, and December 31, 2017. This data was categorized into three groups based on age, including 65-79 years (young-old), 80-89 years (middle-old), and 90+ years (oldest-old).

The effect of temperature on the aging population was determined using 27 global climate models which might be included within the Coupled Model Intercomparison Project Phase 6 (CMIP6) and 4 emission scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5).

Study findings

The minimum mortality temperature (MMT) for the elderly population in Nantong increased with age, which suggests that climate change and aging increase heat-related mortality and reverse the trend of cold-related mortality. 

Based on the belief that the population demographics of Nantong remained constant, the study findings indicate that climate change, which is defined as a rise in extremely high temperatures (high RR) and a decrease in moderately low temperatures (low RR), will proceed to cause a rise in mortality. Thus, future studies must assess whether climate change will influence positive or negative net annual mortality related to temperature.

Consistent with previous reports, the study findings reveal that the range of high temperatures was narrower in comparison with low temperatures. Moreover, many of the minimum temperature-related mortality was related to the local temperature percentile.

Typically, the association between temperature and mortality depends on quite a few social aspects, including urbanization rate, the region’s development, usage of air con, central heating, economic performance, and population age structure. 

The population-attributable fraction (PAF) of cold and warmth varied across different populations and climate change scenarios. The interactive effect of advanced age and increased temperature was even higher than the buildup of their independent effects.

Since cold-related mortality linked to advanced aging will proceed to extend or remain constant, health risks related to low temperatures must even be considered.

Conclusions

Advanced aging accelerates heat-related mortality; due to this fact, governments throughout the world must give attention to reducing greenhouse gas emissions to mitigate global warming, which can reduce heat-related mortality within the oldest old age group. The study findings emphasize the importance of formulating each cold and warmth prevention policies based on local population structure and the extent of climate change.

Journal reference:

• Huang, Y., Li, C., Liu, D. L., & Yang, J. (2023) Projection of temperature-related mortality among the many elderly under advanced aging and climate change scenario. Npj Climate and Atmospheric Science 6(1);1-10. doi:10.1038/s41612-023-00487-z