Study of over 46 million deaths globally reveals who is most at risk from non-optimum temperatures and which diseases are most affected
Credit: Comstock from Photo Images
A large international study of the health impacts of cold and heat has just been published in The Lancet’s eClinicalMedicine journal, finding that 4.4 percent of deaths between 2000 and 2019 can be attributed to short-term exposure to non-optimum temperatures across ten countries or territories. The study is one of the most comprehensive multi-country analyses examining how temperature-related mortality risks vary across diseases, age groups, and sexes.
Led by Dr Bo Wen and Professor Yuming Guo from the School of Public Health and Preventive Medicine, the study analysed over 46 million deaths from nine causes across ten countries/territories, revealing the demographics of those most affected and the diseases most likely to occur. The study identified three distinct exposure-response patterns: higher risks from cold than from heat for most causes; equivalent risks from cold and heat for respiratory mortality; and higher risks from heat for injuries and external causes.
The diseases most affected were mental health disorders (6.53 percent), nervous system diseases (6.4 percent) and cardiovascular conditions (5.71percent) Importantly, the research reveals the risks were not the same for everyone, according to Dr Wen.
“We found that older adults were more vulnerable to cold-related nervous system diseases and neoplasms (cancers), while younger individuals were more affected by heat-related risks for injuries and external causes,” he said. “This study shows that public health strategies need to move beyond general warnings about heat or cold and instead focus on specific diseases and vulnerable groups.”
The study analysed associations between temperature and mortality in 1117 locations from ten countries or territories (Australia, Brazil, Canada, Chile, Mexico, New Zealand, Philippines, South Korea, Taiwan, and Thailand) from 2000 to 2019. Across the study period (approximately two decades, varying by country), the researchers estimated that 2·03 million deaths were attributable to non-optimum temperatures, corresponding to 4·38 percent of all deaths. For most causes of death, cold temperatures accounted for the largest proportion of mortality. However, for deaths related to infectious as well as injury and external causes, heat exposure contributed to the majority of the mortality.
According to Professor Guo, this is the largest multi-country study to date to characterise cause-, age-, and sex-specific mortality risks associated with non-optimum temperatures. “Critically, differences in temperature-related mortality risks were observed between subgroups of age and sex,” he said. “With the impacts of cold and heat varying across causes of death.”
Read the full paper in the Lancet’s eClinicalMedicine journal: Mortality risk due to non-optimum temperatures by cause of death, age, and sex: a multi-country time-series study.
About Monash University
Monash University is Australia’s largest university with more than 80,000 students. In the 60 years since its foundation, it has developed a reputation for world-leading high-impact research, quality teaching, and inspiring innovation. With four campuses in Australia and a presence in Malaysia, China, India, Indonesia and Italy, it is one of the most internationalised Australian universities. As a leading international medical research university with the largest medical faculty in Australia and integration with leading Australian teaching hospitals, we consistently rank in the top 50 universities worldwide for clinical, pre-clinical and health sciences.
For more news, visit Medicine, Nursing and Health Sciences or Monash University.
MEDIA ENQUIRIES