Over half the children born today in the wealthy nations will live for a hundred years according to research published today in the medical journal "The Lancet".

Data collected from more than 30 developed countries shows that the probability of reaching 80 years of age has doubled since 1950 and that people are suffering less serious disability in their old age than before.  Danish research had shown that as many as 30% to 40% of individuals were independent from the ages of 92 to 100.

The study, published today and led by Professor Kaare Christensen, of the Danish Ageing Research Centre at the University of Southern Denmark, confirms that life expectancy has been increasing since 1840, with a rise of two decades over the course of the 20th century, and there was no sign of this trend slowing down.

In 1950 the probability of reaching an age of between 80 and 90 years was, on average, 15 to 16% for women and 12% for men.   In 2002, these figures had risen to 37% for women and 25% for men.  The study points out that until the 1920s, improvements in infant and childhood survival contributed most to the increase in life expectancies.  Since then the increases have been due to better survival of the elderly, which has been particularly evident since the 1970s.

In Europe, data shows that the proportion of men over 65 in good health has been increasing over the past years in countries like Austria, Belgium, Italy, Finland and Germany, and in Belgium, Italy and Sweden in the case of women.

In Spain, however, this figure has stagnated, both for men and women, whereas in countries like Portugal or Holland The number of people reaching the age of 65 without any serious disability has actually gone down.

Increased longevity will obviously have economic implications for the current care system. The scientists explained that a 'redistribution' of workloads could be a partial solution.  "If 60 year olds, or even those who are 70-something, worked less than they currently do, then the majority of people would be able to work fewer hours per week", they explained.  "There is data to suggest that a lower weekly workload but a longer working life could increase life expectancy and improve people's health", they added.

However, the investigating team admits that even this "redistribution of employment" alone would not be enough to solve all the challenges ahead and the economic implications that come with an ageing world population.