Hmm, thanks for the good question. I briefly looked it up but came across no such studies either. My speculation is that people in Blue Zones tend to have better immune systems because of their lifestyle (diet + lots of walking, I heard). As a result, they may be able to resist infections better and chronic diseases in general.

In contrast, people in modernized environments are exposed to various stressors (environmental toxins, pollution, work stress, less exercise, more junk food, etc.), which can weaken our immune systems, making us more susceptible to infections and their long-term consequences.