The heatwave that swept across Switzerland in late June appears to have caused a modest increase in deaths among older people. Mortality among those aged 65 and over exceeded official projections during the week of June 22nd-28th, though it remained well below the levels recorded during the country’s record-breaking heatwave in 2003.
According to weekly figures from the Federal Statistical Office (FSO), 1,278 people aged 65 or over died during the week. That was 175 more than the 1,104 deaths expected based on historical trends.
The last heatwave of comparable intensity occurred in the summer of 2015, Switzerland’s second-hottest summer since records began. The excess mortality recorded this year is broadly comparable to that seen during a moderate to severe influenza season.
The figures cover everyone aged 65 and over, a standard public-health threshold. But the category is broad and misleading. The risk is concentrated among the oldest adults, particularly those over 80 or 85.
Heat is rarely listed as the cause
Heat is seldom recorded as the direct cause of death, just as many other environmental risk factors are not. Instead, heat-related mortality is estimated statistically by comparing reported deaths with daily temperature data, a measure known as excess mortality.
The work is carried out by the Swiss Tropical and Public Health Institute (Swiss TPH) on behalf of the federal government. Based on its estimates, heat has caused around 500 additional deaths each summer in Switzerland in recent years. During the exceptional summer of 2003, the institute estimated roughly 1,400 excess deaths attributable to heat. In 2015, the figure was 747.
Adaptation appears to be helping
Researchers say the decline in heat-related deaths since 2015 suggests that adaptation measures are reducing the health impact of extreme temperatures.
Following the deadly 2003 heatwave, federal and cantonal authorities introduced heat warning systems, public information campaigns and heatwave action plans aimed at protecting vulnerable groups. Care homes and healthcare providers now monitor elderly and medically vulnerable people more closely during periods of extreme heat, while public advice encourages people to stay hydrated, avoid strenuous activity during the hottest part of the day and check on older relatives and neighbours.
Nevertheless, the latest heatwave still placed pressure on parts of the healthcare system. The University Hospital Zurich and emergency departments in Ticino reported a marked increase in patients suffering from heat-related illnesses during the hot spell, according to a survey by Keystone-ATS, reported RTS.
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