A Swedish study from Lund University suggests a possible link between tattoos and a type of cancer called malignant lymphoma, but more research is needed. The study, published in eClinicalMedicine, looked at nearly 12,000 people in Sweden, including almost 3,000 with malignant lymphoma diagnosed between 2007 and 2017. These were compared to a similar group without cancer.
Malignant lymphoma affects the lymphatic system, which helps fight disease. Known risk factors include a weakened immune system, certain infections, age, family history, and exposure to chemicals like pesticides and secondhand smoke.
In 2021, the researchers sent questionnaires asking about lifestyle factors and tattoos. They found a 21% higher risk of lymphoma in those with tattoos, even after considering other risk factors like smoking and age. However, the study authors stressed that this finding is only an association, not a direct link, and further research is needed.
Surprisingly, the study found no increased risk with more tattoos. Co-author Christel Nielsen suggested this might be due to a low-grade inflammation caused by tattoos, but the exact reason is unclear.
Experts are sceptical. Dr. Timothy Rebbeck from Dana-Farber Cancer Institute and Harvard T.H. Chan School of Public Health said the conclusion is overstated, noting that the main risk factors for lymphomas are not related to tattoos. Dr. Catherine Diefenbach from NYU Langone Health Perlmutter Cancer Center also questioned the findings, particularly the lack of correlation with tattoo size.
The study authors speculate that if tattoos do increase cancer risk, it might be due to chemicals in the ink, which can travel through the body and accumulate in lymph nodes. However, other studies have found no significant risk, and infections from tattoos are rare.
The US FDA has issued guidance to ensure tattoo ink is not contaminated, following reports of contaminated inks. However, the FDA does not regulate tattoo practices or inks as they are considered cosmetic.
Nielsen’s team plans to investigate if tattoos are linked to other cancers or inflammatory diseases. Rebbeck advises that current research does not show a strong connection between tattoos and cancer.