- Microplastics were found in the blood vessel plaque of half of the participants in a study.
- People with microplastics in their plaque were more likely to have a heart attack or stroke.
People who had microplastics in their blood vessels in a study were more likely to have a heart attack, stroke, or die earlier than those who didn't.
This is the first time a possible link between microplastics and these conditions — as well as human disease in general — has been made, following decades of speculation surrounding their potential health impact.
Micro and nanoplastics are tiny particles that shed from plastic. They are so small that they can enter human cells and have been found everywhere from the summit of Mount Everest to inside human lungs. Scientists fear that broken-down plastic could cause inflammation and other health issues in the body, but there has been limited evidence to suggest this until now.
Microplastics can be between five millimeters and one micrometer long. A micrometer is one-millionth of a meter, and a human hair is about 70 micrometers across. Nanoplastics are particles smaller than one micrometer. They are measured in nanometers or billionths of a meter.
The authors of the study, published March 6 in the New England Journal of Medicine, decided to embark on the research because they suspected plastic pollution might be behind in a rise in cardiovascular events they were seeing in patients who would normally be considered low-risk.
Researchers in Naples, Italy, examined the fatty cholesterol deposits, also called plaque, of 257 patients who had undergone surgery to remove a build-up from the arteries that carry blood to the brain. They were surprised to find micro or nanoplastics in more than 50% of the samples, Raffaele Marfella, first author of the study and cardiology researcher at the University of Campania Luigi Vanvitelli, Marfella told Business Insider via email.
Over the following 34 months, the researchers monitored the participants and found that those with microplastics in their plaque sample were almost five times more likely to experience a nonfatal heart attack, stroke, or death from any cause, than those who had none.
Younger men were more likely to have microplastics in their plaque
It's important to note that the findings don't prove that microplastics cause heart attacks and strokes but rather suggest a link between the two. Other factors such as diet, lifestyle, and air pollution exposure could play a major role and were not looked at, the authors said.
Participants who showed evidence of microplastics in their plaque were typically younger, more likely to be men, to smoke, and to have diabetes, cardiovascular disease, and high cholesterol. They were less likely to have hypertension, the authors said.
Their plaque also contained biomarkers of inflammation, the study said. This might suggest that microplastics in the bloodstream exacerbate inflammation, which increases the risk of heart attacks and stroke, study author Francesco Prattichizzo told New Scientist.
"Unfortunately, human tissue plastic contamination is not unique but is very widespread. It is worrisome their likely effect on cardiovascular health," Marfella told BI.
However, he pointed out that although preventative measures were taken to make the lab conditions plastic-free, contamination during the research can't be firmly ruled out. Their findings also may not be representative of the general population, as they only looked at people undergoing surgery to remove plaque from the carotid arteries.
Dr. Vahitha Abdul Salam, a senior lecturer in vascular pharmacology at Queen Mary University of London who studies microplastics and human health, was not involved in the study. She told BI that while the findings don't directly link micro and nanoplastics to the cause of any diseases, they further validate that plastic particles get into our circulation and lodge in tissues.
In 2023, the global plastics market was valued at $712 billion, and it's projected to reach more than $1,050 billion by 2033, according to Statista. Experts, however, recommend cutting plastic use as much as possible. Abdul Salam advised avoiding single-use plastic containers and using natural-based materials.