rather, it's about having a genetic predisposition to grow fat on your butt and thighs
Wow, the Smoking Lesion Problem in real life. EDTists will eat a lot in order to get a fatter bottom, whereas CDTists won't. :-)
The religion and retirement things are ones I've read about before and believe; the school, first-born, and altitude seem plausible; the big butts and flying strike me as dubious.
Flying makes sense to me. The bottom 30k feet of the troposphere blocks a lot more potentially carcinogenic radiation than the aluminum skin of an airplane does, and the top 10% of all commercial flyers put in a /lot/ more hours in the stratosphere than the vast majority of the population.
Assuming it's a genuine effect, it could be due to other factors: for example nightshift work is associated with reduced lifespan and increased cancer rates, apparently because of disrupted circadian rhythms - and flying across timezones is pretty darn disruptive too.
This could be tested by looking at people who fly a lot in a north-south direction (if there are any), who would get cosmic rays but no jet lag. In any event, the flux of cosmic rays is pretty much known, so the total exposure such people get can be computed and compared to that of radiation workers etc.
isn't it rather than going to church can extend your life - which can translate to having a social network that is supportive and shares a common ethic can extend your life. not going to church shortening your life is a leap i think.