The impact of temperature variations on the frequency of heart attacks has long been recognized by scientists. However, the majority of the studies conducted to date have been in temperate climates with a wide variety of temperatures.
A group of scientists has now looked into how Singapore’s tropical climate’s restricted temperature ranges affect the frequency of a particular kind of myocardial infarction, which is the medical name for a heart attack. The findings, which were published in the journal Science of the Total Environment, may have implications for health policy for residents of tropical cosmopolitan cities.
According to co-senior author Professor Marcus Ong, Director of the Health Services & Systems Research Programme and the Pre-hospital & Emergency Research Centre (PERC) at Duke-NUS Medical School, “Using 10 years of nationally collected data, we found strong evidence that a drop of 1°C in ambient temperature increased the risk of a type of acute myocardial infarction in the population by 12%.”
Prof. Ong, who is also Senior Consultant at the Department of Emergency Medicine at Singapore General Hospital, continued, “Further, people aged 65 and beyond looked to be roughly 20% more vulnerable to colder temperatures compared to younger people” (SGH).
The Singapore Myocardial Infarction Registry’s daily patient data was examined as part of the investigation, which was carried out in partnership with Singapore’s National Environment Agency (NEA). The study team carefully sought out individuals who had non-ST-segment elevation myocardial infarction (NSTEMI). A blood vessel supplying the heart might get partially blocked, resulting in this type of acute heart attack. The electrocardiogram (ECG) results of the patient do not reveal the readily recognizable ST elevation that would indicate STEMI, a different form of heart attack that happens when the coronary artery is totally blocked. Since the 1980s, NSTEMI has become more common, whereas STEMI has been less common.
Between 2009 and 2018, the researchers were able to compile 60,643 reports of NSTEMI. They next conducted a statistical analysis to see how the beginning of NSTEMI in these patients was connected to regional meteorological information, including mean temperature and rainfall, that was gathered from weather stations located throughout Singapore.
For up to 10 days following a temperature drop, cooler ambient temperatures were independently linked to a higher risk of NSTEMI. Regarding the effects of warmer or colder temperatures on the risk of NSTEMI, there were no gender differences. Changes in rainfall were also not linked to a higher risk.
One of the study’s first authors, Dr. Andrew Ho, an Assistant Professor with PERC and an Associate Consultant with SGH’s Department of Emergency Medicine, stated that the study’s findings showed that cooler ambient temperatures raised the risk of heart attacks even in a region of the world that is generally considered to be warm. “This advances our understanding of how physical stress might result from temperature changes outside one’s normal range. We discovered some evidence that the elderly were more susceptible to environmental stressors, such as air pollution, in cooler temperatures. This finding is consistent with our earlier research, which demonstrated that the elderly were more susceptible to environmental stressors, such as air pollution. ”
Dr. Joel Aik, an environmental epidemiologist and co-senior author of the study from NEA who is also an Adjunct Assistant Professor with PERC, stated that although there are a number of individual-level risk factors for cardiovascular disease, none are as frequently experienced as weather patterns. “With special consequences for Singapore’s aging population, daily weather changes have the potential to cause cardiovascular disease events in at-risk people. These findings identify a risk factor that poses a serious public health risk in the context of climate change. ”
To corroborate the findings, longer-term research is required. The team also wants more research into the basic reasons why older people are more likely to get NSTEMI because of tropical cold.
