High Temperatures Have Short-Term Impact on All Major Causes of Death, Including Suicide

Graph 1: Association between temperature (x-axis) and relative risk of all-cause mortality (y-axis) for the 1968-2016 period (U-shaped relationship) Temperature and mortality are linked. There is a short-term increase in mortality when temperatures are at their hottest or coldest - a phenomenon known as a "U-shaped relationship”. Inserm researchers at the Institute for Advanced Biosciences (Inserm/Université Grenoble Alpes/CNRS) and the Inserm Epidemiology Center on Medical Causes of Death (CépiDc) have sought to determine the extent to which this relationship between temperature and mortality varies according to the medical cause of death; for what causes of death is the effect of hot temperatures the highest; and whether there are signs of adaptation to extreme temperatures - an important question in the context of climate change. This new study, based on all of the deaths having occurred in France over a 49-year period, confirms the U-shaped relationship (see Graph 1 below) observed between temperature and the majority of the causes of death considered. However, an exception has been observed for death from suicide, which rose steadily in line with the temperature, without the increased risk at cold temperatures observed for the other causes of death. Furthermore, the effect of temperatures at either extreme on all-cause mortality seems to have reduced slightly during this period, which could mean that our society is adapting better. This research has been published in the American Journal of Epidemiology .