Sweden’s population has become one of the most tattooed in Europe, but at the same time, the incidence of melanoma is increasing, with a recent epidemiological study now suggesting a link between the two, according to researchers from Lund University in Sweden.
State of research on tattoos and cancer
In view of the lack of knowledge concerning the long-term health effects of tattoos, and its position as an under-researched field, the study team has been examining potential links between the decorative inking and cancer.
The first study, published in 2024, showed a possible link between tattoos and lymphoma, but in a second study published this year, the researchers did not find any association between tattoos and squamous cell carcinoma of the skin.
Increasing number being inked
Around 20% of all Swedes have been tattooed, the figure rising to more than 40% in women under 40. Most get their first tattoo between the ages of 18 and 35 but some are even younger, which means almost a lifetime of exposure to tattoo ink.
At the same time, the incidence of melanoma has risen considerably over the past 30 years, due to causes such as increased UV radiation – but exposure to chemicals is also a suspected factor. Each year, around 5 000 Swedes are diagnosed with melanoma.
“We don’t know about the long-term health effects of tattoos. We therefore need to clarify if there is a link between tattoo ink and skin cancer,” said Christel Nielsen, associate Professor and researcher in Epidemiology at Lund University.
Study design
Using the National Cancer Register, the researchers identified 2 880 individuals who have been diagnosed with melanoma between the ages of 20 and 60. These people were then each matched with three individuals from the Total Population Register of the same sex and age but without a melanoma diagnosis.
The researchers subsequently collected information via questionnaires about whether the participants were tattooed, and controlled for other factors such as sun exposure, sun bed use and skin type.
Using this study design, they could estimate the risk of melanoma among tattooed participants in comparison with non-tattooed individuals and also ensure that the results were not due to other factors like sun exposure and sun bed use.
Increased relative risk at group level
“Of those who had melanoma, 22% were tattooed, compared with 20% in the control group. But when we took lifestyle factors that might distort the association into account, we saw a 29% increased relative risk among tattooed people,” said Emelie Rietz Liljedahl, associate researcher in Toxicology at Lund University.
This applies at group level but not at individual level. The results suggest that tattoos could be a risk factor for melanoma, but further studies are needed before it is possible to talk about a causal link, the team said.
The impact of tattoo ink
When tattoo ink is injected into the skin, the body perceives it as a foreign substance, meaning the immune system is activated. The ink pigments are encapsulated by the immune cells, which hold them in place and transport them via lymphatic fluid to the lymph nodes.
“Azo pigments are the most common organic colourants in tattoo ink. This could be a potential risk because we already know these can break down into harmful chemicals that may cause cancer. This particularly applies for exposure to UV radiation from the sun, sun beds or laser treatments,” added Liljedahl.
Regulation of inks
The tattoo ink market was relatively unregulated until 2022, when an addition to the EU’s chemical legislation (REACH) came into effect and introduced concentration limits for chemicals in tattoo ink.
Despite this, market surveillance has shown that inks may still contain toxic chemicals exceeding the maximum limits, noted Liljedahl.
“In parallel with the authorities’ continuing work on regulating the market, we need to understand the potential mechanisms through which tattoos may increase the risk of disease. As epidemiologists, our role is to find patterns in the population. Follow-up studies are now needed to examine why these patterns arise,” said Nielsen.
The constantly rising tattoo trend means that the results of the study are more relevant now than ever from a public health perspective.
Along with the researchers’ previous findings about a possible link between tattoos and lymphoma – but the absence of an association with squamous-cell carcinoma of the skin – the latest study takes us one step further in understanding how tattoos may affect our health.
Exploring links to autoimmune conditions
“Our results indicate there may be something that happens in the immune system, so we will continue exploring possible links between tattoo exposure and autoimmune conditions, such as psoriasis and thyroid conditions, in which the immune system is also involved,” Nielsen said.
Study details
Does tattoo exposure increase the risk of cutaneous melanoma? A population-based case-control study,
Emelie Rietz Liljedahl, Kari Nielsen, Malin Engfeldt, Anna Saxne Jöud, Christel Nielsen.
Published in the European Journal of Epidemiology on 24 November 2025
Abstract
The incidence of cutaneous melanoma (CM) has risen sharply over the past 30 years, coinciding with the rapidly growing tattoo trend. In Sweden, 20% of the population is tattooed. Repeated reports of the presence of carcinogenic chemicals, such as polyaromatic hydrocarbons, aromatic amines and heavy metals in tattoo ink justifies the investigation of CM risk in relation to tattooing. We aimed to investigate the potential association between tattoo exposure and CM. We identified 2880 individuals who were diagnosed with CM at age 20–60 years, in the Swedish National Cancer Register. For each case, we sampled three random age- and sex-matched controls from the Swedish Total Population Register.
Exposure data and data on potential confounders were collected through a questionnaire in 2021. We estimated the relative risk of CM in tattooed compared with non-tattooed individuals using multivariable logistic regression, rendering incidence rate ratios (IRR). Of the participants, 22% of the cases (354/1598) had a tattoo before the index date, vs. 20% of the controls (815/4097). We observed an adjusted relative risk of CM in tattooed compared to non-tattooed individuals of 1.29 (95% confidence interval [CI]: 1.07–1.56). The results suggested that tattoos may be a risk factor for CM, but further studies are needed to establish causality.
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