Population-based case-control study of tattoos as a risk factor for malignant lymphoma

The popularity of tattoos has increased dramatically over the last few decades. Tattoo ink often contains carcinogenic chemicals. A case-control study in Sweden investigated the association of tattoos with risk of malignant lymphoma. Three random age- and sex-matched controls per malignant lymphoma patient were included. The study population consisted of 11,905 individuals. The tattoo prevalence was 21% among cases and 18% among controls. Tattooed individuals had a higher adjusted risk of overall lymphoma (incidence rate ratio 1.21; 95% CI 0.99-1.48), with the highest risk in individuals with less than two years between their first tattoo and the index year (1.81; 1.03-3.20). There was no evidence of increasing risk with a larger area of total tattooed body surface. The risk associated with tattoo exposure seemed to be highest for diffuse large B-cell lymphoma and follicular lymphoma. The authors conclude that these findings suggest that tattoo exposure was associated with an increased risk of malignant lymphoma.