New study links chemical in plastics to fatal heart disease

A common ingredient of many plastics has just been linked to a high risk of death from diseases of the heart and blood vessels.

The chemical is known as DEHP. That’s short for di(2-ethylhexyl) phthalate. It’s a member of a family of chemicals used widely in our daily lives. Indeed, all of us carry trace levels of DEHP and other phthalates (THAA-laytz) in our bodies.

These chemicals are often added to plastics to make them softer and more flexible. DEHP, a very common member of this family, shows up in a huge range of everyday products, such as shower curtains, raincoats, toys, car upholstery and shoes. It’s also in food packaging and medical supplies (including blood bags).

See the broad range of products that contain DEHP and the many health effects that have been linked to this phthalate.

Leonardo Trasande and his team at New York University’s medical school in New York City probed for a possible link between DEHP and cardiovascular disease (CVD). The leading cause of death worldwide, CVD includes all diseases of the heart and blood vessels. Among them: clogged arteries (a source of heart attacks), stroke, heart failure and more.

To start, the NYU team gathered estimates on DEHP exposures across the globe. These data came from 216 studies published between 2000 and 2023. The studies measured, in people’s bodies, amounts of chemicals made when DEHP breaks down. Called metabolites, such chemicals indicate how much DEHP people were exposed to.

Next, the team looked at how CVD deaths and DEHP exposures had changed over the years. They compared DEHP data from 2008 with death rates from CVD 10 years later among people 55 to 64 years old. From this, they calculated what share of those deaths globally seemed to trace to this phthalate.

More than 2.6 million CVD deaths were recorded for this age group in 2018. The new study links 13.5 percent of them to this plasticizer.

Scientists Say: Correlation and Causation

The new data do not prove DEHP caused all of these deaths. The NYU team only found a link between the two. That’s a correlation — not proof yet that it caused these deaths. However, if the link is shown to be causal, that would be quite troubling: It would come to more than one in every eight CVD deaths worldwide.

Another caution: People encounter a mix of phthalates daily. In the new study, however, “our model was not able to take this into account,” says Sara Hyman of the NYU team. The group’s analysis also didn’t account for other factors that might play a role in heart disease, such as diet, exercise or other medical conditions. “More research is needed,” she says, to also account for these.

The NYU group shared its findings in the July issue of eBioMedicine.

One place where it’s hard to avoid DEHP: hospitals. IV bags, tubing and surgical gloves, for instance, all contain this plasticizer to keep these essential products flexible. gorodenkoff/iStock/Getty Images Plus

Rate varies by region

Changcheng Zhou is a biomedical scientist at the University of California, Riverside, who studies what causes cardiovascular disease. And he finds the death rate being linked to DEHP “quite alarming.”

That rate varied greatly across the globe. About three in every four of those deaths linked to DEHP occurred in the Middle East, South Asia, East Asia and the Pacific. That might be due to the large and growing plastics industries in those parts of the world, the NYU team suggests.

Future studies could refine these estimates further, the scientists say. Some national health surveys collect data on phthalate exposures. This is true in the United States, Canada and many nations in Europe. Elsewhere, such as in Latin America, Africa and Asia, such national monitoring is lacking, Hyman says. So her team’s estimates of DEHP exposure in those places are based on far fewer people. As such, she notes, links to DEHP in these places might be slightly less precise.

Different phthalates may affect different processes in the body. And they might not operate alone. “You do need to study the effect of the mixture” of phthalates people encounter regularly, says Mahua Choudhury. She studies environmental risks to our genes at Texas A&M University in College Station. Some phthalates, she notes, could lessen — or worsen — the health effects of others.

Studies linking DEHP to IQ and other problems in infants and children led to a 2008 U.S. ban on this phthalate in products aimed at young children. However, babies and other kids can still be exposed from foods and other sources of DEHP in the environment. Djavan Rodriguez/Moment/Getty Images Plus

Even kids can be affected by phthalates

Phthalates can enter the body when you eat food that had been sold, stored or heated in plastic. We also breathe them in from the air and absorb them through the skin. Once inside the body, they can tinker with hormone action. Previous research has also linked phthalates to diabetes, obesity, pregnancy complications — and yes, heart disease.

Also quite troubling: One 2020 study linked pregnant moms’ DEHP exposure with mental risks in their children — such as a lower IQ. Another study linked school-age kids’ exposures to DEHP with a lower IQ — especially in boys. A more limited IQ risk emerged for dibutyl phthalate (DBP). It’s another plasticizer and solvent. It’s used widely in making PVC plastic, inks, adhesives and cosmetics.

Prenatal exposure to DEHP and DBP also has been linked with lowering a boy’s preference for certain types of play, such as playing with toy guns. It also made boys more likely to engage in gender-neutral types of play — think puzzles or sports. No such change was seen in girls.

The new NYU study’s findings offer yet another reason to reduce our use of plastics, researchers say. “We’re going to become the plastic planet,” Zhou worries. “We need to start to really address this serious issue.”