I have to wonder if the study is bullshit. Take the "power lines cause cancer" study.
That study "proved" that power lines caused cancer because the people that lived closer to them had a higher rate of cancer.
The someone put a little thought into it and realzied that the land next to power lines was land that people didn't want. Thus that land was low rent and poor people tended to live there. So it was that poor people, that tended to smoke more, was the cause for higher higher cancer rates.
I have nothing to back it up, but I'm willing to bet that poor people tend to get more, and bigger, tattoos. I can't see Bill Gates or Warren Buffet walking around sporting a sleeve.
Lol, I can almost gaurantee that if the FDA has anything to do with this, that it's got nothing to do with the fact that the tattoo ink can give you cancer.
Keep in mind that this is the same FDA that will feed you all kinds of chemical additives known to be related to the growth of cancer just to keep profits circulating.