Researchers from Kumamoto University have reported that behavioral changes during the COVID-19 pandemic, particularly widespread mask-wearing, may have reduced the risk of certain heart attacks triggered by air pollution. The study was led by Dr. Masanobu Ishii and colleagues and published in the European Heart Journal.
Fine particulate matter, known as PM2.5, is recognized as a significant environmental risk factor for cardiovascular disease. These tiny airborne particles can penetrate deep into the lungs and trigger inflammation, oxidative stress, and blood vessel dysfunction. Such exposure can lead to acute myocardial infarction (AMI), commonly referred to as a heart attack.
The research team analyzed data from Japan's nationwide cardiovascular database (JROAD-DPC), reviewing records of 270,091 patients hospitalized for AMI between 2012 and 2022. They examined how short-term exposure to PM2.5 affected heart attack risk before and during the COVID-19 pandemic—a period marked by increased mask use and reduced mobility.
Results showed that short-term exposure to PM2.5 raised the risk of all types of AMI. However, one specific subtype—MINOCA (myocardial infarction with non-obstructive coronary arteries)—had a particularly strong link to air pollution. After the start of the pandemic, researchers observed a significant decline in PM2.5-related MINOCA cases, while rates of MI-CAD (heart attacks with coronary artery obstruction) remained largely unchanged.
According to the researchers, "pandemic-related preventive behaviors—especially mask-wearing—may have reduced individual exposure to harmful particulate matter, thereby lowering the risk of pollution-triggered vascular dysfunction such as coronary spasm or microvascular impairment."
The study provides evidence that simple protective measures can help reduce cardiovascular risks associated with environmental exposures. In Japan, where strict lockdowns were not imposed during the pandemic, voluntary public health practices appear to have had measurable benefits for heart health.
The authors note that improving air quality should remain a long-term goal but highlight that accessible interventions like mask use during periods of high pollution could help protect vulnerable groups.
"These insights may help shape future preventive cardiology and public health strategies worldwide," according to the research team.
