Study points to possible link between tattoos and lymphoma; experts ask for more data

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

The researchers, from Lund University, said they wanted to carry out the study because very little is known about the long-term health effects of tattoos, despite their growing popularity. In the United States, for example, nearly a third of people have at least one tattoo, according to a 2023 Pew Research Center survey.

The study, published in the most recent edition of eClinicalMedicine magazine, involved almost 12 thousand people in Sweden. Using population records, researchers identified all people diagnosed with malignant lymphoma between 2007 and 2017 – almost 3,000 people – and compared them with a group of the same age and gender who did not have 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 from diseases or immune disorders such as AIDS, infections such as Epstein-Barr, age and a family history of the disease. Some exposures to chemicals such as pesticides and herbicides can also increase the risk of lymphoma, in addition to secondhand smoke (secondhand smoke).

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

Even after researchers considered factors that are 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 just an association, not a direct link, but The study authors emphasized that more research will be needed to develop this conclusion .

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

“We still don’t know why this happened. We can only speculate that a tattoo, regardless of size, triggers low-grade inflammation in the body, which in turn can trigger cancer,” said co-author Christel Nielsen, associate professor in the University's Division of Occupational and Environmental Medicine. of Lund, in a press release. “The picture is therefore more complex than we initially thought.”

The study was not set up to determine what, if any, the link between cancer and tattoos might be, but experts are skeptical.

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

“If I were writing that paper, 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 solid, he said, but the main risk factors for lymphomas are not found in tattoos.

“I would say the message here should be that we really haven't learned much about whether tattoos are associated with cancer from this study, and if I had to come to a conclusion, I would say that the data suggests there is no association,” Rebbeck said, noting that a 2023 smaller study on the connection between tattoos and lymphomas or hematological cancer also found no increased risk.

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

Catherine Diefenbach, director of the Lymphoma Clinical Program at the Perlmutter Cancer Center at NYU Langone Health, a New York medical center, said some things about the study don't make sense.

“What doesn't make sense to me is why there is no correlation with the size of the tattoo. It doesn't make a lot of sense to me that if there's an immunological or toxic response that the larger tattoo wouldn't have any impact on the association,” she said. “I have a lot of questions about this study.”

Diefenbach said she has never been asked about a connection between tattoos and cancer, but has seen news reports about the new research.

“I think people are getting very nervous about something that is an early study and needs to be validated,” she said.

The study authors speculate that if tattoos increase the risk of malignant lymphoma, one reason may be a problem with the ink itself. Tattoo ink can often contain chemicals considered carcinogens, including metals and polycyclic aromatic hydrocarbons.

Previous studies showed that ink can sometimes travel through the body, and small particles can get trapped in lymph nodes, which could lead to health problems.

Another study found that tattoo ink could slightly alter parts of blood cells that communicate with others, but it's unclear whether this has any health effects.

Same infections are rare after tattooing, studies show. In 2023, the U.S. Food and Drug Administration issued preliminary guidelines to tattoo ink manufacturers and their distributors to help them recognize when ink may be contaminated, after the agency received reports of contaminated ink and some companies recalled such ink. The FDA will file and investigate complaints against the industry, but does not regulate the practice or the inks used in tattoos because they are considered a cosmetic procedure.

Nielsen said his group will investigate 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 this type of research can be difficult for the public to interpret. It helps manage the website cancerfactfinder.org, which aims to help people understand what causes cancer and what doesn't. Some people have asked about tattoos, but research doesn't really show a connection, he says.

“I would say we really don't know much, but there is no strong evidence that having a tattoo will cause cancer,” Rebbeck said.