At Yahoo!Answers I tackled this one recently , "How is epistemology and metaphysics related." I did so without even mentioning the issue of noun/verb agreement. What amazing restraint. So let me throw off the shackles of such restraint now and shout, "How ARE THEY, you mean, don't cha????"
Here, though, is my full and temperate answer.
They are related in somewhat circular fashion. Your view of epistemology, your view of how you know things, will likely depend upon some implicit or explicit metaphysics. If you think of yourself as a biological organism, in the midst of a dangerous world, forced to make the best available guesses in order to increase the chances of seeing tomorrow -- if you think of yourself that way, which is the premise of a lot of epistemological thought, you will already have made a number of metaphysical assumptions.
So on one hand we'd have to have a good idea of who and where we are to start thinking sensible thoughts concerning how we know. On the other hand (one might argue) we should have a good idea how we know before we can sensibly claim to KNOW who and/or where we are.
See the circle? Well ... some see it and some don't. This is philosophy. Everything is contested. even the possibility that the sensible world might be a Matrix.