Pollution leaves a mark on health: study finds more microplastics in heart attack patients

The blood flowing through the arteries carries oxygen, nutrients and a great deal of information about our lifestyle. There, in the current that runs through those vessels and supplies the heart, lies data about our degree of physical activity, our diet and, according to a recent article, the pollution we are exposed to. A study published Wednesday in the journal European Heart Journal detected more microplastics in the blood of heart attack patients than in people who are healthy or who have chronic ischemic heart disease. Smokers and people more exposed to air pollution also showed a higher presence of these microscopic materials.

The authors say their findings bolster the growing body of evidence that environmental pollution can affect cardiovascular health. “These findings do not prove that microplastics cause heart attacks, but they reveal a strong association between environmental exposure, the presence of microplastics in the blood and cardiovascular disease. In our study, a history of smoking was associated with the presence of microplastics in the blood. Our findings suggest that smoking could facilitate the entry of microplastics and nanoplastics into the bloodstream via the lungs. Air pollution could act in a similar way,” summarizes Emanuele Barbato, director of the Cardiology Unit at Sant’Andrea University Hospital in Rome and an author of the study, in a statement. Other experts caution, however, that measuring the presence and the real effect of microplastics on health remains a technical challenge and call for more studies and finer detection techniques before drawing firm conclusions.

The planet is infested with plastics. And when these break down into ever smaller fragments — microplastics are pieces smaller than five millimeters — they can spread unchecked everywhere, including throughout the human body. They have been found inside the liver, kidney, intestine and human brain, among other tissues. Concern is growing about the impact these tiny particles may have on health.

Evidence on the effect of microplastics on cardiovascular health is limited. The same authors of this study, in another investigation published in 2024, found micro- and nanoplastics in atheroma plaques (fatty deposits that adhere to artery walls) and linked the presence of these contaminants to a higher risk of heart attack and stroke. But the burden of microplastics in the blood of people with coronary syndrome (a group of conditions characterized by an interruption in blood flow to the heart) remained, until now, unknown, the authors explain.

In this new study, scientists recruited 61 patients: some were diagnosed with myocardial infarction, others with chronic ischemic heart disease and others had normal coronary arteries. “We chose these three groups because they are representative of the full spectrum of coronary disease in everyday life: from normal coronary circulation, through long-standing stable disease, to an acute cardiovascular event,” Emanuele Barbato and Pasquale Paolisso said in a response to EL PAÍS.

After analyzing the blood, they found that 84% of patients with heart attacks had microplastics. The frequency fell to 40% in people with chronic disease and was only 32% in people with normal coronary arteries. “The finding that the plastic burden was much higher in patients with heart attacks led us to consider a possible relationship with plaque [atheroma] instability and acute events, rather than with stable disease alone,” they say.

Smoking, a predictor

The authors also found that smoking predicted the presence of microplastics: particles were found in all smokers with heart attacks, while none were found in any of the healthy non-smoking participants. The same pattern held for exposure to air pollutants such as fine particulate matter (PM2.5). “Both exposures appeared to amplify each other: all patients who smoked and lived in areas with high air pollution had detectable plastics, compared with only one in eight of those who neither smoked nor were highly exposed.”

The authors hypothesize a biological rationale for this link: “Both cigarette smoke and polluted air can carry microplastics or facilitate their inhalation and transfer from the lungs into the bloodstream. Our interpretation is that smoking and air pollution act, in effect, as vectors — carriers and facilitators — of microplastics.” They offer a “cautious” reflection: “We do not claim that microplastics are the reason smoking and air pollution harm the heart, but they appear to be associated with them.”

The authors acknowledge that the number of patients in this study is limited and the results cannot be understood as definitive or established facts, but rather as hypothesis-generating. “The results support the idea that environmental contaminants — and potentially microplastics — belong to the same group as traditional risk factors such as cholesterol, blood pressure, diabetes and smoking, within the broader concept of the environmental exposome,” they emphasize.

Until now, they note, available evidence on the link between microplastics and cardiovascular disease was limited to laboratory and animal experiments. Their study, they say, broadens the picture because “it is one of the first to detect and measure these particles directly in ‘live’ coronary blood — the blood that flows through the arteries that feed the heart — and to do so across the full spectrum of coronary disease.” “This design allows us to show a clear gradient: the plastic burden increased in proportion to the severity of the clinical presentation.”

Another novelty, they add, is the relationship between the presence of these particles and specific environmental exposures, such as smoking or air pollution. “This reframes the issue of microplastics not as an isolated curiosity but as another link in a wider environmental exposome interconnected with the air we breathe and our habits, and reinforces the need to study and address these exposures jointly rather than in isolation,” they say.

A study with limitations

Ignacio Fernández Lozano, president of the Spanish Society of Cardiology, considers this research “highly relevant because it shows a strong relationship between microplastics and heart attack,” although he recalls: “Causality cannot be established.”

In remarks to the SMC portal, some experts are more cautious and point to the difficulty of measuring microplastics in human blood or identifying all pathways of exposure to these particles. Thava Palanisami, team leader of the Australian Research and Innovation in Plastics Laboratory at the University of Newcastle, welcomes the study’s contribution “to the evidence that plastic pollution is an emerging public health problem that deserves serious attention,” but raises another limitation: “[The study] did not distinguish whether the observed biological effects were caused by the particles themselves, by the chemicals they carry or by joint exposure to other environmental contaminants, such as air pollution and tobacco smoke.”

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