3 ms·

This is actually really fascinating. If only humans had rings we could measure! To me the biggest finding is the lack of people 90-99 in the same areas. Wher

This is actually really fascinating. If only humans had rings we could measure! To me the biggest finding is the lack of people 90-99 in the same areas. Where are the supercentarians coming from with a lack of 90+ pipeline?

nearbuy 4y ago
Supercentenarians are people over 110 (centenarians are over 100). Only about 1 in 100,000 people live this long. Around 1 in 5 people live to 90. An order of magnitude more supercentenarians than average (through fraud or error) wouldn't make a noticeable difference in the number of people living 90-99, even assuming all supercentenarians were once counted as being 90-99.
- jedberg 4y ago
  Yes I understand that, but if you are saying some area is a "blue zone" where people tend to live longer, you'd expect an outsized number of 90-99 (and 100-109) for the same reasons that there are 110+, if those reasons are related to the geography (which is the claim with blue zones).
  - nearbuy 4y ago
    My understanding is the original authors of the blue zone study didn't actually check the number of people aged 90-99. They did look at life expectancy though, which was slightly higher for the blue zones. Not sure how to square that with the new finding of fewer people living 90-99 years.
  - anonymouskimmer 4y ago
    Wouldn't even geographic blue zones be subjected to geopolitical and economic shocks? These events would disproportionately impact people by age cohort.
    - kevinmchugh 4y ago
      This is my thought. Someone who's 110 had a different reality in front of them at age 20 than someone who's 90.
londons_explore 4y ago
After a person has died, I suspect science could measure their age pretty accurately with enough effort. For example, there are certain cells that don't multiply after birth (eg. some nerve cells). One could presumably date carbon atoms in their DNA... Or parts of the body that don't regenerate - like tooth enamel. I suspect with the right type of imaging, you'd probably find 'tree rings' in things like fatty deposits in arteries too.
- dontlaugh 4y ago
  Even cells that don’t multiply still accept nutrients. Pretty much no atoms in our bodies stick around for too long. It’s why carbon dating largely measures the time an organism died.
  - anonymouskimmer 4y ago
    Mineral deposits in our bodies (teeth and bones) are pretty good. In non-replicating cells DNA would be pretty good too. Some of it gets replaced as repairs occur, but most of it would not. I'm not sure that carbon dating would be very accurate over the lifetime of a person (though specific events could cause specific sorts of deposits in bones during the occurrence of those events). And even if it was, radioactive carbon, either because of damage, or because of electrochemical effects, would probably be replaced in DNA more frequently than non-radioactive carbon, as long as the organism was alive, even in non-replicating cells.
  - Ovah 4y ago
    This doesn't hold true for all cell types. There's a group in Sweden that has C14 dated the replication rate of some cell types. IIRC some cell types - some neurons and adipocytes - only replicate every 10 years or less. Their method has something to do with C14 from nuclear weapons: people who lived before they went off wouldn't have as much. And a lot of C14 would be from the uptake of nuke C14 since. IIRC pre-nuke people have adipocytes with C14 amounts compared to post-nuke people because those cells barely divide. That's what I picked up from a talk way back. I believe this is the same group. https://news.ki.se/new-neurons-generated-in-the-hippocampus-of-adult-humans https://news.ki.se/new-neurons-generated-in-the-hippocampus-...
user070223 4y ago
apperantly Dodo birds has marking on the bones[0] which researchers interpert it as time they struggled to find resources (simillar to tree where you move between wet and dry season). I guess one could cross reference times of femine to a skeleton with known lifetime to see if it shows up in humans as well. [0] https://youtu.be/Juci-kAqjes?t=219 https://youtu.be/Juci-kAqjes?t=219
ip26 4y ago
Maybe supercentarians are more likely when, for whatever reason, there aren’t any cheeky young upstarts breathing down their necks :)

nearbuy 4y ago

Supercentenarians are people over 110 (centenarians are over 100). Only about 1 in 100,000 people live this long. Around 1 in 5 people live to 90. An order of magnitude more supercentenarians than average (through fraud or error) wouldn't make a noticeable difference in the number of people living 90-99, even assuming all supercentenarians were once counted as being 90-99.

jedberg 4y ago
Yes I understand that, but if you are saying some area is a "blue zone" where people tend to live longer, you'd expect an outsized number of 90-99 (and 100-109) for the same reasons that there are 110+, if those reasons are related to the geography (which is the claim with blue zones).
- nearbuy 4y ago
  My understanding is the original authors of the blue zone study didn't actually check the number of people aged 90-99. They did look at life expectancy though, which was slightly higher for the blue zones. Not sure how to square that with the new finding of fewer people living 90-99 years.
- anonymouskimmer 4y ago
  Wouldn't even geographic blue zones be subjected to geopolitical and economic shocks? These events would disproportionately impact people by age cohort.
  - kevinmchugh 4y ago
    This is my thought. Someone who's 110 had a different reality in front of them at age 20 than someone who's 90.

londons_explore 4y ago

After a person has died, I suspect science could measure their age pretty accurately with enough effort. For example, there are certain cells that don't multiply after birth (eg. some nerve cells). One could presumably date carbon atoms in their DNA... Or parts of the body that don't regenerate - like tooth enamel. I suspect with the right type of imaging, you'd probably find 'tree rings' in things like fatty deposits in arteries too.

dontlaugh 4y ago
Even cells that don’t multiply still accept nutrients. Pretty much no atoms in our bodies stick around for too long. It’s why carbon dating largely measures the time an organism died.
- anonymouskimmer 4y ago
  Mineral deposits in our bodies (teeth and bones) are pretty good. In non-replicating cells DNA would be pretty good too. Some of it gets replaced as repairs occur, but most of it would not. I'm not sure that carbon dating would be very accurate over the lifetime of a person (though specific events could cause specific sorts of deposits in bones during the occurrence of those events). And even if it was, radioactive carbon, either because of damage, or because of electrochemical effects, would probably be replaced in DNA more frequently than non-radioactive carbon, as long as the organism was alive, even in non-replicating cells.
- Ovah 4y ago
  This doesn't hold true for all cell types. There's a group in Sweden that has C14 dated the replication rate of some cell types. IIRC some cell types - some neurons and adipocytes - only replicate every 10 years or less. Their method has something to do with C14 from nuclear weapons: people who lived before they went off wouldn't have as much. And a lot of C14 would be from the uptake of nuke C14 since. IIRC pre-nuke people have adipocytes with C14 amounts compared to post-nuke people because those cells barely divide. That's what I picked up from a talk way back. I believe this is the same group. https://news.ki.se/new-neurons-generated-in-the-hippocampus-of-adult-humans https://news.ki.se/new-neurons-generated-in-the-hippocampus-...

user070223 4y ago

apperantly Dodo birds has marking on the bones[0] which researchers interpert it as time they struggled to find resources (simillar to tree where you move between wet and dry season). I guess one could cross reference times of femine to a skeleton with known lifetime to see if it shows up in humans as well. [0] https://youtu.be/Juci-kAqjes?t=219 https://youtu.be/Juci-kAqjes?t=219

ip26 4y ago

Maybe supercentarians are more likely when, for whatever reason, there aren’t any cheeky young upstarts breathing down their necks :)