Tattoo ink exposure is associated with lymphoma and skin cancers
56 comments
·March 4, 2025perdomon
belter
Here is another study.
"Possible association between tattoos and lymphoma" - https://news.ycombinator.com/item?id=40489486
woleium
Usually when studies are flawed like this there is someone with a vested interest in the outcome paying. I can’t imagine who that may be here though. Anyone have any suggestions?
flir
I wonder if tattoo removal bumps the risk even further - a bit like disturbing asbestos in a building. That would be a hard one to study.
arisAlexis
Laser drives all the chems through your kidneys and bladder. Removing the upper skin layer could be safer ?
krisoft
> Removing the upper skin layer could be safer ?
Tattoos are not in the upper skin layer though. Also removing any skin layers is quite dangerous, at least in a statistical sense.
mordechai9000
There is a technique called salabrasion where the upper skin layers are rubbed off with a paste of salt. This doesn't remove the tattoo, but the ink is at least partially drawn up into the resulting scab during the healing process. It's probably not very safe, despite the use of salt, and removing skin like that over even a moderate area sounds brutal, but apparently it works well enough. And then, after one or more repetitions of the process, you are left with a highly visible scar, and maybe a faint tattoo, instead of just a tattoo.
jan_Inkepa
Yeah - if there was just a risk of having one I'd probably get mine removed, but yeah - I think I remember looking into it once and coming away thinking it's probably best to leave it as is. (I can't remember the details).
metayrnc
> 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 individuals (95% CI: 1.08–2.41)
awestley
If lifestyle differences are not accounted for, I'd put little stock in this.
queuebert
That's the entire point of twin studies and case controls. Did you read the article?
theamk
no, that makes no sense. How does having identical genetics negate problem of different lifestyles?
Even the authors agree with awestley:
> Additionally, having a tattoo, especially among adolescents, has been suggested as an indicator of risky lifestyle highly associated with e.g. smoking [4] and alcohol consumption [46] – both risk factors of certain cancer types. Hence, evidence of an association between tattoo ink exposure and occurrence of cancer may be confounded by other health-related lifestyle factors. We intend to exploit the remainder of the information gathered in the survey in the future.
Indeed, it does seem like a big problem that should really be accounted in the initial analysis.
mbreese
Twin studies can help control for things like genetics and environmental factors in childhood (exposures, socio-economic factors, etc). They can't control for lifestyle choices made by adults. So, if a person has tattoos, are they more likely to smoke? To have sun exposure? To drink heavily? All of these factors would need to be addressed to see how confounding they are to having a tattoo.
You could also look at tattoo coverage, as in how much of the body is covered in ink? Would a small tattoo on the shoulder have as much risk as a full back tattoo? There are a lot of extra confounders here that could be better explored, but it gets difficult to get a full dataset. However, given their survey data, they should have more analysis options with more time.
The lack of confounder analysis is a bit surprising, but perhaps the paper was long enough already.
hmmokidk
As someone with tattoos I am spending a lot of time in the sun without sunscreen and smoke enough nicotine to satiate some region in france probably.
nerdjon
It would be interesting if they could somehow look at the ink itself but without this being basically a lifelong study I realize that could be difficult.
Especially given the recent report of issues with some ink being used. I don't remember the specifics.
I doubt this would stop people from getting tattoos, and I know it isn't stopping myself from planning on being fully covered... but it is still interesting.
harimau777
It would be interesting to see if this applies to traditional tattoo inks as well. Are tāmoko still done with traditional inks? If so, then that might be an easy way to do a population study.
jl6
Associated with. Causal connection not yet proved. On the other hand, let’s be realistic, tattoos are not going to turn out to be good for you, are they.
code_runner
People have been getting tattoos for a pretty long time. I don't really see this as stopping that?
If you have tattoos its entirely possible you'll actually be more careful in the sun by applying sunscreen.... but you also might be more prone to showing your ink off and therefore exposing a greater area of skin to the sun.
