- \n
- * <\/span>Intergovernmental Panel on Climate Change: An intergovernmental organization established by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) to coordinate the collection and assessment of scientific research concerning global warming by international expert communities.<\/li>\n<\/ul>\n
The risk of lifestyle-related diseases amid climate change was set out in the Working Group II contribution, which was published in February 2022. Reading this report, one can see that the health hazards expected to increase as a result of climate change include infectious diseases, heat stroke, psychiatric disorders, and lifestyle-related diseases; the category of lifestyle-related diseases includes cardiovascular disease, noninfectious respiratory diseases, cancer, and diabetes and other endocrine diseases (Figure 1).<\/p>\n
![\"\"](\"https:\/\/healthist.net\/en\/wp-content\/uploads\/sites\/3\/2025\/12\/294_en_feature01_02_fig01-1.jpg\")
Partially modified from Ishii, K. IPSJ Magazine, 63: e26–fe30, 2022.<\/small><\/p>\nFigure 1. <\/span>Lifestyle-related diseases of concern due to climate change<\/span><\/strong>Cardiovascular disease and kidney disease are closely related, and because they are both associated with glucose metabolism, it is not uncommon for multiple lifestyle-related diseases to coexist in a single patient.<\/p>\n<\/div>\n
Of these, I believe that the risks will be particularly elevated for cardiovascular disease and noninfectious respiratory diseases. Cardiovascular disease is a group of diseases affecting the heart and blood vessels, and includes conditions that can be fatal, such as myocardial infarction and stroke. In fact, cardiac disease is the second leading cause of death in Japan, with cerebrovascular disease in fourth place (Ministry of Health, Labour and Welfare (MHLW): 2024 Annual Report of Monthly Vital Statistics).<\/p>\n
In the case of cardiovascular disease, exposure to air pollutants such as fine particulate matter (PM2.5) and ozone is to damage blood vessels, promote inflammation and thrombosis, and induce hypertensive responses. PM2.5 tends to increase under high-humidity conditions, and ozone concentrations also rise with higher temperatures. Moreover, an increase in the number of forest fires due to climate change is anticipated, suggesting the possibility that smoke from such fires may further elevate the risk of cardiovascular disease.<\/p>\n
In addition to this, hot environments could increase the risk of cardiovascular disease as a result of reduced physical activity, sleep disturbances, and dehydration, among others. High blood pressure (hypertension) is a background factor in many cases of cardiovascular disease; blood pressure is heavily influenced by temperature. When the temperature is low, blood vessels contract, making increases in blood pressure more likely, while high temperatures cause blood vessels to dilate, leading to decreases in blood pressure. However, large fluctuations can trigger cardiac disease and cerebrovascular disease. These blood pressure fluctuations are called heat shock; the risk posed by the temperature difference between the bathroom and the changing area in Japanese homes in winter is already widely known, but even in summer, the difference between extremely high outdoor temperatures and air-conditioned indoor environments also poses a risk.<\/p>\n
Exposure to PM2.5, ozone, and other atmospheric pollutants is closely related to the onset and progression of noninfectious respiratory diseases, including chronic obstructive pulmonary disease (COPD), asthma, and lung cancer. In addition, hot environments can lead to declines in pulmonary function, worsening people’s clinical conditions. Also known as a lifestyle-related disease of the lungs or a smoker’s disease, COPD is a disease that causes chronic inflammation of the lungs due to long-term inhalation of hazardous substances, such as air pollution or cigarette smoke. Because climate change directly exacerbates these environmental exposures, it is thought to pose a particularly high risk.<\/p>\n
Then there is diabetes; as this condition impairs the function of sweat glands due to a disorder of the autonomic nervous system, the risk of suffering or dying from heat stroke and other heat-related diseases is thought to be high. In particular, it has been reported that rising temperatures further increase morbidity and mortality rates in diabetics with cardiovascular complications.<\/p>\n
