According to a study by the Barcelona Global Health Institute, the number of deaths in Europe due to rising temperatures in the summer of 2022 may exceed 70,000.
The authors of the study, published in the journal The Lancet Regional Health Europe, reviewed preliminary upward revisions to estimates of the number of deaths related to record temperatures in 2022 across the continent.
Previous estimates and lower figures
In a previous study by the same team, published in the journal Nature Medicine, the team used an epidemiological model to analyze weekly temperature and mortality data for 823 regions in 35 European countries to estimate the number of heat-related deaths in 2022. The number of premature deaths was 62,862.
In the study, the authors acknowledge that using weekly data is expected to lead to an underestimation of heat-related mortality and note that daily time series data are needed to accurately estimate the impact of heat on mortality.
The goal of this new study is to develop a theoretical framework capable of measuring errors resulting from the use of aggregated data, such as weekly and monthly temperature and mortality time series.
As a press release posted on the institute’s website points out, models based on time-aggregated data are useful because aggregated data are available in real time from agencies such as Eurostat, helping to detect health risks within days of their emergence. To quantify.
Accurate estimating tool
To establish a theoretical framework, the research team collected daily temperature and mortality records for 147 regions in 16 European countries, then analyzed and compared heat- and cold-related mortality estimates at different aggregation levels; daily, weekly , biweekly and monthly.
The analysis showed differences in estimates based on the time frame in which they were collected. In particular, we find that weekly and monthly models underestimate the effects of heat and cold compared with daily models, and that the degree of underestimation increases with the length of the collection period.
Specifically, between 1998 and 2004, the daily model estimated annual cold- and heat-related deaths at 290,104 and 39,434, respectively, while the weekly model underestimated these figures by 8.56% and 21.56%, respectively.
The team used this theoretical framework to review the mortality burden from record temperatures in 2022 from previous studies. Based on calculations using the new method, the actual burden of heat-related deaths in 2022 estimated using the daily data model is 70,066, rather than 62,862 originally expected.