The popularity of tattoos has increased sharply in recent years, affecting no less than 20% of the population in certain European countries and even 30% in the USA. However, tattoo inks, far from being harmless, are complex mixtures of organic and inorganic pigments, to which are added precursors and synthetic by-products, as well as various additives. The inks used often contain potentially carcinogenic substances such as primary aromatic amines, polycyclic aromatic hydrocarbons and various metals such as arsenic, cobalt, lead and nickel.
During tattooing, some of the ink migrates to the lymph nodes, leading to a systemic immune response and visible pigmentation, with deposits of metallic particles observed in long-term tattooees.
Could these observations be linked to the increase in cases of lymphoma?
To find out, a team of Swedish researchers conducted a case-control study including nearly 12,000 people aged 20 to 60 diagnosed with malignant lymphoma in Sweden between 2007 and 2017. A questionnaire aimed at determining their status tattoo was sent out, receiving responses from 54% of lymphoma patients (n=1,398) and 47% of controls (n=4,193). For each case, three controls matched by age and sex were selected. Multivariate logistic regression models were used to control for potential confounders.
The study included 11,905 individuals, with a response rate of 54% among cases and 47% among controls. The prevalence of tattoos was 21% among cases versus 18% among controls. Tattooed individuals had an increased risk of malignant lymphoma (IRR = 1.21; 95% CI 0.99–1.48). This risk was particularly high for those who received their first tattoo less than two years before the index year (IRR = 1.81; 95% CI 1.03–3.20), decreased for intermediate exposures (three to ten years), and increased again after eleven years (IRR = 1.19; 95% CI 0.94–1.50). No significant association was found between tattooed area and risk. The most commonly affected lymphoma subtypes were diffuse large B-cell lymphoma (IRR 1.30; 95% CI 0.99–1.71) and follicular lymphoma (IRR 1.29; 95% CI 0.92–1.82).
This study indicates that tattoos may be associated with an increased risk of malignant lymphoma. Further research is needed to confirm these findings and establish a causal relationship. Furthermore, this study highlights the need to regulate the chemical composition of tattoo inks and to deepen our understanding of the pathobiological mechanisms linking tattoos to cancer.
Before this research, only one study had addressed the link between tattoos and lymphoma risk, but this lacked statistical robustness. This new study is the first to use a large sample and population-based approach to analyze this association.
Nielsen, C., Jerkeman, M., & Saxne Jöud, A. (2024). Tattoos as a risk factor for malignant lymphoma: a population-based case–control study. eClinicalMedicine, 72, 102649. https://doi.org/10.1016/j.eclinm.2024.102649
