herald

Thursday 19 October 2017

Why women continue to outlive men

THEORY: Scientists uncover secret

THE REASON why women live longer than men -- and why the final act of sex discrimination favours females over males -- may at long last have a scientifically valid explanation.

Scientists are close to understanding why men, on average, die younger than women.

Life expectancy in Britain has risen steadily for both sexes over the past few decades and even though the gender gap has narrowed, women are still significantly more likely to live longer than men.

A newborn baby boy in Britain today can expect to live 77.7 years; a newborn baby girl can expect to live to 81.9 years. That is a difference in life expectancy of more than four years. A British man who has already reached 65 can expect to live a further 17.6 years, and a woman of 65 another 20.2 years.

The gender differences become more apparent with age. There are roughly six women to every four men by the age of 85, and the ratio is more than two to one at the age of 100. The oldest documented person to have ever lived was Jeanne Calment, a French woman who died in 1997 at the age of 122 years and 164 days.

Past explanations for why women live longer than men, such as men having physically demanding jobs or engaging in riskier activities such as smoking and drinking, cannot fully explain the gender gap.



routine

It has been a major scientific puzzle why members of the "fairer sex", who have in the past been able to retire earlier than men, live longer.

Now the answer to one of the biggest conundrums of human biology may come down to the fact that the female body seems to be better at carrying out the "routine maintenance" that keeps cells alive and ageing at bay - despite the widespread belief in cosmetic circles, based on skin changes alone, that men age more slowly than women.

Leading scientist Professor Tom Kirkwood believes there is growing evidence to suggest that men are literally more disposable than women, because the cells of their bodies are not genetically programmed to last as long as they are in females.

The theory builds on the "disposable soma" theory, the leading scientific explanation for why we cannot live forever - and now the reason why women live longer than men.

The disposable soma theory says although genes can "live forever" by being passed, the body or "soma" is disposable as it is designed to live only long enough to act as a vehicle for carrying genes to the next generation.

"If the female animal's body is too much weakened by damage, there is a real threat to her chances of making healthy offspring. The man's reproductive role is less directly dependent on his continued good health," Professor Kirkwood writes.

hnews@herald.ie

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