If there is some common ingredient that has been used in tattoo inks recently and we're concerned about that, let me know.... but generally speaking I don't think this is interesting information
swatcoder
It's mostly only here on HN where people (in their commenter persona) take this kind of study so seriously and pretend that they must either live uncompromising teetotaling lives in pursuit of optimal and maximally long health, or that the study has to be nonsense/misleading.
In reality, all of us live lives that put at greater risk of this and lesser risk of that. The real value of learning that there's perhaps some association with one of our activities and a specific disease or other kind of harm is that we can be watchful of that disease or harm emerging in our own lives and thereby give ourselves more opportunity to respond. Or perhaps we might use it as reason to moderate, or to finally stop doing something we already feel conflicted about.
So this kind of thing is definitely interesting information for some people, but as often for HN, we can expect a lot of comments engaging with it only in extremes of condemnation or refutation.
binoct
Scientific research doesn’t have to directly impact personal decision making to be useful and interesting. This study provides a data point suggesting a link between having tattoos and skin cancer - it’s certainly interesting to the medical field to better understand what increases the risk of cancer. A lot of research into smoking cigarettes and cancer also didn’t have much impact on people who decided to smoke, but it was also valuable knowledge.
wiether
> If you have tattoos its entirely possible you'll actually be more careful in the sun by applying sunscreen.... but you also might be more prone to showing your ink off and therefore exposing a greater area of skin to the sun.
Knowing multiple tattoo artists, that's exactly what they observe from their customers : some are very careful about their skin exposure while other are doing the exact opposite.
They are not healthcare professionnal so they don't study skin cancers, but they can easily tell which one is which based on how the tattoo evolve year after year.
This could probably be the easiest factor to check.
Regarding the inks, since there's little to no regulation, even in the EU, and people tend to get tattooed when away from home, it could be much, much trickier.
kurthr
Most inks up until the 20th century were carbon black (some vermilion and prussian blue). That changed with the introduction of both organic and inorganic color dyes over the last 100 years. Only recently has there been much regulation at all.
tattooPAH
Ink composition and regulation might vary regionally. The original article mentions
> The most frequently used tattoo ink is black. Black ink typically contains soot products like carbon black, which is listed as possibly carcinogenic to humans (mainly based on studies of carbon black inhalation and risk of lung cancer) by the International Agency for Research on Cancer (IARC) [13]. Through the incomplete combustion used for carbon black production, polycyclic aromatic hydrocarbons (PAHs) are formed as byproducts. One of the most dangerous of these is benzo[a]pyrene (BaP), which is classified as carcinogenic to humans by the IARC [14].
You really don't want benzo[a]pyrene floating around your system, it's a potent carcinogen that's been firmly established by many studies. Some papers focus on directly on PAHs and tattoos, for example this PLoS One 2014 paper: https://pubmed.ncbi.nlm.nih.gov/24670978/
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spiderxxxx
I don't think the result of this study would stop people from getting tattoos, but if you're on the fence, then perhaps it could sway you. Either way, it can provide information to doctors to perhaps screen them more often for skin cancer, or people to get screened, given that it might show a higher risk.
ceedan
> you also might be more prone to showing your ink off and therefore exposing a greater area of skin to the sun.
Seems likely
anarticle
Care and feeding of tattoos is largely a new thing. The vast majority of people do not care.
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tyronehed
In life it's often more important what you don't do, then what you do do
The study's conclusion that tattoo ink causes cancer fails to convince due to major methodological flaws. The sample sizes for the most important analyses (matched twin pairs) were tiny, with fewer than 5 informative pairs for lymphoma. Meanwhile, known lymphoma risk factors like viral infections, alcohol consumption patterns, and occupational exposures weren't properly controlled for. What we're likely seeing is correlation driven by lifestyle clustering - people with tattoos often have different behavioral patterns that independently affect cancer risk, but the study's crude "ever/never" smoking measure and absence of other key controls can't disentangle these complex relationships.