🟢 Strong Evidence
Microplastics have moved from theoretical concern to measurable clinical risk. A landmark study published in the New England Journal of Medicine found polyethylene in arterial plaques of nearly 6 in 10 cardiovascular patients undergoing carotid surgery, with those carrying detectable microplastics facing a nearly 4.5-fold increased risk of heart attack, stroke, or death during follow-up.
Key takeaways
- Polyethylene detected in 58.4% of atherosclerotic plaques analysed from 257 patients in a New Studies cohort, at mean concentrations of 21.7 µg per milligram of tissue
- Patients with detectable microplastics in plaque had hazard ratio of 4.53 (95% CI 2.00–10.27) for composite outcome of myocardial infarction, stroke, or death
- Prior research from Environment International (2022) confirmed plastic particles measurable in human blood at 1.6 µg per millilitre
- Finding shifts microplastics from epidemiological hypothesis to documented cardiovascular pathology
Study at a Glance
| Source | New England Journal of Medicine |
| Study type | Prospective cohort analysis with tissue characterisation |
| Sample size | N = 304 enrolled; 257 completed 33.7-month mean follow-up |
| Population | Patients undergoing carotid endarterectomy for asymptomatic carotid artery disease |
| Country | Italy |
Microplastic Prevalence and Cardiovascular Risk
Percentage of patients with detectable polymers in arterial plaques and associated mortality hazard ratios
Source: Marfella et al., New England Journal of Medicine, 2024 | Georgian Medical Journal News
Microplastics in plaques: from blood to arterial wall
The evidence chain now spans measurement across biological compartments. In 2022, researchers at the Environment International journal using double-shot pyrolysis gas chromatography-mass spectrometry documented plastic particles in whole blood from 22 healthy donors, with mean concentrations of 1.6 µg per millilitre for particles ≥700 nm in diameter. This represented what those authors termed “the first demonstration that plastic particles are bioavailable for systemic uptake into the human bloodstream.”
Building on this evidence, researchers led by Dr. Raffaele Marfella at the University of Campania Luigi Vanvitelli published their landmark analysis in the New England Journal of Medicine in 2024, examining 304 consecutive patients undergoing carotid endarterectomy for asymptomatic carotid artery disease. Excised plaque specimens were analysed using pyrolysis-gas chromatography-mass spectrometry, stable isotope analysis, and electron microscopy.
Clinical findings: prevalence, concentration, and prognosis
Of 257 patients who completed a mean 33.7-month follow-up, polyethylene was detected in plaques from 150 patients (58.4%), at a mean concentration of 21.7 µg per milligram of plaque tissue, according to Marfella and colleagues in NEJM. An additional 31 patients (12.1%) had measurable polyvinyl chloride. Electron microscopy visualised jagged-edged foreign particles inside plaque macrophages, confirming the presence of microplastics within inflammatory cells.
The clinical significance emerged in the outcomes analysis. Patients with detectable microplastics in their plaque had a hazard ratio of 4.53 (95% confidence interval 2.00 to 10.27, p
Polyethylene was detected in atherosclerotic plaques from 58.4% of patients undergoing carotid endarterectomy, and the presence of microplastics was associated with a 4.53-fold increased hazard ratio for myocardial infarction, stroke, or death compared to those without detectable microplastics.
— Dr. Raffaele Marfella, University of Campania Luigi Vanvitelli (New England Journal of Medicine, 2024)
Mechanisms and mechanistic gaps
How microplastics transit from ambient air or ingestion to arterial plaques remains incompletely characterised. Prior work by researchers including those at the Proceedings of the National Academy of Sciences (PNAS) in 2024 has begun to map exposure sources and bioavailability, though the complete exposure-to-plaque pathway requires further investigation. The observation of microplastics within macrophages in plaques suggests that once systemically uptaken, these particles trigger or amplify inflammatory responses characteristic of atherosclerosis.
The clinical implications are substantial. For cardiovascular specialists and primary care practitioners, these findings suggest that microplastic exposure may represent a modifiable or at least measurable risk factor in patients with established atherosclerotic disease. Whether future interventions targeting microplastic reduction or removal will improve outcomes remains untested.
What this means
Frequently asked questions
How do microplastics enter the human body?
Microplastics can be ingested through contaminated drinking water, food (particularly seafood and sea salt), and inhaled from air pollution and degraded synthetic textiles. Once absorbed systemically, they may deposit in tissues including the cardiovascular system, as demonstrated by Leslie and colleagues in Environment International.
Are microplastics present in everyone’s blood and arteries?
The 2022 Environment International study detected microplastics in blood from all 22 healthy donors tested, suggesting widespread exposure. However, the 2024 NEJM analysis found microplastics in plaques from 58.4% of cardiovascular patients—meaning significant variation exists in tissue deposition, possibly reflecting differences in exposure, genetics, or clearance mechanisms.
Can microplastics be removed from the body?
Current evidence does not support established removal strategies. Microplastics, particularly those embedded within macrophages in arterial plaques, appear resistant to physiological clearance. Research into targeted removal approaches is nascent, and no clinical interventions are yet proven effective, making prevention through exposure reduction the primary strategy.
The 2024 microplastics findings represent a watershed moment in environmental health, elevating what was long treated as a nascent concern into a documented pathological process linked to acute cardiovascular outcomes. As regulatory bodies and healthcare systems begin to integrate this evidence, the focus will shift from measurement to prevention—and ultimately to population-level interventions aimed at reducing plastic production and exposure.
Source: Microplastics in human tissue stopped being a theoretical concern in 2024
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Medically reviewed by Prof. Giorgi Pkhakadze, MD, MPH, PhD. Spotted an error? Contact the editorial team.
