Lab tests on the extracted plaques revealed polyethylene in 150 patients and polyvinyl chloride in 31, alongside signs of inflammation. On examination under an electron microscope, the researchers spotted jagged foreign particles in the fatty deposits, most less than a thousandth of a millimetre across.
The doctors followed 257 of the patients for an average of 34 months after they had carotid plaques removed. Those who had plastic particles in their plaques were 4.5 times more likely to have a stroke or heart attack, or to die from any cause, than those whose plaques were free from plastic pollution.
Marfella said the discovery of plastics in the plaques was “surprising” and that the likely effect on cardiovascular health was “worrisome”. The findings may explain what doctors call “residual cardiovascular risk”, he said, where 20%-30% of patients who have been treated for common risk factors, such as high blood pressure and diabetes, still go on to have heart attacks and strokes.
Further work is needed to confirm whether plastic pollution plays a role in strokes and heart attacks, but Marfella called for greater awareness of the potential threat.
“People must become aware of the risks we are taking with our lifestyle,” he said. “I hope the alarm message from our study will raise the consciousness of citizens, especially governments, to finally become aware of the importance of the health of our planet. To put it in a slogan that can unite the need for health for humans and the planet, plastic-free is healthy for the heart and the Earth.”
Holly Shiels, professor of integrative physiology at the University of Manchester, said the impact of micro- and nanoplastics on plaque formation and coronary heart disease needed greater attention. “It is conceivable that microplastics and nanoplastics, and the toxins they carry, could trigger events leading to the development of atherosclerosis,” she said.
