Tattoo ink exposure is associated with lymphoma and skin cancers – a Danish study of twins

Abstract

AbstractWe aim to study the possible association between tattoo ink exposure and development of certain cancers in the recently established Danish Twin Tattoo Cohort.Tattoo ink is known to transfer from skin to blood stream and accumulate in regional lymph nodes. We are concerned that tattoo ink induce inflammation at deposit site that may eventually become chronic and increase risk of abnormal cell proliferation, especially skin cancer and lymphoma.We conducted two designs of study in twins in order to improve confounder control: A cohort study of 2,367 randomly selected twins and a case-control study of 316 twins born in the period 1960-1996. Cancer diagnoses (ICD-10) were retrieved from the Danish Cancer Registry and tattoo ink exposure from the Danish Twin Tattoo survey from 2021. The analysis addressed effects of time-varying exposure.In the case-control study, individual level analysis resulted in a hazard of skin cancer (of any type except basal cell carcinoma) that was 1.62 times higher among tattooed (95% CI: 1.08-2.41). Twin-matched analysis of 14 twin pairs discordant for tattoo ink exposure and skin cancer show HR=1.33 (95% CI: 0.46-3.84). For skin cancer and lymphoma, increased hazards were found for tattoos larger than the palm of a hand: HR=2.37 (95% CI: 1.11-5.06) and HR=2.73 (95% CI: 1.33-5.60), respectively. In the cohort study design, individual level analysis resulted in a hazard ratio of 3.91 (95% CI: 1.42-10.8) for skin cancer and 2.83 (95% CI: 1.30-6.16) for basal cell carcinoma.In conclusion, we are very concerned that tattoo ink interacting with surrounding cells may have severe consequences. Further studies are needed beneficial to public health – the sooner the better.