Here are the secrets to longevity from the healthiest places on Earth

In 1999, writer Dan Buettner read a World Health Organization article that revealed that people in Okinawa, Japan, had the longest disability-free life expectancy in the world.

Four years later, he read a Danish twin study that showed that only 20% of our life expectancy is determined by genes.

Buettner’s interest was piqued and he set out to find places similar to Okinawa.

“I came to the conclusion that there must be other heterogeneous populations with extremely long life expectancies,” he tells The Post.

“I thought if I could find the common denominators, they might offer some insight for the rest of us.”

In his latest book, “The Blue Zones Secrets for Living Longer: Lessons From the Healthiest Places on Earth” (Dreamscape Media), Buettner revisits the five places on Earth he identified – or “Blue Zones” -, where locals live significantly longer elsewhere on the planet: Nuoro in Sardinia, Italy, Ikaria in Greece, Costa Rica’s Nicoya Peninsula, Okinawa in Japan and Loma Linda in California.

It’s a 20-year quest that has since expanded the idea to include books on healthy eating and lifestyle as Buettner seeks to share the secrets of the Blue Zones’ “super-agers,” as he calls them.

Now, in conjunction with a new series on Netflix, Buettner reveals his Blue Zones’ “Power 9” behaviors – the key characteristics that help these people live longer

From determination to strong social bonds, from prioritizing family to a predominantly plant-based diet rich in fruits, vegetables and whole grains, it is a design for a long, healthy life.

But as Buettner explains, life in the Blue Zones is also changing, as the arrival of highly processed foods and high levels of fat, sugar and salt – coupled with access to the conveniences of modern technology such as cell phones – alters the fundamental nature of residents’ lifestyles.

In fact, one of the original Blue Zones, Okinawa in Japan, can no longer be classified as such.

“Most longevity phenomena in the blue zones will have disappeared within half a generation,” says Büttner.

“But we know the construction plan and it remains in place.”

However, it is no coincidence that people in the Blue Zones not only live the longest, but are also among the happiest in the world.

It is, says Buettner, proof that increasing age does not necessarily mean a worse quality of life.

“I interviewed hundreds of 99-year-olds and never met anyone who didn’t want to live to be 100,” says Büttner.

“All Blue Zones are in the top 20% of the happiest places in the world and Nicoya is in the top 1%.”

“Remember that the same things that help you reach 100 are also the things that create happiness along the way. “