So the world's oldest person is dead. Mrs Edna Parker has died in Indiana, USA at the age of 115. Born on April 20, 1893, Mrs Parker has been recognised by Guinness World Records as the oldest person on earth since the 2007 death in Japan of Yone Minagawa, who was four months her senior. The new oldest living person is Maria de Jesus - great name - of Portugal, who was born on September 10, 1893, eight years before Queen Victoria popped her royal clogs.

Edna Parker had been a widow since 1939. She lived on her own until she was 100, then she moved to a nursing home in which the world's tallest woman - a mere seven feet seven and a quarter inches - lived. Mrs Parker's grandson, Don, said: "We don't know why she's lived so long. But she has never been a worrier and she's always been a thin person, so maybe that has something to do with it."

There seems to be no magic formula. Some centenarians swear by porridge, while others can't abide the stuff. Lots eschew exercise, while a few are still playing for Cowdenbeath. Some - like Mrs Parker - abjure drink and cigarettes, while others say that's what keeps them going. I remember going to see the oldest woman on Iona, Mary Ann Maclean, on her 100th birthday. She opened the door with a fag in her mouth and a glass of sherry in her hand. "Well," she said, ushering me in, "I suppose it'll no be long till ah'm deid, noo." She went on to live for another five years.

What we do know for sure is that centenarians are the fastest-growing segment of the population. This column's research team, headed by the indefatigable Stan Google, has established that in the UK there's been a 90-fold increase since 1911. According to the government's actuary department, the UK's population of centenarians is forecast to soar from about 10,000 now to as many as 1.2 million by 2074. (If you're still alive then, remember that you read it in The Herald first.) In Japan, the number of centenarians quadrupled in the last 10 years - the fastest rate of increase in the world - but this column's informed tip is that China will be ahead in the zimmer race by 2050.

But there's more. The independent think-tank Demos recently suggested average life expectancy could rise to 150 in 30 years' time. The report also quotes the wondrously-named, wondrously titled, Aubrey de Grey, director of Strategies for Engineered Negligible Senescence, as saying that as medicine becomes more powerful, "we will inevitably be able to address ageing just as effectively as we address many diseases today. I think the first person to live to 1000 might be 60 already." This miracle will be achieved, apparently, by genetic engineering, pills and technology. Please, God, no.

Maybe we're just going back to biblical times, when some of the key punters in the sacred narrative went on and on. Methuselah, said to have fathered his first child when he was 187 years old, was reckoned to have lived until he was 969. Goliath, in his day the tallest man in the world - he could have been a candidate for that extraordinary rest home in Indiana - might have gone on for millennia had he not been felled by a coin while he refereed an Old Firm game, or something like that.

Today, the quest for eternal physical life is big business.

Aubrey de Grey has already raised $10m in funding for his organization, the Methuselah Foundation. But who really wants to live for hundreds of years, even with high-tech aids? We are creatures of frail flesh. Having a nuclear-fuelled zimmer is only valuable if you know in which direction the toilet lies, and remember to take your drawers down when you get there.

Mind you, even at a time when permanent youthfulness is the holy grail, experience still has its place. In a Washington in thrall to the youthful President-elect Barack Obama, one Senator Robert Byrd, aged 91, has announced that he will give up the chairmanship of the Senate appropriations committee to Senator Daniel Inouye, who is a mere 84. Senator Inouye said he hoped he was "sufficiently prepared to succeed my mentor." Sufficiently prepared, at the age of 84? I love it.

Here's a better idea. Instead of all this nonsense, we should devote the resources that would have gone into extending the western lifespan to providing clean water for the millions of people in our world whose life expectancy is only 30 years.

All the rest is fluff: or, as the cynical old preacher who wrote the book of Ecclesiastes put it with elegant economy of language: vanity of vanities, all is vanity.