As I said initially, my memory is that it was a long time ago. I doubt
it's as true today for MDs, but it is an example of ego overcoming
common sense. That was my initial point, and in the context of this
post, still valid. You asked for a reference, and I gave you one. A
more careful examination may refute it. I would estimate it may
approach statistical significance. It certainly cannot be rebutted
with hand waving.