Doctors and scientists are concerned about the impact of plastics, not only on the environment but on human health – and new research has found a potential link between microplastics and heart attacks and strokes. 

When plastics enter the environment, humans may inhale or ingest them. Moreover, just as plastics can take centuries to break down on earth, plastics do not easily break down within our bodies, potentially leading to accumulation over time.

Multiple studies have already detected microplastics in various organs, from the lungs to the placenta.

The newest study, published in the New England Journal of Medicine last month, involved more than 250 people who had carotid artery disease and were having surgery to remove the build-up of plaque from their carotid arteries, the main arteries that supply the brain with blood, located in the neck. 

More than half (58%) of these patients had microplastics or even smaller nanoplastics in a main artery, and those who did were 4.5 times more likely to experience a heart attack, a stroke or death in the approximately 34 months after the surgery than were those whose arteries were plastic-free.

The researchers collected plaque samples from 257 patients during their surgeries and performed a chemical analysis on them. They found that 150 had microplastics and nanoplastics in their arterial plaque, mainly polyethylene (in all 150 people) and polyvinyl chloride (in 31). 

These are two of the most commonly used plastics in the world; the researchers looked for 11 plastics.  

Polyethylene is usually used for packaging, such as plastic bags or containers. Polyvinyl chloride is a more versatile plastic used for anything from medical devices to window frames and flooring.

In addition to the increased risk of heart attack or stroke, the researchers also found that those with microplastics in their plaque samples had higher levels of biomarkers for inflammation.

However, the researchers pointed out that individuals with microplastics in their plaque also exhibited other risk factors such as smoking, high cholesterol, diabetes, and heart and circulatory diseases, all of which elevate the risk of heart attack and stroke to begin with. 

Moreover, since all of the study participants were already undergoing carotid artery surgery and were known to have carotid artery disease, it is too early to tell whether the results of this study can be generalized to a broader population. 

In addition, the researchers stressed that the study does not prove that microplastics cause heart attack or stroke, only that there is a potential relationship. 

Dr Steve Nissen, a heart expert at the Cleveland Clinic, told The Independent that while “the study is intriguing,” it has “substantial limitations.” 

He said, “It’s a wake-up call that perhaps we need to take the problem of microplastics more seriously. As a cause for heart disease? Not proven. As a potential cause? Yes, maybe.”

Cardiac function 

This is not the first study to examine the link between plastics and human health. A similar, separate study published earlier this year in Environment International also examined the effect of microplastics and nanoplastics on the cardiovascular system, finding that these plastics “affected cardiac functions and caused toxicity on (micro)vascular sites.”

Effects included abnormal heart rate, cardiac function impairment, pericardial edema, and myocardial fibrosis, as well as hemolysis, thrombosis, blood coagulation, and vascular endothelial damage. 

This latest study comes as global representatives, led by the United Nations Environment Programme (UNEP), are working to finalize a plastics treaty to help eliminate plastic pollution by the end of the year.

The fourth session of the Intergovernmental Negotiating Committee to develop an international legally binding instrument on plastic pollution, including in the marine environment (INC-4), is scheduled to take place from 23- 29 April in Ottawa, Canada

Image Credits: University of Oregon.