Tattoos increase risk of malignant lymphoma, study finds

A recent study published in the journal Clinical MedicineResearchers have determined the relationship between exposure to tattoo ink and the risk of malignant lymphoma and lymphoma subtypes.

study: Tattoos are a risk factor for malignant lymphoma: a population-based case-control studyImage credit: Charcompix / Shutterstock

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Tattoos have recently become popular, but the long-term health effects are unknown. Tattoo ink contains carcinogens such as polycyclic aromatic hydrocarbons (PAHs), primary aromatic amines (PAAs), and metals. Tattoo ink can trigger an immune response that causes the tattoo ink to migrate away from the injection site. The presence of tattoo pigments in lymph nodes has been proven, but the long-term health effects are unknown.

The reasons for the increasing incidence of lymphoma worldwide are unclear, and it is important to discover the link with lifestyle habits. Lymph nodes contain proliferating cells and are susceptible to carcinogens. Studies have shown that exposure to solvents, flame retardants, pesticides, and hair dyes is associated with immune disorders, which in turn play a role in the development of lymphoma.

About the Research

In this population-level study, researchers investigated tattoos as a risk factor for lymphoma and also evaluated the exposure-response relationship and the effect of exposure duration, taking into account the interval between first tattoo and index year (year of lymphoma diagnosis).

The researchers analyzed Swedish national authority registries to identify the occurrence of malignant lymphoma cases diagnosed using International Classification of Diseases, Third Revision codes in individuals aged 20 to 60 years between 2007 and 2017. They used incidence density sampling of the population-wide register data to randomly select three sex- and age-matched controls for each case.

The research team analyzed exposure using questionnaires sent by the Swedish government in 2021 and data on possible confounding variables from the registry. Respondents provided tattoo characteristics such as color, total area of ​​ink on the body surface, the tattooist's skill level, and geographic region where the tattoo was done, as well as the age at which they got their first tattoo. The researchers used multivariate logistic regression to calculate the incidence rate ratio (IRR) of malignant lymphoma in individuals with tattoos. Study covariates included education, family income, smoking, and marital status.

The researchers performed subgroup analyses to examine the association between tattoo exposure and lymphoma subtypes. They also performed sensitivity analyses to evaluate the confounding effects of hazardous occupations and use of immunosuppressants. They used the International Agency for Research on Cancer (IARC) classification to determine whether chemical exposure provided sufficient or limited evidence of lymphoma. They investigated the possibility of survivorship bias by including responses from next of kin of deceased patients in the study. To evaluate the possibility of reverse causation, they excluded people who got their first tattoo within one year of their cancer diagnosis.

Results and discussion

The sample population included 11,905 individuals, with response rates of 54% in cases (n = 1,398) and 47% in controls (n = 4,193). The prevalence of tattoos was 21% in cases and 18% in controls. Individuals with tattoos were at increased risk of developing lymphoma (IRR, 1.2). Individuals who reported less than 2 years between first tattoo ink exposure and lymphoma diagnosis were most likely to develop lymphoma (IRR, 1.8). Risk decreased with intermediate duration of tattoo ink exposure (3.0-10 years), but risk was elevated in individuals who had their first tattoo at least 11 years before the index year (IRR, 1.2).

The researchers found no indication of increased risk with increasing area of ​​tattoos across the body. Tattoo exposure was associated with the highest risk of developing diffuse large B-cell lymphoma (IRR, 1.3) and follicular lymphoma (IRR, 1.3). Sensitivity studies yielded similar results, demonstrating the robustness of the primary findings.

Laser therapy for tattoo removal appears to significantly increase the incidence of malignancies. The relative risk of lymphoma in tattooed patients who received laser therapy was 2.6 in a matched study. Asymmetric analysis revealed a significant modified effect (IRR, 3.0) of laser tattoo removal. This result may be due to the decomposition of azo-type compounds in tattoo inks into carcinogenic amines such as o-toluidine, 3,3'-dichlorobenzene, and 2-amino-4-nitrotoluene after laser irradiation.

The study found that people with tattoos were 21% more likely to develop lymphoma than those without. Tattoos that were done 0-2 years or more than 11 years before the index year may increase the risk of lymphoma. Exposure to tattoo ink may be associated with tumor initiation and progression, the latter with fairly rapid consequences. The toxicokinetics of tattoo ink suggest a time-dependent effect. The researchers noted that the highest risk was seen when the first tattoo was done less than 2 years before the index year, likely due to reverse causation. Laser therapy for tattoo removal resulted in much higher risk estimates. The long-term health effects of tattoo exposure and the impact of laser tattoo removal require additional research on potential public health implications. Findings indicate that people with tattoos may develop B-cell lymphoma, particularly diffuse large B-cell lymphoma and follicular lymphoma subtypes.

Regarding the mechanism underlying the association between tattoo ink exposure and malignant lymphoma, the researchers stated:We still don't know why this is the case. We can only speculate that tattoos, regardless of size, cause low-level inflammation in the body, which can lead to cancer. So, things are more complicated than we initially thought.”

Video – Link between tattoos and lymphoma revealed

Link between tattoos and lymphoma revealedplay