[throwaways85989]

Is the blue a reference to the phrase turning grandpa "blue" for pension aka keeping him post natural mortem in the freezer?

Several countries on this list are "low" trust societies?" so the data could be explained very well with it.

https://www.youtube.com/watch?v=404IeUzGNZ4

[IncRnd]

"They are called Blue Zones because when Buettner and his colleagues were searching for these areas, they drew blue circles around them on a map." [1]

[1] https://www.healthline.com/nutrition/blue-zones

[xcskier56]

No, the author, Dan Buettner has a consulting practice around helping companies, orgs, municipalities implement the lessons from Blue Zones to help build healthier environments. https://www.bluezones.com/ Where the Blue came from I'm not sure.

[klyrs]

My mind went to "blue haired grannies" https://tvtropes.org/pmwiki/pmwiki.php/Main/ElderlyBlueHaire...

[bks]

This ^^ https://www.mentalfloss.com/article/643186/why-old-ladies-ha...

[fredski42]

I believe it was because those areas were marked on a map using a blue marker.