We often see scary headlines about our health in the news. "This food causes cancer!" or "That habit will ruin your life!" But how much of it is true? Good science is careful and full of questions. Sensational headlines often ignore the details.
Today, we're going to be scientific detectives 🕵️. We'll look at a real 2024 study about tiny plastics found in the human body and their possible link to heart problems. Our goal isn't to become experts in medicine, but to become experts in reading the news critically. We will learn how to separate a flashy headline from the scientific evidence.
Headlines are designed to grab your attention, but they don't always tell the whole story.
Key Vocabulary
Before we dive into the study, let's understand some key terms scientists use. This language helps them be precise and honest about what they know and don't know.
| Word | Definition | Example |
|---|---|---|
| cohort | a group of people who are studied over a period of time and have something in common (e.g., age, location, medical condition). | The study followed a cohort of 257 patients who were having surgery. |
| endpoint | the main outcome that a study is designed to measure. | The primary endpoint of the study was a major event like a heart attack, stroke, or death. |
| confounder | an unmeasured factor that could be the real cause of an outcome. For example, if people who eat more ice cream also get more sunburns, the confounder is sunny weather—not the ice cream. | Smoking is a potential confounder because it could increase heart attack risk independently of any other factor. |
| caveat | a warning or limitation; a detail to consider before making a conclusion. | A major caveat is that the study was small, so the results may not apply to everyone. |
| generalizability | the extent to which the findings of a study can be applied to a larger population. | The study's generalizability is limited because all the patients were from one region in Italy. |
Skim (10 mins)
First, let's understand the basics of the study. Read the simplified summary below. Don't worry about understanding every word. Focus on these three questions. Discuss your answers with a partner.
- Who were the patients in this study (the cohort)?
- What did the scientists measure in their bodies?
- What negative health event was the main endpoint?
Study Summary: Microplastics in Carotid Artery Plaque
A study published in the New England Journal of Medicine investigated if microplastics and nanoplastics (MNPs) could be found inside the fatty deposits (plaque) that clog arteries.
The cohort consisted of 257 patients in Italy who were having surgery (a carotid endarterectomy) to remove plaque from an artery in their neck. Scientists analyzed the removed plaque. They found that 150 patients (58.4%) had measurable amounts of MNPs in their plaque, most commonly polyethylene (from plastic bags) and PVC. They also found that tissue with plastics had more signs of inflammation.
After following the patients for about three years, the researchers found a significant link. Patients with MNPs in their plaque had a 4.5 times higher risk of the primary endpoint—a heart attack, stroke, or death from any cause—compared to patients whose plaque was plastic-free.
Source: Raffaele Marfella, M.D., Ph.D., et al. (2024, March 7). Microplastics and Nanoplastics in Atheromas and Cardiovascular Events. The New England Journal of Medicine. Retrieved from https://www.nejm.org/doi/full/10.1056/NEJMoa2309822
Limitations Lab (15 mins)
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