Usually if you have a job that requires you to work in shifts, you're more likely to be less educated and have other habits (smoking, drinking, unhealthy diet) that would be likely to decrease your lifespan. So I'm not sure if they've determined that shift work directly shortens your life. I'd like to know since I have worked in shifts for most of my career.
I would like to know as well. I worked shift duty in the USAF, and currently do storm duty for the electric utility company.