Poor research doctors can't get any respect:
however doctors speculate that both “genetic and environmental factors” are involved (that’s doctor speak for we have no clue what the precise causative agent is).
It means that they haven't found a single definitive cause - there may not be one single cause. They have eliminated many possible causes. But some still show a possible link, just like this article. I'm glad scientists are exploring many possible links, even though they don't get The Answer on any of their studies. Go, science!
I know what it means, I say things like that in my own publications. :) Yeah, science is incremental, we don't need to get The Answer, we just need to get an answer, then explore that further!
I don't doubt that you know what it means. But the skeptics already do such a good job of saying that scientists don't have any idea of what's going on. And it's so easy for non-scientists to buy into that - especially if we reinforce that idea. (And don't even get me started on scientists saying they 'believe' something, rather than talking about following the evidence.)