Another disease affected by numerous environmental factors, cancer is the leading cause of death in Japanese people, as readers are doubtless aware (MHLW: 2024 Annual Report of Monthly Vital Statistics Reports). The IPCC report states that, although the degree of increase is unclear, there is a strong possibility that climate change will increase the risk of a number of cancers. It is feared that greater exposure to known carcinogens due to climate change will increase the risk of cancer; this includes, for example, skin cancers caused by changes in exposure to ultraviolet rays arising from shifts in precipitation patterns, as well as lung cancer caused by air pollution. There could well also be the potential for increases in the risk of cancers closely connected to living habits, such as pancreatic cancer, colon cancer, esophageal cancer, gastric cancer, and liver cancer.<\/p>\n
Multimorbidity increases risks<\/h2>\n
As described above, climate change affects a variety of lifestyle-related diseases, but the bigger problem is that diabetes is often accompanied by several other lifestyle-related diseases, including cardiovascular disease, cerebrovascular disease, and kidney disease. When the effects of climate change come into play, there is a possibility that a patient’s condition will worsen in a way in a chain-reaction-like manner.<\/p>\n
In addition, heat stroke, infectious diseases, and psychiatric disorders—all of which are strongly influenced by climate change—are correlated with lifestyle-related diseases. In the case of infectious diseases, the spread of infection can transform people’s ways of life, as we experienced with the COVID-19 pandemic. Restrictions on leaving the house led to a decline in physical activity, while anxiety and stress made people more prone to adopting unhealthy living habits, such as excessive eating, alcohol consumption, and smoking. Furthermore, it has been pointed out that people with lifestyle-related diseases are more susceptible to infectious diseases and more likely to experience their progression to severe forms. Various studies have also revealed that psychiatric disorders are interrelated with cardiovascular disease and diabetes.<\/p>\n
Of these, heat stroke—which often develops in hot and humid environments against a background of dehydration—is a condition in which the impact of climate change is clearly apparent. In Japan, the record-breaking heat of recent years has, combined with the aging of the population, driven up the incidence of heat stroke, with the number of people transported by ambulance due to this condition reaching an all-time high in 2024. In Europe, too, reports estimate that the number of heat stroke-related deaths during the 2024 heat wave exceeded 60,000.<\/p>\n
Accordingly, focusing on heat stroke, we used a supercomputer to analyze medical insurance claims data in order to investigate the connection between heat stroke and other diseases, including lifestyle-related diseases.<\/p>\n
Medical insurance claims data consist of statements of medical expenses issued by medical institutions under the public insurance system, and include detailed information such as the patient’s diagnoses, medical procedures received, and prescribed medications. In Japan, which has a universal public health insurance system, these claims data are increasingly being used—including in our research—as a form of big data for understanding the actual state of medical care.<\/p>\n
Focusing on patients receiving outpatient care for heat stroke between 2011 and 2019, we calculated the odds ratios for various diseases that co-occur with heat stroke. An odds ratio is an indicator of the likelihood of a phenomenon occurring in two groups; in this study, a higher odds ratio indicates that a heat-stroke patient is more likely to have a disease than a patient who does not have heat stroke (Figure 2).<\/p>\n
![\"\"](\"https:\/\/healthist.net\/en\/wp-content\/uploads\/sites\/3\/2025\/12\/294_en_feature01_02_fig02-1.png\")
Partially adapted from Nishio, T. et al. 21st Forum on Information Technology, Information Processing Society of Japan, 2022.<\/small><\/p>\nFigure 2. <\/span>Diseases comorbid with heat stroke (outpatients: 2011–2019)<\/span><\/strong>An odds ratio of 1.0 or higher indicates a greater tendency to comorbidity with heat stroke. For example, an odds ratio of 1.5 means more likely to have that disease compared with someone who does not experience heat stroke.<\/p>\n<\/div>\n
We obtained data suggesting a relationship between heat stroke and psychiatric disorders, with particularly high odds ratios for depressive episodes, sleep disorders, and Alzheimer’s disease. Among lifestyle-related diseases, ischemic heart disease, hypertension, hypertensive renal dysfunction, cerebrovascular disease, dyslipidemia, hepatic dysfunction, hyperuricemia, and diabetes all showed odds ratios indicating coexistence with heat stroke, suggesting that many of the patients were affected by these conditions. On the other hand, our results showed low odds ratios for cancer and schizophrenia. Taken together, these findings suggest that people with lifestyle diseases are prone to heat stroke.<\/p>\n
