Heat-Related Deaths Are Falling, but More Efforts Are Needed

Climate change is resulting in heat-related deaths. Last year, 2023, was the hottest year ever recorded globally and the second hottest in Europe. Italy is one of the countries most affected by climate change.
Even though tens of thousands of Europeans die every year because of heat waves, heat-related mortality could have been much worse last year. A recent study published in Nature Medicine evaluated how mortality from heat has changed from 2000 to today, calculating that the summer of 2023, without the adjustments made in the past 20 years, could have been 80% deadlier.
The heat wave of 2003 contributed to what was the hottest summer ever recorded since the sixteenth century. It was estimated to have caused 70,000 deaths in Europe, including 20,000 in Italy. That summer was a turning point in the management of the impact of summer heat waves on health.
Since 2003, the development of heat prevention plans across the continent has increased. In Italy, for example, the National Plan to prevent the effects of heat on health was implemented in 2005. However, there were no measures to verify the effectiveness of these adaptations in reducing heat-related mortality. Raising further doubts, the summer of 2022, which was the hottest summer ever recorded in Europe, seemed to have an overall impact similar to that of the summer of 2003, with an estimated 60,000 deaths, including 18,000 in Italy. In addition, in 2022, Italy also had the highest heat-related mortality rate (295 deaths per million inhabitants).
Mathematical Model
Elisa Gallo, Joan Ballester, and colleagues from the Barcelona Institute for Global Health in Barcelona, Spain, first estimated European heat-related mortality in 2023 and arrived at a total of 47,690 deaths (95% CI, 28,853-66,525). Italy was the third most affected nation in terms of mortality rate, after Greece and Bulgaria. These data contain important demographic differences: Women had a higher heat-related mortality rate than men (in a ratio of 1.55), and people older than 80 years had a mortality rate 8.68 times higher than those aged 65-79 years.
Using data from 823 regions in 35 countries, the researchers evaluated how mortality was related to temperature for four 5-year intervals (from 2000-2004 to 2015-2019). This method allowed them to quantify how temperatures influence mortality in Europe and how this relationship has changed over the past 20 years. It also enabled them to deduce what mortality would have been in previous years if the climatic conditions had been the same as in 2023.
This calculation showed that in Europe, in the early 2000s, a summer like that of 2023 would have caused nearly 86,000 deaths, a number even higher than that in the summer of 2003. Among people older than 80 years, the figure would have doubled. This means that the overall adaptation of European societies has been able to prevent about 80% of the possible heat-related deaths.
Mitigating Health Effects 
The findings of the study align with those of previous models, showing that relative global mortality from heat waves has decreased despite the consistent rise in temperatures. The fact that there are fewer deaths today means that the strategies implemented are effective. The strategies include a heat wave alert system, specific triage and emergency response protocols, identifying vulnerable categories of patients, and offering interventions such as nursing home stays and air conditioner installations. Although the planet’s warming has not been slowed, the impact of this warming is being mitigated.
In May, the Italian National Institute of Health reported a positive trend. “The summer of 2023, characterized by intense heat peaks, however, shows an important reversal of the trend. Data from the Daily Mortality Surveillance System (SiSMG) indicate that excess mortality in cities in Central and Southern Italy has decreased from +16% in 2022 to +4% in 2023. At the same time, in cities in the North, there has been a drop in mortality with an excess of −5% compared to expected. These figures highlight how it is possible to reduce the impact of heat waves on citizens’ health through regulatory, organizational, and informational measures.”
The death tolls are still high, however, which indicates that the current measures are not enough. Future heat waves will be even more frequent and severe than current ones. Improvements in healthcare, such as improved access to care for vulnerable people, public awareness campaigns promoting safe habits during heat waves, progress in occupational medicine and building conditions, the development of heat action plans by public health authorities, and informational campaigns, can be positive factors. It is now necessary to understand which of these interventions have the greatest impact on reducing mortality so that investments can be made in approaches that obtain the best results.
This story was translated from Univadis Italy, which is part of the Medscape professional network, using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
 
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