If all goes well, next month my wife’s grandma will turn 100. That is a birthday only around one in 5,000 of her peers will be around to celebrate. Not bad for a woman who, like millions of others, emigrated between the two world wars from eastern Europe to New York, arriving at Ellis Island with all her worldly possessions in a battered suitcase.

So here is a trick question: what do the following four places have in common? Barbagia in Sardinia, Okinawa in Japan, Loma Linda in California, and Nicoya in Costa Rica. Answer: it turns out that they are each pockets of extraordinarily long-living people who make it to 100.

They are what demographers call “blue zones”. People there are up to three times more likely to get their equivalent of a telegram from the Queen.

Finding out what sets these communities apart is the subject a recent book called The Blue Zones by journalist-cum-public health campaigner Dan Buettner. In it he attempts to distil “lessons for living longer from the people who’ve lived the longest”.

At the foundation of the book is a claim, based on a study of Danish twins, that only 25 per cent of life expectancy is “dictated by genes” and the other 75 per cent by our “lifestyles and everyday choices”.

“The Barbagia people have a reputation for kidnapping, stealing and settling scores with long knives”

Of course that is rather simplistic and the proportions may be wrong but behaviour clearly has some impact, and Buettner sets out to find out how.

In doing so, his methodology is unashamedly populist, based on wandering round the globe talking to “blue zone” centenarians and their families, adding a smattering of more rigorous epidemiological and gerontological expertise, and then distilling various self-help recommendations.

We learn that the Barbagia people of Sardinia don’t eat a “Mediterranean” diet but have a “reputation for kidnapping, stealing, and settling scores at the end of very long knives”.

We meet 102-year-old Guiseppe, who is mostly a vegetarian, drinks a litre of red wine a day, and whose mother murdered his father on the steps of a church. Like most Sardinian men he is apparently “sardonic”: likeable, grumpy and stress free.

Maximally sceptical

As for the elders of Okinawa, they ate “lots of vegetables and possessed a strong connection to their ancestors”.

One of them advised: “Work hard, drink mugwort sake before bed, and get a good night’s sleep.”

However, in the face of such anecdotalism even Buettner concedes: “Centenarians can no more tell us how they reached age 100 than a seven foot man can tell us how he got to be so tall.”

That is true, not least because their peers who died well before reaching 100 followed many or all of the same lifestyle nostrums.

And it is at this point - where you may be feeling maximally sceptical - that he changes tack somewhat, seeking to synthesise nine lessons that purport to be “a cross-cultural distillation of the world’s best practices in longevity”.

Here they are: “Design in” physical activity to your everyday routines. Stop eating when you are 80 per cent full (therefore reduce portion sizes, plates and refills, and eat slowly). Avoid too much meat and processed food - instead go for nuts, beans, fruit and vegetables. Drink red wine. Give yourself purpose in life - have a reason for getting out of bed each morning. Take time to chill; stress is bad. Join a spiritual community. Make family a priority. And surround yourself with friends who share these values.

How do you score on these nine items? At www.bluezones.com you can sign up to access 35 questions that apparently can calculate your life expectancy and what you can do to improve it. It told me that my biological age is nine months older than my chronological age but if I improved my lifestyle choices I could gain another 11.9 years.

Folksy framing

This is perhaps where Buettner’s “methodology” could be a strength. Many of his nine items correspond to current received wisdom, so it is not their originality that makes them interesting. It is the trickier question of how you motivate people.

Stories of people in the blue zones help personalise the “opportunity costs” of our current lifestyles, while emphasising the “art of the possible”. And alongside the dry statistics that have often failed to mobilise the public, could it be that his “narrative based policy” can help people to consider changing risk related behaviour?

That is a proposition my organisation, in partnership with AARP (the world’s largest voluntary organisation for retirees) is about to test with a community-wide experiment in a small US city, working with civic and other local leaders to try to get at least a third of the residents to adopt healthier lifestyles.

A programme has been launched to triple the number of children walking to school, the city council has approved money for more bike lanes and pavements, restaurants have signed up to offer healthier food, and a community garden is being built. The ultimate goal is increasing participants’ lives by an average of two years. And the “blue zones” narrative is what got them engaged.

Despite its rather folksy way of framing the issue, it may turn out a good way of motivating and mobilising an effective public health campaign.