Could a Tattoo Raise Your Risk of Skin Cancer? Twin Studies Suggest a Link.

A twin study suggests the consequences of getting a tattoo could be worse than potential regret, finding tattooed twins more likely to develop skin cancer or lymphoma than their tattoo-free siblings.

University of Southern Denmark biostatistician Signe Bedsted Clemmensen and colleagues used two different study designs to analyze cancer diagnoses and tattoo patterns.

A cohort study of 2,367 randomly selected twins compared individuals who had a form of skin cancer with those who didn't, revealing those who had tattoos had nearly four times the risk of skin cancer.

Their case-control study compared 316 individuals with their twin siblings, finding between 33 and 62 percent greater risk of a tattooed twin going on to develop cancer.

This was more pronounced for those with tattoos larger than their palm – a risk three times higher than those without tattoos.

It's important to note, firstly, that cancers like lymphoma are quite rare, so this increase is from a low baseline.

What's more, this is not evidence that tattoos cause cancer. It may be those who get tattoos are more at risk of cancer thanks to factors related to a decision to get tattoos.

But previous research has also found higher risks of lymphoma in people with tattoos than in those without, so these findings call for further investigation.

"In our study, we do not see a clear link between cancer occurrence and specific ink colors, but this does not mean that color is irrelevant," explains Clemmensen.

"We know from other studies that ink can contain potentially harmful substances, and for example, red ink more often causes allergic reactions. This is an area we would like to explore further."

Humans have been using their bodies as a canvas for thousands of years, a practice that's been increasing in popularity in recent decades. But we still don't know much about the long-term health consequences.

"We can see that ink particles accumulate in the lymph nodes, and we suspect that the body perceives them as foreign substances," explains Odense University hematologist Henrik Frederiksen.

"This may mean that the immune system is constantly trying to respond to the ink, and we do not yet know whether this persistent strain could weaken the function of the lymph nodes or have other health consequences."

A 2016 report for the European Commission found the majority of inks used in tattooing are not even approved for use in cosmetics, and some are known to be carcinogenic during degradation.

If you are considering getting inked, it is worth carefully considering ink types and checking if you are clear of other health conditions, such as psoriasis, that tattooing may exacerbate.

Research like this can be a powerful tool to inform us of potential risks, though these studies have limitations.

Comparisons could only be based on individuals who had survived cancer, for example. Weighing up the results also requires consideration of the relatively small number of twins and the low baseline for cancer diagnoses.

"The extent of the impact on the immune system should be further investigated so that we can better understand the mechanisms at play," says Clemmensen.

This research was published in BMC Public Health.