APA 7: TWs Editor. (2023, November 21). The Deadly Effects of High Temperatures in Europe in 2022: Over 70,000 Lives Lost. PerEXP Teamworks. [News Link]
The researchers behind the study, featured in The Lancet Regional Health—Europe, adjusted their initial estimates of the mortality linked to the unprecedented temperatures experienced in Europe during 2022. The study, titled “The effect of temporal data aggregation to assess the impact of changing temperatures in Europe: an epidemiological modelling study,” provides insights into the impact of shifting temperatures on the continent.
In a previous investigation detailed in Nature Medicine, the identical research team utilized epidemiological models to analyze weekly temperature and mortality data across 823 regions in 35 European countries. Their estimate for the number of heat-related premature deaths in 2022 was initially reported as 62,862.
In the earlier study, the researchers acknowledged that relying on weekly data might lead to an underestimation of heat-related mortality. They emphasized the necessity of daily time-series data for a more accurate estimation of the impact of elevated temperatures on mortality.
The aim of the latest study was to establish a theoretical framework for assessing errors associated with the utilization of aggregated data, such as weekly and monthly temperature and mortality time-series. Models relying on temporally aggregated data prove valuable since such data are promptly accessible from institutions like Eurostat, enabling the prompt quantification of health hazards within days of their emergence.
In constructing a theoretical framework, the research team consolidated daily temperatures and mortality records from 147 regions across 16 European countries. Subsequently, they scrutinized and juxtaposed the appraisals of heat- and cold-related mortality at various aggregation levels, encompassing daily, weekly, bi-weekly, and monthly intervals.
The analysis uncovered variations in epidemiological estimations contingent on the time scale of aggregation. Notably, the models based on weekly, two-weekly, and monthly data underestimated the impacts of heat and cold in comparison to the daily model. Furthermore, the extent of underestimation heightened with the lengthening of the aggregation period.
In the specific timeframe of 1998–2004, the daily model projected an annual mortality of 290,104 and 39,434 premature deaths due to cold and heat, respectively. In comparison, the weekly model underestimated these figures by 8.56% and 21.56%, respectively.
Joan Ballester Claramunt, the ISGlobal researcher leading the European Research Council’s EARLY-ADAPT project, emphasizes that although there were minimal differences during extreme cold and heat periods, such as the summer of 2003, the underestimation by the weekly data model was only 4.62%.
Utilizing the new methodological approach based on the theoretical framework, the research team revised the mortality burden associated with the record temperatures in 2022 from their previous study. The recalculation suggests that the heat-related mortality was underestimated by 10.28%, indicating that the actual burden in 2022, estimated with the daily data model, was 70,066 deaths rather than the initially estimated 62,862 deaths.
Exploring short-term temperature effects through weekly data analysis
Ballester explains that, in general, models relying on monthly aggregated data are not deemed useful for accurately estimating the short-term effects of ambient temperatures. However, he highlights that models based on weekly data provide sufficient precision in mortality estimates, making them valuable for real-time practices in epidemiological surveillance. Additionally, such models can inform public policies, including the activation of emergency plans to mitigate the impact of heat waves and cold spells.
In the realm of this research, the use of weekly data proves advantageous, particularly due to bureaucratic challenges that researchers frequently face. These obstacles can hinder or even render impractical the design of large-scale epidemiological studies based on daily data.
In the absence of daily data, Ballester suggests that relying on readily available weekly data, accessible in real-time for Europe, serves as a viable solution, providing a reliable approximation of the estimates derived from the daily data model.
- NEWSPAPER Barcelona Institute for Global Health. (2023, November 21). High temperatures may have caused over 70,000 excess deaths in Europe in 2022. Phys.org. [Phys.org]
- JOURNAL Ballester, J., van Daalen, K. R., Chen, Z.-Y., Achebak, H., Antó, J. M., Basagaña, X., Robine, J.-M., Herrmann, F. R., Tonne, C., Semenza, J. C., & Lowe, R. (2023). The effect of temporal data aggregation to assess the impact of changing temperatures in Europe: an epidemiological modelling study. The Lancet Regional Health – Europe, 100779. [The Lancet Regional Health – Europe]
- JOURNAL Ballester, J., Quijal-Zamorano, M., Turrubiates, R. F. M., Pegenaute, F., Herrmann, F., Robine, J., Basagaña, X., Tonne, C., Antó, J. M., & Achebak, H. (2023). Heat-related mortality in Europe during the summer of 2022. Nature Medicine, 29(7), 1857–1866. [Nature Medicine]