True kelly, however there are so many things that go along with CDing ... trying to be thin, (weight control) ... keeping body toned to prevent "bat wings" under your bra, ( exercise at the gym ) ... basic skin care ( makes foundation go on easier ) and the list goes on.
So while crossdressing in and of itself may not contribute to a longer life, the requirements of making a good presentation of yourself mean taking care of yourself , ... means good health, ... means live longer.
I just don't see any downside to this. Except for my very thin wallet.