Not really [0], leaded gas was completely banned in the US in 1996 but really hadn’t been used since the early 80s and had start the phase out in 1996.
So you’d probably need to look at people in their 50s who really had an impact of lead from auto fuel.
Where "completely" in this case implies "for road-going vehicles". General aviation (largely small, piston-engine planes) still overwhelmingly run on 100 octane low-lead (100LL).
This is a very big deal if you spend time around small aircraft (hangar floors in particular sometimes have terrifyingly high lead levels.) But if you’re not spending time close to aircraft, the amount of lead you’ll be exposed to is negligible - at least compared to auto emissions, which were ubiquitous and extremely concentrated in residential neighborhoods. Unfortunately the lead remains in the soil, so there’s still exposure to it today.
Good point. I meant “completely” for consumer vehicles in the US. That’s what was pumping out all that lead into the air in the US. The other uses were much smaller.
On road use is banned. Also, the cost per gallon of leaded gas is at least $10/gallon now, which is a pretty large incentive enough for people not to use it :)
Basically most piston engine aircraft use Avgas 100LL (low lead solution). So the majority of the air traffic found at a typical municipal airport. Fortunately this is being phased out by the FAA in favor of unleaded.
Surely studies could get a good control group of people who grew up in rural Montana, or the Andes. Assume we can find groups with near-zero lifetime exposure to atmospheric (and/or waterborne) lead. What's their background rate of Alzheimer's?
