Professor Amy Spector

But that doesn't mean that the HRT prevented the dementia.

They might be more educated or have more access to other health care.

So what we need is these randomized controlled trials where we randomly assign people to either receive HRT or not.

And then we can really compare the differences in a more robust way.

Yeah, it's a really, really good point.

And that's one of the big problems.

Once something's been around for a long time, it becomes harder to do trials because we know more and more about both the benefits and also the potential risks.

So people may be more reluctant to sign up.

That's absolutely right.

And I suppose you might get a bias in the sense that the people who are signing up to these kind of trials are maybe the people who don't have such severe symptoms, who don't mind as much whether they get the treatment or the placebo.