What does "prevalent undiagnosed disease" mean?

What inverse association? Are we supposed to guess what this is about?

prevalent in this case means "widespread". An example of a prevalent undiagnosed disease state is high blood pressure. Lots of folks have it but don't know it.

That's true, but the researchers are looking at a hypothetical case (the supposed existence of a prevalent disease) and concluding that the results they showed were not attributable to that.

Thank you both

Personally, I think this is a darn good question.

JPB is probably right, but it also kind of sounds like the author wasn't paying attention to what he was saying.

You didn't read my post, then.

Every condition has a prevalence -- the rate it occurs in the population. In research lingo, a prevalent condition is one that is widespread - has a high prevalence. If something is known to be fairly prevalent it's because it's detected in a large number of people who are tested/treated for it. That observation is then projected onto the population at large (people who haven't been tested for it) and a rate of undiagnosed prevalent disease is calculated. McTag is right --- it's a hypothetical number that is derived from observation of a subset of the population.

There's insufficient info in the OP to know what disease we're talking about here, but the authors are stating that there's no evidence that there is a high undiagnosed rate in the general population that might explain their results. It gives their conclusions more weight because they're saying they've accounted for the possibility that their observation is due to "noise" amongst the subjects.

Thank you JPB.
And thanks to all others.

I think it is not necessary to upload the whole article to make the matter certain.

Because I think the importance of the article is not significant.