Another health problem that occurs when temperatures rise is sleep disorders. Most people have likely had the experience of being unable to sleep due to the heat. In a study in which we used medical insurance claims data to investigate diseases that co-occur with sleep disorders, in a similar way to the aforementioned study, we compared patients with sleep disorders against those without such disorders. The odds ratios for Parkinson’s disease and dementia were strikingly high, while among lifestyle-related diseases, ischemic heart disease, cerebrovascular accident, arterial occlusion, and hypertensive renal dysfunction were notable (Figure 3). As sleep disorders are a symptom of Parkinson’s disease, the link between sleep disorders and dementia has long been recognized. Lifestyle diseases are also known to be involved in the onset of dementia, suggesting that these conditions are mutually related.<\/p>\n
![\"\"](\"https:\/\/healthist.net\/en\/wp-content\/uploads\/sites\/3\/2025\/12\/294_en_feature01_02_fig03.png\")
<\/small><\/p>\nFigure 3. <\/span>Comorbid diseases in patients with sleep disorders (outpatients: 2011–2020)<\/span><\/strong>People with sleep disorders appear to be more prone to developing neurodegenerative diseases such as Parkinson’s disease or dementia, as well as lifestyle-related conditions including ischemic heart disease, cerebrovascular disease, arterial occlusion, and hypertensive renal dysfunction.<\/p>\n<\/div>\n
Based on the above, it is thought that people with lifestyle-related diseases are at risk of developing conditions that are expected to increase as a result of climate change, and that contracting such conditions may further exacerbate their existing lifestyle-related diseases.<\/p>\n
Climate change is the planet’s lifestyle-related disease<\/h2>\n
The fact is that most lifestyle-related diseases are already on the rise. In the case of cardiac disease in particular, the aging of the population and the increasing prevalence of lifestyle-related diseases have been accompanied by a pronounced increase in heart failure, which is the final form of the clinical condition. In 2025, Japan’s baby-boom generation reached 75 years old, which is the age range at which people are susceptible to heart failure; given this fact, it is expected that we will soon see a sudden and dramatic rise in heart failure—already being referred to as a “heart failure pandemic”—is expected in the near future.<\/p>\n
Scientists estimate that hypertension, which often coexists with cardiovascular disease, kidney disease, and diabetes, has a prevalence of around 40% among Japanese adults. It is anticipated that the rise in lifestyle-related diseases will accelerate as the impacts of climate change begin to come into play more substantially.<\/p>\n
If the number of patients increases, medical economics and health care systems will come under increasing pressure, with medical expenses rising further and medical institutions facing a mounting burden. In addition, because lifestyle-related diseases are chronic conditions, drug therapy and other forms of ongoing treatment are required. If extreme weather conditions lead to an increase in natural disasters, another conceivable risk is that people’s conditions could worsen if access to medical care is cut off, preventing them from receiving appropriate treatment.<\/p>\n
It is vital to promote both the optimization of medical expenditure and improved access to medical care during disasters, as these issues already pose significant challenges today. Accordingly, we are also undertaking studies in such areas as the evaluation of medical economics using health-care big data and the delivery of medications using drones.<\/p>\n
As described above, lifestyle-related diseases involve a variety of intertwined risk factors, and climate change is expected to amplify those risks across the board (Figure 4). However, climate change could above all be described as a lifestyle-related disease of the Earth, and we will not reach a radical solution unless we transform our social systems and ways of life, including curbing greenhouse gases. In parallel with such measures on a global scale, what we as individuals can do about our own health is to make steady efforts to adopt healthier daily habits.<\/p>\n
![\"\"](\"https:\/\/healthist.net\/en\/wp-content\/uploads\/sites\/3\/2025\/12\/294_en_feature01_02_fig04-1.png\")
<\/small><\/p>\nFigure 4. <\/span>Risk of lifestyle-related diseases due to climate change<\/span><\/strong>There are concerns that the health risks associated with climate change will increase the risk of lifestyle-related diseases, leading to a further rise in the number of affected individuals and exacerbating the severity of these conditions.<\/p>\n<\/div>\n
