It's just a "casual" connection, yes. Some studies found no link in their populations. Some showed possibility to probability. Like all "causes," not clear-cut.
Hubby took it as an 18 year old. Never developed gut issues, but boy, that drug dried him out something fierce and he had to avoid the sun like the plague! His skin literally was flaking off, huge flakes, and he was crazy light sensitive (though those are common side effects). I'd be more worried about the drying effect with the lack of large bowel and our risk of dehydration.