Climate Change: Heat-induced heart attack risk on the rise
14 Mar 2019 | Source: HelmholtzZentrum München - German Research Center for Environmental Health
Heart attack, or myocardial infarction, is the number one cause of death worldwide. A study published in the European Heart Journal by scientists at Helmholtz Zentrum München and colleagues from a range of other Bavarian institutions shows that the risk of suffering a heat-induced heart attack has increased significantly in recent years. During the same period of time, no comparable changes in cold weather heart attack risks have been recorded.
The environment can have a major effect on the human cardiovascular system. It has long been assumed that severe spikes in temperature increase the risk of heart attack. “In the case of very high and very low temperatures in particular, this has been clearly demonstrated. In this latest study, we wanted to see to what extent the heat and cold-related heart attack risk has changed over the years,” explains Dr. Kai Chen, researcher at the Institute of Epidemiology at Helmholtz Zentrum München.
Together with colleagues from Ludwig Maximilian University in Munich, Augsburg University Hospital and Nördlingen Hospital, he examined data from the Myocardial Infarction Register Augsburg. The study looked at more than 27,000 heart attack patients between 1987 and 2014. The average age of the patients studied was around 63, 73% were men and about 13,000 ended in the death of the patient. The individual heart attacks were compared against meteorological data on the day of the attack and adjusted for a range of additional factors, such as the day of the week and socioeconomic status. The key finding from the study, explains Chen was that, “Over a period of 28 years, we found that there has been an increase in heat-induced heart attack risk in recent years.”
In order to demonstrate this, the researchers compared data from 1987 to 2000 with data from 2001 to 2014. “Our analysis showed that, over the last few years, the risk of heat-induced heart attack with increasing average daily temperature has risen compared to the previous investigation period,” explains Chen. Individuals with diabetes or hyperlipidaemia were particularly at risk over the latter period. The researchers suspect that this is partly a result of global warming, but that it is also a consequence of an increase in risk factors such as diabetes and hyperlipidaemia, which have made the population more susceptible to heat.
Is climate change a heart attack risk?
“Our study suggests that greater consideration should be given to high temperatures as a potential trigger for heart attacks – especially in view of climate change,” explains lead researcher Dr. Alexandra Schneider. “Extreme weather events, like the 2018 heat waves in Europe, could in future result in an increase in cardiovascular disease. At the same time, there is likely to be a decrease in cold-related heart attacks here in Germany. Our analysis suggests a lower risk in the future, but this lower risk was not significant and very cold days will continue to represent a potential trigger for heart attacks.” To what extent increases in heat-related heart attacks will be counterbalanced by a decrease in cold-related heart attacks is not yet clear, explains the epidemiologist. Her group is currently performing extrapolations aimed at modelling this change in risk both in scenarios where the world meets the Paris Agreement’s 1.5 °C and 2 °C targets and in scenarios where these targets are missed.
In addition, the researchers are also planning to corroborate their findings by carrying out additional, multicenter studies.
The Myocardial Infarction Register Augsburg was set up in 1984 by Helmholtz Zentrum München as part of the MONICA project. Since then it has collected data on all new heart attacks in people aged between 25 and 74 admitted to one of the eight participating hospitals, whose primary place of residence is within the defined catchment area. Because of the very high participation levels among heart attack patients and the high scientific value of the research findings from the 1995 MONICA project, the register has continued to record data on heart attacks in the region as part of a project entitled Kooperative Gesundheitsforschung in der Region Augsburg (KORA). Since 2000, the German Federal Ministry of Health has been funding data collection for the KORA Myocardial Infarction Register, with the aim of incorporating the most important research results into federal government health reporting. In order to gain additional insights into heart attacks, their consequences and the therapies used to treat them in older people, in 2009, the upper age limit was increased to 84. The KORA Myocardial Infarction Register is based at Augsburg University Hospital – the largest hospital in the study catchment area.
As German Research Center for Environmental Health, Helmholtz Zentrum München pursues the goal of developing personalized medical approaches for the prevention and therapy of major common diseases such as diabetes mellitus, allergies and lung diseases. To achieve this, it investigates the interaction of genetics, environmental factors and lifestyle. The Helmholtz Zentrum München has about 2,300 staff members and is headquartered in Neuherberg in the north of Munich. Helmholtz Zentrum München is a member of the Helmholtz Association, a community of 19 scientific-technical and medical-biological research centers with a total of about 37,000 staff members.
The Institute of Epidemiology (EPI) assesses genetic, environmental and lifestyle risk factors which jointly determine the occurrence of major chronic diseases. The focus is on the development and progression of metabolic, respiratory and allergic diseases, as well as heart diseases and mental health. The goal is to understand the molecular underpinning of disease better and to translate this knowledge into personalized approaches of prevention as well as polices to improve health. Research builds on the unique resources of the KORA cohort, the KORA myocardial infarction registry, and the KORA aerosol measurement station. Aging-related phenotypes have been added to the KORA research portfolio within the frame of the Research Consortium KORA-Age. Moreover, the institute makes use of the birth cohorts GINI and LISA. It plays a leading role in the planning and setting up of the German National Cohort and builds the NAKO biorepository.