A new study published in the journal eBioMedicine aims to predict the extent to which climate change may affect cardiovascular disease (CVD) mortality risk in China.
Study: Projection of burden of heat-related cardiovascular mortality attributable to human-induced climate change in China. Image credit: Piyaset / Shutterstock.com
Climate change and CVD
Current estimates indicate that approximately 19 million people die each year due to cardiovascular disease, five million of whom reside in China. In addition, CVD causes more than 390 million disability-adjusted life years (DALYs) worldwide.
Due to climate change, the global temperature at the earth’s surface has increased by 1.15 °C above that of the pre-industrial era. Previous studies have reported a negative effect of climate change on age-, sex- and cause-specific total mortality, as well as deaths due to cardiovascular disease.
Heat affects the cardiovascular system in many ways, including salt and water excretion as sweat, higher cholesterol levels, and hemodynamic stress. In addition, the heat associated with climate change may increase the risk of atherosclerotic thrombosis of the heart and cerebral vessels and, as a result, the rate of stroke and heart attacks.
About the study
The present study attempted to predict CVD mortality associated with climate change in a Chinese setting. Current temperatures were measured at 161 disease surveillance points (DSPs).
These projections were based on the Coupled Model Intercomparison Project Phase 6 (CMIP6), which is part of the World Climate Research Program (WCRP). The WCRP considers natural climate change and the combined scenario with natural and anthropogenic climate impacts.
A total of 22 General Climate Models (GCMs) were used to determine projected temperatures from 2010 to 2100 under both anthropogenic and natural scenarios. Human-caused scenarios were calculated based on the difference between combined and natural impacts.
Recognizing that economic and social change is closely related to climate change, the Intergovernmental Panel on Climate Change (IPCC) has presented a series of integrated scenarios that combine common socio-economic pathways (SSPs) and climate proxy aggregation pathways (RCPs).
Study findings
The mean annual temperature in DSPs ranged from 12.6 to 28.4 °C, during which approximately 330,000 deaths from cardiovascular disease occurred.
Under natural conditions, summer temperatures in China would not change significantly. Similarly, in this scenario, the rate of heat-related CVD deaths would decrease by 0.5% in the 2090s compared to 2010 CVD death rates.
In contrast, summer temperatures increased by 5–6 °C under the combined scenarios, depending on the region. The projected fraction of CVD mortality in the 2090s increased from 10% to 30%, depending on the modeled scenario.
The mortality rate among patients with cardiovascular disease followed a J-shaped curve beyond a critical minimum temperature. The most significant increase over the baseline temperature was in South and East China.
The proportion of heat-related deaths from CVD with human-induced climate change continued to increase during each decade from about 31% in the 2010s to about 70–90% in the 2090s under different scenarios.
People found to be more vulnerable to heat-related CVD mortality included people living in rural areas, people with lower education levels, stroke patients, women, the elderly, and those living in southern and eastern China. Importantly, people with lower levels of education are more likely to work outdoors, have unequal access to health care, and be diagnosed with chronic diseases.
conclusions
“This study provides evidence that human activities will enhance the future burden of heat-related cardiovascular mortality.”
Anthropogenic climate change resulting in CVD deaths could account for 90% of excess heat-related mortality by 2090. At the same time, the CVD burden associated with natural climate change may not change significantly. However, the study’s findings underscore the importance of curbing carbon emissions to prevent further global warming eventually.
“Active adaptation and mitigation measures for future warming could have significant health benefits for patients with cardiovascular disease.”
Future studies are needed to identify populations and groups most at risk of climate-related health impacts and the different types of risk that may be associated with global climate change. These data will help implement comprehensive and sensitive public health policies to ultimately achieve environmental goals.
Journal Reference:
- Zhu, Q., Zhou, M., Sakhvidi, MJZ, et al. (2024). Projecting burden of heat-related cardiovascular mortality attributable to human-induced climate change in China. eBioMedicine. doi:10.1016/j.ebiom.2024.105119.
