Maybe I'm just a skeptic....

[malkin]

I re-read the earlier threads just now and see that you are a speech pathologist.

How does one abuse their voice? Practicing the 'command' voice where they lose their voice, then get it back in a deeper, and scratchier, version of what they used to have?

It can lead to cancer? OMG!

Yes.
On all counts.

The cancer connection is not well established, especially in comparison to the big obvious cancer risks like tobacco use.

Cancer aside, imagine Jillian as a trainer in a noisy gym---but aphonic, that is, completely unable to make a sound from her voice! Bummer!

But straining pitch up or down, or pushing volume or simple over use can cause damage. It really isn't surprising when you remember that the vocal folds are really pretty tiny little bits of tissue performing a remarkable function.

More info here: http://www.asha.org/public/speech/disorders/voice.htm