Why do some people live to be 100?

THAT'S THE WHY:One of my favourite stories about Jeanne Calment (below) is that on her birthday a visitor came to the nursing home where the Frenchwoman had lived since age 110.

Bidding her farewell, the visitor said they hoped to see her the same time next year. The birthday girl reportedly quipped: “I don’t see why not. You don’t look so bad to me.”

Calment’s confidence in her own longevity was well founded – she lived to be 122. For most people though, the more modest milestone of 100 is an aspiration. So why does a person make it past the century mark?

A recent paper in Science claimed to have come up with a model to analyse various gene variants and predict exceptional longevity with “77 per cent accuracy”. That research has since been widely questioned, but it’s possible that further studies could highlight more robust associations between an individual’s genetic bounty and their estimated lifespan.

Yet genes are far from the whole picture – your lifestyle, social and physical environment play important roles in how you age – and, of course, an unfortunate accident can call the whole thing off.

In a recent talk hosted by TED, Dan Buettner summarised research on centenarian hotspots around the world including Okinawa in Japan, highlands of Sardinia and a Californian community of Seventh-Day Adventists, where an extraordinary number of people live well beyond their 90s.

Take-home messages that we can learn from the happy aged? Have a reason to live, stop eating before you are stuffed, build movement into your day and value the elders in the community.

To watch Buettner’s presentation, visit http://blog.ted.com/ 2010/01/how_to_live_to.php