There have been studies showing a correlation between IQ levels and longevity. Here’s a study suggesting that a higher IQ, even when measured in children, is associated with longer life. This seems independent of quality of education or socioeconomic conditions.
Another study seems to corroborate
IQ and death: why smarter people live longer - Ness Labs.
Could this also explain the conundrum of why ex presidents have consistently longer lifespans?
Are Presidents really that intelligent!?!?
Well, maybe not, but almost all are graduates of Ivy League schools and have post college degrees as well.
I’m particularly curious about the notion of a shared genetic locus.
I think that the topic of intelligence and longevity is one of those “third rail” type of things that we’re just never going be able to discuss without most people getting pissed off. Remember, 50% of the population has below median intelligence.
And by the way, I’m not a super-smart guy myself. I like having a realistic understanding lf my abilities, so I’ve tested my IQ professionally a few times. Let’s just say I’m no genius. 
“Think about how how stupid the average person is. Then realize that half of 'em are even stupider than that.” - George Carlin
I think its very confounded… Childhood trauma and poverty and the related high cortisol and glucocortioid levels can probably lower iq at the same time they are shortening lifespans…
Research:
Conclusion
Early exposure to adverse experiences increases the child’s vulnerability to attention deficit and externalizing behavior with negative impact on IQ scores especially performance IQ.
Repeated measures of IQ were analyzed as a function of childhood trauma and group, controlling for confounders. There were significant differences in the impact of childhood trauma on IQ across the 3 groups. Exposure in HCS was associated with a nearly 5-point reduction in IQ (−4.85; 95% confidence interval [CI]: −7.98 to −1.73, P = .002), a lesser reduction in siblings (−2.58; 95% CI: −4.69 to −0.46, P = .017)
Adverse childhood experiences (ACEs) can have a tremendous impact on future violence victimization and perpetration, and lifelong health and opportunity. CDC works to understand ACEs and prevent them.
Stupid people make stupid choices…
Nah… probably because they get a lot more money after being president…and a better social life, similar to how Academy Award Winners (might) live longer:
Couple issues I have with this kind of thinking:
First: the vast majority of stupid people don’t think they’re stupid. As humans, we’re sort of wired to always assume we’re right and that others are wrong. That means that I might be stupid, too, and not realize it.
Second: stupid people can’t just decide to be smart . . . it’s not like being overweight or something. We can choose to read more or learn more about the world, but we can’t really raise our IQ much.
Stupid people aren’t to blame for being stupid; it’s not their fault. There’s no point in mocking them or looking down on them for it. If my kid had a low IQ, I’d love him just as much . . . that’s how I’m trying to teach myself to look at everyone else in the world, too.