Does tattoo exposure increase the risk of cutaneous melanoma? A population-based case-control study

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 nontattooed 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 nontattooed 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.