I'll have to disagree Mike, only because I've tried them and had blood work done.
Dbol at 10mgs per day taken upon waking was the only thing which did not disrupt my HPTA.
I hear all the talk about winny and anavar bridges, but even as mild as they are, they're too suppressive of compounds.
You make a good point about using arimidex with the dbol, but if I remember correctly I don't think I used any during that period of time. If anything I would suspect the arimidex would drive estrogen too low further inhibiting HPTA function.