Swedish Study Links Tattoos to a 29% Higher Risk of Cutaneous Melanoma

The incidence of cutaneous melanoma has risen markedly over the past 3 decades, largely attributed to ultraviolet (UV) radiation exposure. However, increasing interest has focused on potential chemical risk factors, such as tattoo ink. This population-based case-control study investigated whether tattoo exposure is associated with an increased risk of cutaneous melanoma.¹

Background

Tattoos have become increasingly common worldwide; in Sweden, approximately 20% of the population is tattooed, with prevalence exceeding 30% among individuals younger than 40 years.² Tattoo inks contain a variety of chemical compounds, including polyaromatic hydrocarbons, aromatic amines, and heavy metals—some of which are recognized or suspected carcinogens. These concerns, combined with growing tattoo prevalence, have prompted investigation into possible long-term health risks associated with tattoo exposure.

Methods and Materials

Investigators of the nationwide case-control study identified individuals aged 20 to 60 years diagnosed with cutaneous melanoma or melanoma precursor lesions in 2017 using the Swedish National Cancer Register, which has more than 99% coverage and morphological confirmation for the majority of skin cancers. A total of 2880 cases were initially identified. For each case, 3 age- and sex-matched controls were randomly selected from the Swedish Total Population Register using incidence density sampling. Ultimately, questionnaire responses were obtained from 1598 cases and 4097 controls.

Exposure and covariate data were collected through a structured questionnaire administered in 2021. Patients were asked about tattoo exposure, including age at first tattoo, number of tattoo sessions, body surface area tattooed, ink colors, tattoo location, and whether tattoos had been removed. Tattoos were defined broadly to include decorative tattoos, cosmetic tattoos such as permanent makeup or microblading, and medical tattoos used in reconstructive procedures. The questionnaire also collected information on potential confounders, including sun exposure, history of sunburns, tanning bed use, smoking, socioeconomic factors, and phenotypic characteristics such as skin type and reaction to sun exposure.

The primary outcome was overall cutaneous melanoma, including both invasive melanoma and precursor lesions such as melanoma in situ and melanocytic nevi with severe atypia. Multivariable logistic regression models were used to estimate the association between tattoo exposure and melanoma risk, expressed as incidence rate ratios (IRRs). Overall tattoo prevalence among study participants was 21%. Among cases, 22% reported having a tattoo before the index date compared with 20% of controls. The median age at first tattoo was similar between cases and controls (24 and 25 years, respectively). Most tattoos were decorative and performed by professional tattoo artists in Sweden.

Results

After multivariable adjustment, tattooed individuals had a 29% higher risk of cutaneous melanoma compared with nontattooed individuals (IRR, 1.29; 95% CI, 1.07-1.56). In analyses restricted to individuals with a first melanoma diagnosis, the association remained but was slightly attenuated (IRR, 1.23). The increased risk was observed across several melanoma subtypes. For invasive melanomas, the adjusted IRR was 1.25, whereas for in situ lesions, the IRR was 1.33. Subtype analyses showed higher estimates for superficial spreading melanoma (IRR, 1.40) and melanocytic nevi with severe atypia (IRR, 1.39).

Additional analyses examined tattoo characteristics and exposure duration. No clear dose-response relationship was observed for tattoo size, as larger tattoos were not associated with higher melanoma risk. Tattoo color appeared to have some influence; individuals with tattoos containing both black/grey and colored pigments showed a higher risk compared with nontattooed individuals. However, statistical power for certain pigment categories was limited. Individuals with 10 to 15 years of tattoo exposure showed the highest risk estimates, although elevated risks were also observed in those with shorter exposure durations.

UV Exposure Correlation

The study also explored potential interaction between tattoo exposure and UV radiation, given that UV exposure can accelerate pigment degradation into carcinogenic aromatic amines. However, no statistically significant interaction between tattoo status and cumulative UV exposure was detected. Similarly, the anatomical correlation between tattoo location and melanoma site was weak; only 30% of tattooed cases had melanomas at the same anatomical location as their tattoo.

Sensitivity analyses confirmed the robustness of the findings. Adjusting for childhood sunburn slightly increased the risk estimate, whereas excluding individuals on immunosuppressive medications strengthened the observed association. Excluding individuals with high-risk occupations or previous melanoma diagnoses did not materially change the results.

Final Thoughts

Several biological mechanisms could plausibly explain the association. Tattoo pigments may contain carcinogenic chemicals capable of initiating or promoting tumor development. Chronic inflammation induced by repeated skin puncture or pigment deposition may also contribute to carcinogenesis. Additionally, tattoo pigments can migrate to regional lymph nodes and potentially influence immune responses. The authors also suggest that immunotoxic effects of tattoo ink could play a role, particularly given the strong immunologic component of melanoma development. Although the trial findings do not establish causality, they highlight the need for further epidemiologic and mechanistic research to better understand the potential carcinogenic effects of tattoo pigments and long-term health implications of tattooing.

References

1. Rietz Liljedahl E, Nielsen K, Engfeldt M, Saxne Jöud A, Nielsen C. Does tattoo exposure increase the risk of cutaneous melanoma? a population-based case-control study. Eur J Epidemiol. 2025;40(12):1441-1453. doi:10.1007/s10654-025-01326-6

2. Nielsen C, Andréasson K, Olsson H, Engfeldt M, Jöud A. Cohort profile: the Swedish tattoo and body modifications cohort (TABOO). BMJ Open. 2023;13:e069664. doi:10.1136/bmjopen-2022-069664