Re: How does this compare?
I think the comparison between veterans and rookies is compelling enough to suggest that it's not being in space, but dealing with the stress-related effects on the immune system, and YES compare this to other high stress professions like the military, police, fire, ambulance, and trial lawyers. Yeah, no kidding!
This is the kind of study that would make an _outstanding_ doctoral thesis for med students. The effects of stress and inexperience in a high stress occupation, not just space itself, on blood chemistry and the immune system, and *IS* space *REALLY* a factor?