In fact, immediately after the publication of the aforementioned IPCC report, I gave a lecture about health hazards amid global warming, but at the time I felt that public interest in the subject was limited. That might have been because it was right in the middle of the pandemic, so people were not in a position to turn their attention to other problems. Today, as reports of damage from torrential rains and heat waves have become almost routine, the severity of the situation is increasingly apparent. Precisely because of the situation we are in now, I would like people to look at it as an opportunity to reflect on—and improve—their own lifestyle habits. <\/p>\n
As well as continuing to use health-care big data in our research, we plan to carry out more detailed analyses with the aid of quantum computing, in the hope that we can help prevent the onset and worsening of lifestyle-related diseases.<\/p>\n
(Figures courtesy of Kazuo Ishii)<\/small><\/div>\n","protected":false},"excerpt":{"rendered":"A variety of interconnected risk factors are involved in lifestyle-related diseases, and climate change further amplifies those risks. For example, people with diabetes mellitus (diabetes) are known to be more likely to develop several other lifestyle-related diseases, including cardiac disease, cerebrovascular disease, and kidney disease. When the impact of climate change is considered, these risk factors can intensify in a chain-reaction-like manner, accelerating the rise in lifestyle-related diseases. Additionally, reduced physical activity and sleep disturbances in extremely hot environments act as risk factors for cardiovascular disease and other conditions. We are now at a point where modifying our lifestyle has become essential.<\/p>\n","protected":false},"author":2,"featured_media":2587,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[17],"tags":[104],"class_list":["post-2569","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-society","tag-heat-illness"],"acf":{"author":"composition by Yumi Ohuchi
illustration by Rokuhisa Chino","intro":"A variety of interconnected risk factors are involved in lifestyle-related diseases, and climate change further amplifies those risks. For example, people with diabetes mellitus (diabetes) are known to be more likely to develop several other lifestyle-related diseases, including cardiac disease, cerebrovascular disease, and kidney disease. When the impact of climate change is considered, these risk factors can intensify in a chain-reaction-like manner, accelerating the rise in lifestyle-related diseases. Additionally, reduced physical activity and sleep disturbances in extremely hot environments act as risk factors for cardiovascular disease and other conditions. We are now at a point where modifying our lifestyle has become essential.<\/p>","person":[{"acf_fc_layout":"personcontent","personimg":2564,"personsholder":"Professor, Department of Applied Information Engineering, Faculty of Engineering, Suwa University of Science","personname":"Kazuo Ishii","persondetail":"He holds a Ph.D. in medicine and is a licensed pharmacist. After graduating from the Department of Pharmacy at Shizuoka College of Pharmacy in 1987, he successfully completed a master\u2019s program at the college\u2019s Graduate School of Pharmaceutical Science in 1989, followed by a doctoral program at the University of Tokushima in 1995. He then held posts at RIKEN and the Institute of Medical Science, the University of Tokyo, among others, before becoming a professor in the Faculty of Agriculture at Tokyo University of Agriculture and Technology in 2011. In 2017, he was appointed associate professor at Kurume University\u2019s Biostatistics Center, and took up his current post in 2021. His main research interest is applying big data analysis to address global social challenges, including global warming, declining birthrates, and population aging, thereby contributing to the SDGs."}],"issue":2566,"custom_css":""},"_links":{"self":[{"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/posts\/2569","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/comments?post=2569"}],"version-history":[{"count":0,"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/posts\/2569\/revisions"}],"acf:post":[{"embeddable":true,"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/issue\/2566"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/media\/2587"}],"wp:attachment":[{"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/media?parent=2569"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/categories?post=2569"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/healthist.net\/en\/wp-json\/wp\/v2\/tags?post=2569"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}