New study highlights possible link between tattoos and lymphoma, but experts say more research needed

CNN
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A Swedish study has discovered a potential link between tattoos and a type of cancer called malignant lymphoma, but it ultimately calls for more research on the subject, and Cancer experts say the possible link is exaggerated.

Lund University researchers said they wanted to carry out the study because very little is known about the long-term health effects of tattooing, despite its continued popularity. In the United States alone, nearly a third of people have at least one tattoo, according to a 2023 survey by the Pew Research Center.

The study, published in the most recent edition of the journal eClinicalMedicine, involved almost 12,000 people in Sweden. Using population registries, researchers identified all people diagnosed with malignant lymphoma between 2007 and 2017 – almost 3,000 people – and compared them to a group of the same age and gender who did not have of cancer.

Malignant lymphoma is a cancer of the lymphatic system, the part of the body that helps fight germs and disease. Known risk factors include a weakened immune system caused by illness or immune disorders like AIDS, infections like Epstein-Barr, age, and a family history of the disease. Some exposure to chemicals like pesticides and herbicides can also increase the risk of lymphoma, in addition to second-hand smoke.

In 2021, the study authors sent questionnaires to people they had identified, asking them about certain lifestyle factors that could increase the risk of this type of cancer and whether they had tattoos.

Even after researchers took into account factors known to affect cancer risk, such as smoking and age, they found that the risk of malignant lymphoma was 21% higher among those who had at least one tattoo. The discovery is only an association, not a direct link, but The study authors emphasized that additional research will be needed to flesh out this conclusion.

To the researchers’ surprise, they found no evidence to suggest that the risk increased as the person’s skin was covered with more tattoos.

“We don’t yet know why this is the case. One can only assume that a tattoo, regardless of its size, triggers mild inflammation in the body, which in turn can trigger cancer,” said co-author Christel Nielsen, associate professor in the Division of Medicine work and the environment. at Lund University, in a press release. “So the picture is more complex than we initially thought. »

The study wasn’t designed to determine what, if any, link might be between cancer and tattoos, but experts are skeptical.

The conclusion is “really overblown,” said Dr. Timothy Rebbeck, an epidemiologist at the Dana-Farber Cancer Institute and professor at the Harvard TH Chan School of Public Health, who was not involved in the research.

“If I had written this article, if I were the editor, I would have said the conclusion is that there is no evidence of a strong association,” he said.

The data is strong, he says, but the main risk factors for lymphomas are not found in tattooing.

“I would say the message here should be: We haven’t really learned much about whether tattoos are associated with cancer, and if I had to draw a conclusion, I would say that the data suggest there is no association,” Rebbeck said, noting that a smaller A 2023 study on the link between tattooing and lymphomas or hematologic cancer also found no increased risk.

The 21% estimate of additional risk comes from the new study’s models, but it is not statistically significant, he said.

Dr. Catherine Diefenbach, director of the lymphoma clinical program at NYU Langone Health Perlmutter Cancer Center, said some things in the study don’t add up.

“What doesn’t make sense to me is why there is no correlation with tattoo size. It doesn’t really make sense to me that if there is an immune or toxic response, the larger tattoo has no impact on the association,” she said. “This study raises a lot of questions for me. »

Diefenbach said she had never been asked about the link between tattooing and cancer, but had seen news reports about the new research.

“I think people get very nervous about something that is a first study that needs to be validated,” she said.

The study authors believe that if tattoos increase the risk of malignant lymphoma, it could be due in part to a problem with the ink itself. Tattoo ink can often contain chemicals considered carcinogenic, including metals and polycyclic aromatic hydrocarbons.

Previous studies have shown that ink can sometimes travel through the body and tiny particles can get stuck in lymph nodes, which can lead to health problems.

Another study found that tattoo ink may slightly alter parts of blood cells that communicate with others, but it’s unclear whether this has any effect on health.

Even infections are rare after a tattoo, studies show. In 2023, the United States Food and Drug Administration released draft guidelines for tattoo ink manufacturers and their distributors to help them recognize when ink may be contaminated, after the The agency has received reports of contaminated inks and that some companies have recalled these inks. The FDA will register and investigate complaints against the industry, but it does not regulate the practice or the inks used in tattooing because it is considered a cosmetic procedure.

Nielsen said his group will examine whether tattoos are associated with other types of cancer or inflammatory diseases such as arthritis, lupus, high blood pressure and heart disease.

Rebbeck notes that these types of research can be difficult for the public to interpret. He helps run cancerfactfinder.org, which aims to help people understand what does and doesn’t cause cancer. Some have asked about tattoos, but the research doesn’t really show a connection, he says.

“I would say we don’t know much, but there’s no solid evidence that a tattoo is going to cause cancer,” Rebbeck said.