Plastics are now everywhere, with tiny fragments found in several major organs of the human body, including the placenta.

Given how easily the microscopic particles infiltrate our tissues, it’s vital that we learn exactly what kinds of risks they could pose to our health.

Researchers have been busy studying the effects of microplastics in mini-replicas of organs, and in mice, to get a sense of how they might impact the human body. However, the concentrations of microplastics used in those studies might not reflect people’s real-world exposure, and few studies have been done in humans.

Now, a small study in Italy has found shards of microplastics in fatty deposits surgically removed from patients who had an operation to open up their clogged arteries – and reported their health outcomes nearly 3 years later.

Removing fatty plaques from narrowed arteries in a procedure called a carotid endarterectomy reduces the risk of future strokes.

The team behind this new study, led by Raffaele Marfella, a medical researcher at the University of Campania in Naples, wondered how the risk of stroke – as well as heart attacks and death – compared between patients who had microplastics in their plaques and those who did not.

Following 257 patients for 34 months, the researchers found nearly 60 percent of them had measurable amounts of polyethylene in plaques pulled from their fat-thickened arteries, and 12 percent also had polyvinyl chloride (PVC) in extracted fat deposits.

PVC comes in both rigid and flexible forms, and is used to make water pipes, plastic bottles, flooring, and packaging. Polyethylene is the most commonly produced plastic, used for plastic bags, films, and bottles, too.