"tell me what caused it then"

Read your own post.....

"The exact causes of bladder cancer are not clear"

"which suggest a link"
And the key word there is SUGGEST.... We simply don't KNOW yet.... Hopefully one day we will.

So keep donating $$ to cancer research
Quit smoking
Get some exercise
Eat a ballance diet
Support the ban on smoking in public spaces. (Smoking in a car or house where children are passangers/residents should be classified as child abuse if you ask me!)

You'll still drop dead someday.... but maybe it won't be cancer that gets you.